Merge pull request #435 from Vavassor/timeline-improvement

"load more" Placeholder

app/src/main/java/com/keylesspalace/tusky/adapter/NotificationsAdapter.java

@@ -47,6 +47,7 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
     private static final int VIEW_TYPE_FOOTER = 1;
     private static final int VIEW_TYPE_STATUS_NOTIFICATION = 2;
     private static final int VIEW_TYPE_FOLLOW = 3;
+    private static final int VIEW_TYPE_PLACEHOLDER = 4;
 
     private List<NotificationViewData> notifications;
     private StatusActionListener statusListener;
@@ -88,6 +89,11 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
                         .inflate(R.layout.item_follow, parent, false);
                 return new FollowViewHolder(view);
             }
+            case VIEW_TYPE_PLACEHOLDER: {
+                View view = LayoutInflater.from(parent.getContext())
+                        .inflate(R.layout.item_status_placeholder, parent, false);
+                return new PlaceholderViewHolder(view);
+            }
         }
     }
 
@@ -95,11 +101,19 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
     public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
         if (position < notifications.size()) {
             NotificationViewData notification = notifications.get(position);
-            Notification.Type type = notification.getType();
+            if (notification instanceof NotificationViewData.Placeholder) {
+                NotificationViewData.Placeholder placeholder = ((NotificationViewData.Placeholder) notification);
+                PlaceholderViewHolder holder = (PlaceholderViewHolder) viewHolder;
+                holder.setup(!placeholder.isLoading(), statusListener);
+                return;
+            }
+            NotificationViewData.Concrete concreteNotificaton =
+                    (NotificationViewData.Concrete) notification;
+            Notification.Type type = concreteNotificaton.getType();
             switch (type) {
                 case MENTION: {
                     StatusViewHolder holder = (StatusViewHolder) viewHolder;
-                    StatusViewData status = notification.getStatusViewData();
+                    StatusViewData.Concrete status = concreteNotificaton.getStatusViewData();
                     holder.setupWithStatus(status,
                             statusListener, mediaPreviewEnabled);
                     break;
@@ -107,18 +121,18 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
                 case FAVOURITE:
                 case REBLOG: {
                     StatusNotificationViewHolder holder = (StatusNotificationViewHolder) viewHolder;
-                    holder.setMessage(type, notification.getAccount().getDisplayName(),
+                    holder.setMessage(type, concreteNotificaton.getAccount().getDisplayName(),
-                            notification.getStatusViewData());
+                            concreteNotificaton.getStatusViewData());
-                    holder.setupButtons(notificationActionListener, notification.getAccount().id);
+                    holder.setupButtons(notificationActionListener, concreteNotificaton.getAccount().id);
-                    holder.setAvatars(notification.getStatusViewData().getAvatar(),
+                    holder.setAvatars(concreteNotificaton.getStatusViewData().getAvatar(),
-                            notification.getAccount().avatar);
+                            concreteNotificaton.getAccount().avatar);
                     break;
                 }
                 case FOLLOW: {
                     FollowViewHolder holder = (FollowViewHolder) viewHolder;
-                    holder.setMessage(notification.getAccount().getDisplayName(),
+                    holder.setMessage(concreteNotificaton.getAccount().getDisplayName(),
-                            notification.getAccount().username, notification.getAccount().avatar);
+                            concreteNotificaton.getAccount().username, concreteNotificaton.getAccount().avatar);
-                    holder.setupButtons(notificationActionListener, notification.getAccount().id);
+                    holder.setupButtons(notificationActionListener, concreteNotificaton.getAccount().id);
                     break;
                 }
             }
@@ -139,18 +153,25 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
             return VIEW_TYPE_FOOTER;
         } else {
             NotificationViewData notification = notifications.get(position);
-            switch (notification.getType()) {
+            if (notification instanceof NotificationViewData.Concrete) {
-                default:
+                NotificationViewData.Concrete concrete = ((NotificationViewData.Concrete) notification);
-                case MENTION: {
+                switch (concrete.getType()) {
-                    return VIEW_TYPE_MENTION;
+                    default:
-                }
+                    case MENTION: {
-                case FAVOURITE:
+                        return VIEW_TYPE_MENTION;
-                case REBLOG: {
+                    }
-                    return VIEW_TYPE_STATUS_NOTIFICATION;
+                    case FAVOURITE:
-                }
+                    case REBLOG: {
-                case FOLLOW: {
+                        return VIEW_TYPE_STATUS_NOTIFICATION;
-                    return VIEW_TYPE_FOLLOW;
+                    }
+                    case FOLLOW: {
+                        return VIEW_TYPE_FOLLOW;
+                    }
                 }
+            } else if (notification instanceof NotificationViewData.Placeholder) {
+                return VIEW_TYPE_PLACEHOLDER;
+            } else {
+                throw new AssertionError("Unknown notification type");
             }
         }
     }
@@ -258,7 +279,8 @@ public class NotificationsAdapter extends RecyclerView.Adapter {
             notificationAvatar.setColorFilter(darkerFilter, PorterDuff.Mode.MULTIPLY);
         }
 
-        void setMessage(Notification.Type type, String displayName, StatusViewData status) {
+        void setMessage(Notification.Type type, String displayName,
+                        StatusViewData.Concrete status) {
             Context context = message.getContext();
             String format;
             switch (type) {

app/src/main/java/com/keylesspalace/tusky/adapter/PlaceholderViewHolder.java

@@ -0,0 +1,49 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
+package com.keylesspalace.tusky.adapter;
+
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+import android.widget.Button;
+
+import com.keylesspalace.tusky.R;
+import com.keylesspalace.tusky.interfaces.StatusActionListener;
+
+public class PlaceholderViewHolder extends RecyclerView.ViewHolder {
+
+    private Button loadMoreButton;
+
+
+    PlaceholderViewHolder(View itemView) {
+        super(itemView);
+        loadMoreButton = itemView.findViewById(R.id.button_load_more);
+
+    }
+
+    public void setup(boolean enabled, final StatusActionListener listener){
+        loadMoreButton.setEnabled(enabled);
+        if(enabled) {
+            loadMoreButton.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    loadMoreButton.setEnabled(false);
+                    listener.onLoadMore(getAdapterPosition());
+                }
+            });
+        }
+    }
+
+}

app/src/main/java/com/keylesspalace/tusky/adapter/StatusBaseViewHolder.java

@@ -271,6 +271,9 @@ class StatusBaseViewHolder extends RecyclerView.ViewHolder {
             sensitiveMediaShow.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {
+                    if (getAdapterPosition() != RecyclerView.NO_POSITION) {
+                        listener.onContentHiddenChange(false, getAdapterPosition());
+                    }
                     v.setVisibility(View.GONE);
                     sensitiveMediaWarning.setVisibility(View.VISIBLE);
                 }
@@ -470,7 +473,7 @@ class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         container.setOnClickListener(viewThreadListener);
     }
 
-    void setupWithStatus(StatusViewData status, final StatusActionListener listener,
+    void setupWithStatus(StatusViewData.Concrete status, final StatusActionListener listener,
                          boolean mediaPreviewEnabled) {
         setDisplayName(status.getUserFullName());
         setUsername(status.getNickname());

app/src/main/java/com/keylesspalace/tusky/adapter/StatusDetailedViewHolder.java

@@ -85,7 +85,7 @@ class StatusDetailedViewHolder extends StatusBaseViewHolder {
     }
 
     @Override
-    void setupWithStatus(final StatusViewData status, final StatusActionListener listener,
+    void setupWithStatus(final StatusViewData.Concrete status, final StatusActionListener listener,
                          boolean mediaPreviewEnabled) {
         super.setupWithStatus(status, listener, mediaPreviewEnabled);
         reblogs.setText(status.getReblogsCount());

app/src/main/java/com/keylesspalace/tusky/adapter/StatusViewHolder.java

@@ -67,7 +67,7 @@ public class StatusViewHolder extends StatusBaseViewHolder {
     }
 
     @Override
-    void setupWithStatus(StatusViewData status, final StatusActionListener listener,
+    void setupWithStatus(StatusViewData.Concrete status, final StatusActionListener listener,
                          boolean mediaPreviewEnabled) {
         super.setupWithStatus(status, listener, mediaPreviewEnabled);
 

app/src/main/java/com/keylesspalace/tusky/adapter/ThreadAdapter.java

@@ -33,7 +33,7 @@ public class ThreadAdapter extends RecyclerView.Adapter {
     private static final int VIEW_TYPE_STATUS = 0;
     private static final int VIEW_TYPE_STATUS_DETAILED = 1;
 
-    private List<StatusViewData> statuses;
+    private List<StatusViewData.Concrete> statuses;
     private StatusActionListener statusActionListener;
     private boolean mediaPreviewEnabled;
     private int detailedStatusPosition;
@@ -66,13 +66,12 @@ public class ThreadAdapter extends RecyclerView.Adapter {
 
     @Override
     public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
+        StatusViewData.Concrete status = statuses.get(position);
         if (position == detailedStatusPosition) {
             StatusDetailedViewHolder holder = (StatusDetailedViewHolder) viewHolder;
-            StatusViewData status = statuses.get(position);
             holder.setupWithStatus(status, statusActionListener, mediaPreviewEnabled);
         } else {
             StatusViewHolder holder = (StatusViewHolder) viewHolder;
-            StatusViewData status = statuses.get(position);
             holder.setupWithStatus(status, statusActionListener, mediaPreviewEnabled);
         }
     }
@@ -91,13 +90,13 @@ public class ThreadAdapter extends RecyclerView.Adapter {
         return statuses.size();
     }
 
-    public void setStatuses(List<StatusViewData> statuses) {
+    public void setStatuses(List<StatusViewData.Concrete> statuses) {
         this.statuses.clear();
         this.statuses.addAll(statuses);
         notifyDataSetChanged();
     }
 
-    public void addItem(int position, StatusViewData statusViewData) {
+    public void addItem(int position, StatusViewData.Concrete statusViewData) {
         statuses.add(position, statusViewData);
         notifyItemInserted(position);
     }
@@ -109,12 +108,12 @@ public class ThreadAdapter extends RecyclerView.Adapter {
         notifyItemRangeRemoved(0, oldSize);
     }
 
-    public void addAll(int position, List<StatusViewData> statuses) {
+    public void addAll(int position, List<StatusViewData.Concrete> statuses) {
         this.statuses.addAll(position, statuses);
         notifyItemRangeInserted(position, statuses.size());
     }
 
-    public void addAll(List<StatusViewData> statuses) {
+    public void addAll(List<StatusViewData.Concrete> statuses) {
         int end = statuses.size();
         this.statuses.addAll(statuses);
         notifyItemRangeInserted(end, statuses.size());
@@ -126,7 +125,7 @@ public class ThreadAdapter extends RecyclerView.Adapter {
         notifyDataSetChanged();
     }
 
-    public void setItem(int position, StatusViewData status, boolean notifyAdapter) {
+    public void setItem(int position, StatusViewData.Concrete status, boolean notifyAdapter) {
         statuses.set(position, status);
         if (notifyAdapter) {
             notifyItemChanged(position);
@@ -134,7 +133,7 @@ public class ThreadAdapter extends RecyclerView.Adapter {
     }
 
     @Nullable
-    public StatusViewData getItem(int position) {
+    public StatusViewData.Concrete getItem(int position) {
         if (position != RecyclerView.NO_POSITION && position >= 0 && position < statuses.size()) {
             return statuses.get(position);
         } else {

app/src/main/java/com/keylesspalace/tusky/adapter/TimelineAdapter.java

@@ -31,6 +31,7 @@ import java.util.List;
 public class TimelineAdapter extends RecyclerView.Adapter {
     private static final int VIEW_TYPE_STATUS = 0;
     private static final int VIEW_TYPE_FOOTER = 1;
+    private static final int VIEW_TYPE_PLACEHOLDER = 2;
 
     private List<StatusViewData> statuses;
     private StatusActionListener statusListener;
@@ -59,15 +60,28 @@ public class TimelineAdapter extends RecyclerView.Adapter {
                         .inflate(R.layout.item_footer, viewGroup, false);
                 return new FooterViewHolder(view);
             }
+            case VIEW_TYPE_PLACEHOLDER: {
+                View view = LayoutInflater.from(viewGroup.getContext())
+                        .inflate(R.layout.item_status_placeholder, viewGroup, false);
+                return new PlaceholderViewHolder(view);
+            }
         }
     }
 
     @Override
     public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
         if (position < statuses.size()) {
-            StatusViewHolder holder = (StatusViewHolder) viewHolder;
             StatusViewData status = statuses.get(position);
-            holder.setupWithStatus(status, statusListener, mediaPreviewEnabled);
+            if (status instanceof StatusViewData.Placeholder) {
+                PlaceholderViewHolder holder = (PlaceholderViewHolder) viewHolder;
+                holder.setup(!((StatusViewData.Placeholder) status).isLoading(), statusListener);
+            } else {
+
+                StatusViewHolder holder = (StatusViewHolder) viewHolder;
+                holder.setupWithStatus((StatusViewData.Concrete) status,
+                        statusListener, mediaPreviewEnabled);
+            }
+
         } else {
             FooterViewHolder holder = (FooterViewHolder) viewHolder;
             holder.setState(footerState);
@@ -84,7 +98,11 @@ public class TimelineAdapter extends RecyclerView.Adapter {
         if (position == statuses.size()) {
             return VIEW_TYPE_FOOTER;
         } else {
-            return VIEW_TYPE_STATUS;
+            if (statuses.get(position) instanceof StatusViewData.Placeholder) {
+                return VIEW_TYPE_PLACEHOLDER;
+            } else {
+                return VIEW_TYPE_STATUS;
+            }
         }
     }
 

app/src/main/java/com/keylesspalace/tusky/entity/Status.java

@@ -106,19 +106,17 @@ public class Status {
     public static final int MAX_MEDIA_ATTACHMENTS = 4;
 
     @Override
-    public int hashCode() {
+    public boolean equals(Object o) {
-        return id.hashCode();
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Status status = (Status) o;
+        return id != null ? id.equals(status.id) : status.id == null;
     }
 
     @Override
-    public boolean equals(Object other) {
+    public int hashCode() {
-        if (this.id == null) {
+        return id != null ? id.hashCode() : 0;
-            return this == other;
-        } else if (!(other instanceof Status)) {
-            return false;
-        }
-        Status status = (Status) other;
-        return status.id.equals(this.id);
     }
 
     public static class MediaAttachment {

app/src/main/java/com/keylesspalace/tusky/fragment/NotificationsFragment.java

@@ -44,6 +44,8 @@ import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.interfaces.ActionButtonActivity;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.receiver.TimelineReceiver;
+import com.keylesspalace.tusky.util.CollectionUtil;
+import com.keylesspalace.tusky.util.Either;
 import com.keylesspalace.tusky.util.HttpHeaderLink;
 import com.keylesspalace.tusky.util.ListUtils;
 import com.keylesspalace.tusky.util.PairedList;
@@ -54,7 +56,6 @@ import com.keylesspalace.tusky.viewdata.NotificationViewData;
 import com.keylesspalace.tusky.viewdata.StatusViewData;
 
 import java.util.Iterator;
-import java.util.LinkedHashSet;
 import java.util.List;
 
 import retrofit2.Call;
@@ -65,11 +66,29 @@ public class NotificationsFragment extends SFragment implements
         SwipeRefreshLayout.OnRefreshListener, StatusActionListener,
         NotificationsAdapter.NotificationActionListener,
         SharedPreferences.OnSharedPreferenceChangeListener {
-    private static final String TAG = "Notifications"; // logging tag
+    private static final String TAG = "NotificationF"; // logging tag
+
+    private static final int LOAD_AT_ONCE = 30;
 
     private enum FetchEnd {
         TOP,
-        BOTTOM
+        BOTTOM,
+        MIDDLE
+    }
+
+    /**
+     * Placeholder for the notifications. Consider moving to the separate class to hide constructor
+     * and reuse in different places as needed.
+     */
+    private static final class Placeholder {
+        private static final Placeholder INSTANCE = new Placeholder();
+
+        public static Placeholder getInstance() {
+            return INSTANCE;
+        }
+
+        private Placeholder() {
+        }
     }
 
     private SwipeRefreshLayout swipeRefreshLayout;
@@ -87,11 +106,17 @@ public class NotificationsFragment extends SFragment implements
     private String bottomId;
     private String topId;
 
-    private final PairedList<Notification, NotificationViewData> notifications
+    // Each element is either a Notification for loading data or a Placeholder
-            = new PairedList<>(new Function<Notification, NotificationViewData>() {
+    private final PairedList<Either<Placeholder, Notification>, NotificationViewData> notifications
+            = new PairedList<>(new Function<Either<Placeholder, Notification>, NotificationViewData>() {
         @Override
-        public NotificationViewData apply(Notification input) {
+        public NotificationViewData apply(Either<Placeholder, Notification> input) {
-            return ViewDataUtils.notificationToViewData(input);
+            if (input.isRight()) {
+                Notification notification = input.getAsRight();
+                return ViewDataUtils.notificationToViewData(notification);
+            } else {
+                return new NotificationViewData.Placeholder(false);
+            }
         }
     });
 
@@ -156,12 +181,10 @@ public class NotificationsFragment extends SFragment implements
         TabLayout layout = activity.findViewById(R.id.tab_layout);
         onTabSelectedListener = new TabLayout.OnTabSelectedListener() {
             @Override
-            public void onTabSelected(TabLayout.Tab tab) {
+            public void onTabSelected(TabLayout.Tab tab) {}
-            }
 
             @Override
-            public void onTabUnselected(TabLayout.Tab tab) {
+            public void onTabUnselected(TabLayout.Tab tab) {}
-            }
 
             @Override
             public void onTabReselected(TabLayout.Tab tab) {
@@ -185,7 +208,7 @@ public class NotificationsFragment extends SFragment implements
                 ActionButtonActivity activity = (ActionButtonActivity) getActivity();
                 FloatingActionButton composeButton = activity.getActionButton();
 
-                if(composeButton != null) {
+                if (composeButton != null) {
                     if (hideFab) {
                         if (dy > 0 && composeButton.isShown()) {
                             composeButton.hide(); // hides the button if we're scrolling down
@@ -220,18 +243,17 @@ public class NotificationsFragment extends SFragment implements
 
     @Override
     public void onRefresh() {
-        sendFetchNotificationsRequest(null, topId, FetchEnd.TOP);
+        sendFetchNotificationsRequest(null, topId, FetchEnd.TOP, -1);
     }
 
     @Override
     public void onReply(int position) {
-        Notification notification = notifications.get(position);
+        super.reply(notifications.get(position).getAsRight().status);
-        super.reply(notification.status);
     }
 
     @Override
     public void onReblog(final boolean reblog, final int position) {
-        final Notification notification = notifications.get(position);
+        final Notification notification = notifications.get(position).getAsRight();
         final Status status = notification.status;
         reblogWithCallback(status, reblog, new Callback<Status>() {
             @Override
@@ -242,7 +264,9 @@ public class NotificationsFragment extends SFragment implements
                     if (status.reblog != null) {
                         status.reblog.reblogged = reblog;
                     }
-                    notifications.set(position, notification);
+                    // Java's type inference *eyeroll*
+                    notifications.set(position,
+                            Either.<Placeholder, Notification>right(notification));
 
                     adapter.updateItemWithNotify(position, notifications.getPairedItem(position), true);
 
@@ -252,8 +276,7 @@ public class NotificationsFragment extends SFragment implements
 
             @Override
             public void onFailure(@NonNull Call<Status> call, @NonNull Throwable t) {
-                Log.d(getClass().getSimpleName(), "Failed to reblog status: " + status.id);
+                Log.d(getClass().getSimpleName(), "Failed to reblog status: " + status.id, t);
-                t.printStackTrace();
             }
         });
     }
@@ -261,7 +284,7 @@ public class NotificationsFragment extends SFragment implements
 
     @Override
     public void onFavourite(final boolean favourite, final int position) {
-        final Notification notification = notifications.get(position);
+        final Notification notification = notifications.get(position).getAsRight();
         final Status status = notification.status;
         favouriteWithCallback(status, favourite, new Callback<Status>() {
             @Override
@@ -273,7 +296,8 @@ public class NotificationsFragment extends SFragment implements
                         status.reblog.favourited = favourite;
                     }
 
-                    notifications.set(position, notification);
+                    notifications.set(position,
+                            Either.<Placeholder, Notification>right(notification));
 
                     adapter.updateItemWithNotify(position, notifications.getPairedItem(position), true);
 
@@ -283,15 +307,14 @@ public class NotificationsFragment extends SFragment implements
 
             @Override
             public void onFailure(@NonNull Call<Status> call, @NonNull Throwable t) {
-                Log.d(getClass().getSimpleName(), "Failed to favourite status: " + status.id);
+                Log.d(getClass().getSimpleName(), "Failed to favourite status: " + status.id, t);
-                t.printStackTrace();
             }
         });
     }
 
     @Override
     public void onMore(View view, int position) {
-        Notification notification = notifications.get(position);
+        Notification notification = notifications.get(position).getAsRight();
         super.more(notification.status, view, position);
     }
 
@@ -303,24 +326,25 @@ public class NotificationsFragment extends SFragment implements
 
     @Override
     public void onViewThread(int position) {
-        Notification notification = notifications.get(position);
+        Notification notification = notifications.get(position).getAsRight();
         super.viewThread(notification.status);
     }
 
     @Override
     public void onOpenReblog(int position) {
-        Notification notification = notifications.get(position);
+        Notification notification = notifications.get(position).getAsRight();
-        if (notification != null) onViewAccount(notification.account.id);
+        onViewAccount(notification.account.id);
     }
 
     @Override
     public void onExpandedChange(boolean expanded, int position) {
-        NotificationViewData old = notifications.getPairedItem(position);
+        NotificationViewData.Concrete old =
-        StatusViewData statusViewData =
+                (NotificationViewData.Concrete) notifications.getPairedItem(position);
+        StatusViewData.Concrete statusViewData =
                 new StatusViewData.Builder(old.getStatusViewData())
                         .setIsExpanded(expanded)
                         .createStatusViewData();
-        NotificationViewData notificationViewData = new NotificationViewData(old.getType(),
+        NotificationViewData notificationViewData = new NotificationViewData.Concrete(old.getType(),
                 old.getId(), old.getAccount(), statusViewData);
         notifications.setPairedItem(position, notificationViewData);
         adapter.updateItemWithNotify(position, notificationViewData, false);
@@ -328,17 +352,38 @@ public class NotificationsFragment extends SFragment implements
 
     @Override
     public void onContentHiddenChange(boolean isShowing, int position) {
-        NotificationViewData old = notifications.getPairedItem(position);
+        NotificationViewData.Concrete old =
-        StatusViewData statusViewData =
+                (NotificationViewData.Concrete) notifications.getPairedItem(position);
+        StatusViewData.Concrete statusViewData =
                 new StatusViewData.Builder(old.getStatusViewData())
                         .setIsShowingSensitiveContent(isShowing)
                         .createStatusViewData();
-        NotificationViewData notificationViewData = new NotificationViewData(old.getType(),
+        NotificationViewData notificationViewData = new NotificationViewData.Concrete(old.getType(),
                 old.getId(), old.getAccount(), statusViewData);
         notifications.setPairedItem(position, notificationViewData);
         adapter.updateItemWithNotify(position, notificationViewData, false);
     }
 
+    @Override
+    public void onLoadMore(int position) {
+        //check bounds before accessing list,
+        if (notifications.size() >= position && position > 0) {
+            Notification previous = notifications.get(position - 1).getAsRightOrNull();
+            Notification next = notifications.get(position + 1).getAsRightOrNull();
+            if (previous == null || next == null) {
+                Log.e(TAG, "Failed to load more, invalid placeholder position: " + position);
+                return;
+            }
+            sendFetchNotificationsRequest(previous.id, next.id, FetchEnd.MIDDLE, position);
+            NotificationViewData notificationViewData =
+                    new NotificationViewData.Placeholder(true);
+            notifications.setPairedItem(position, notificationViewData);
+            adapter.updateItemWithNotify(position, notificationViewData, false);
+        } else {
+            Log.d(TAG, "error loading more");
+        }
+    }
+
     @Override
     public void onViewTag(String tag) {
         super.viewTag(tag);
@@ -374,10 +419,11 @@ public class NotificationsFragment extends SFragment implements
     @Override
     public void removeAllByAccountId(String accountId) {
         // using iterator to safely remove items while iterating
-        Iterator<Notification> iterator = notifications.iterator();
+        Iterator<Either<Placeholder, Notification>> iterator = notifications.iterator();
         while (iterator.hasNext()) {
-            Notification notification = iterator.next();
+            Either<Placeholder, Notification> notification = iterator.next();
-            if (notification.account.id.equals(accountId)) {
+            Notification maybeNotification = notification.getAsRightOrNull();
+            if (maybeNotification != null && maybeNotification.account.id.equals(accountId)) {
                 iterator.remove();
             }
         }
@@ -385,7 +431,7 @@ public class NotificationsFragment extends SFragment implements
     }
 
     private void onLoadMore() {
-        sendFetchNotificationsRequest(bottomId, null, FetchEnd.BOTTOM);
+        sendFetchNotificationsRequest(bottomId, null, FetchEnd.BOTTOM, -1);
     }
 
     private void jumpToTop() {
@@ -394,7 +440,7 @@ public class NotificationsFragment extends SFragment implements
     }
 
     private void sendFetchNotificationsRequest(String fromId, String uptoId,
-                                               final FetchEnd fetchEnd) {
+                                               final FetchEnd fetchEnd, final int pos) {
         /* If there is a fetch already ongoing, record however many fetches are requested and
          * fulfill them after it's complete. */
         if (fetchEnd == FetchEnd.TOP && topLoading) {
@@ -418,7 +464,7 @@ public class NotificationsFragment extends SFragment implements
             });
         }
 
-        Call<List<Notification>> call = mastodonApi.notifications(fromId, uptoId, null);
+        Call<List<Notification>> call = mastodonApi.notifications(fromId, uptoId, LOAD_AT_ONCE);
 
         call.enqueue(new Callback<List<Notification>>() {
             @Override
@@ -426,22 +472,22 @@ public class NotificationsFragment extends SFragment implements
                                    @NonNull Response<List<Notification>> response) {
                 if (response.isSuccessful()) {
                     String linkHeader = response.headers().get("Link");
-                    onFetchNotificationsSuccess(response.body(), linkHeader, fetchEnd);
+                    onFetchNotificationsSuccess(response.body(), linkHeader, fetchEnd, pos);
                 } else {
-                    onFetchNotificationsFailure(new Exception(response.message()), fetchEnd);
+                    onFetchNotificationsFailure(new Exception(response.message()), fetchEnd, pos);
                 }
             }
 
             @Override
             public void onFailure(@NonNull Call<List<Notification>> call, @NonNull Throwable t) {
-                onFetchNotificationsFailure((Exception) t, fetchEnd);
+                onFetchNotificationsFailure((Exception) t, fetchEnd, pos);
             }
         });
         callList.add(call);
     }
 
     private void onFetchNotificationsSuccess(List<Notification> notifications, String linkHeader,
-                                             FetchEnd fetchEnd) {
+                                             FetchEnd fetchEnd, int pos) {
         List<HttpHeaderLink> links = HttpHeaderLink.parse(linkHeader);
         switch (fetchEnd) {
             case TOP: {
@@ -453,6 +499,10 @@ public class NotificationsFragment extends SFragment implements
                 update(notifications, null, uptoId);
                 break;
             }
+            case MIDDLE: {
+                replacePlaceholderWithNotifications(notifications, pos);
+                break;
+            }
             case BOTTOM: {
                 HttpHeaderLink next = HttpHeaderLink.findByRelationType(links, "next");
                 String fromId = null;
@@ -489,8 +539,20 @@ public class NotificationsFragment extends SFragment implements
         swipeRefreshLayout.setRefreshing(false);
     }
 
-    public void update(@Nullable List<Notification> newNotifications, @Nullable String fromId,
+    private void onFetchNotificationsFailure(Exception exception, FetchEnd fetchEnd, int position) {
-                       @Nullable String uptoId) {
+        swipeRefreshLayout.setRefreshing(false);
+        if (fetchEnd == FetchEnd.MIDDLE && !notifications.get(position).isRight()) {
+            NotificationViewData placeholderVD =
+                    new NotificationViewData.Placeholder(false);
+            notifications.setPairedItem(position, placeholderVD);
+            adapter.updateItemWithNotify(position, placeholderVD, true);
+        }
+        Log.e(TAG, "Fetch failure: " + exception.getMessage());
+        fulfillAnyQueuedFetches(fetchEnd);
+    }
+
+    private void update(@Nullable List<Notification> newNotifications, @Nullable String fromId,
+                        @Nullable String uptoId) {
         if (ListUtils.isEmpty(newNotifications)) {
             return;
         }
@@ -500,26 +562,31 @@ public class NotificationsFragment extends SFragment implements
         if (uptoId != null) {
             topId = uptoId;
         }
+        List<Either<Placeholder, Notification>> liftedNew =
+                liftNotificationList(newNotifications);
         if (notifications.isEmpty()) {
-            // This construction removes duplicates while preserving order.
+            notifications.addAll(liftedNew);
-            notifications.addAll(new LinkedHashSet<>(newNotifications));
         } else {
-            int index = notifications.indexOf(newNotifications.get(newNotifications.size() - 1));
+            int index = notifications.indexOf(liftedNew.get(newNotifications.size() - 1));
             for (int i = 0; i < index; i++) {
                 notifications.remove(0);
             }
-            int newIndex = newNotifications.indexOf(notifications.get(0));
+
+
+            int newIndex = liftedNew.indexOf(notifications.get(0));
             if (newIndex == -1) {
-                notifications.addAll(0, newNotifications);
+                if (index == -1 && liftedNew.size() >= LOAD_AT_ONCE) {
+                    liftedNew.add(Either.<Placeholder, Notification>left(Placeholder.getInstance()));
+                }
+                notifications.addAll(0, liftedNew);
             } else {
-                List<Notification> sublist = newNotifications.subList(0, newIndex);
+                notifications.addAll(0, liftedNew.subList(0, newIndex));
-                notifications.addAll(0, sublist);
             }
         }
         adapter.update(notifications.getPairedCopy());
     }
 
-    public void addItems(List<Notification> newNotifications, @Nullable String fromId) {
+    private void addItems(List<Notification> newNotifications, @Nullable String fromId) {
         if (ListUtils.isEmpty(newNotifications)) {
             return;
         }
@@ -527,9 +594,10 @@ public class NotificationsFragment extends SFragment implements
             bottomId = fromId;
         }
         int end = notifications.size();
-        Notification last = notifications.get(end - 1);
+        List<Either<Placeholder, Notification>> liftedNew = liftNotificationList(newNotifications);
-        if (last != null && !findNotification(newNotifications, last.id)) {
+        Either<Placeholder, Notification> last = notifications.get(end - 1);
-            notifications.addAll(newNotifications);
+        if (last != null && liftedNew.indexOf(last) == -1) {
+            notifications.addAll(liftedNew);
             List<NotificationViewData> newViewDatas = notifications.getPairedCopy()
                     .subList(notifications.size() - newNotifications.size(),
                             notifications.size());
@@ -537,21 +605,6 @@ public class NotificationsFragment extends SFragment implements
         }
     }
 
-    private static boolean findNotification(List<Notification> notifications, String id) {
-        for (Notification notification : notifications) {
-            if (notification.id.equals(id)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private void onFetchNotificationsFailure(Exception exception, FetchEnd fetchEnd) {
-        swipeRefreshLayout.setRefreshing(false);
-        Log.e(TAG, "Fetch failure: " + exception.getMessage());
-        fulfillAnyQueuedFetches(fetchEnd);
-    }
-
     private void fulfillAnyQueuedFetches(FetchEnd fetchEnd) {
         switch (fetchEnd) {
             case BOTTOM: {
@@ -573,9 +626,43 @@ public class NotificationsFragment extends SFragment implements
         }
     }
 
+    private void replacePlaceholderWithNotifications(List<Notification> newNotifications, int pos) {
+        // Remove placeholder
+        notifications.remove(pos);
+
+        if (ListUtils.isEmpty(newNotifications)) {
+            adapter.update(notifications.getPairedCopy());
+            return;
+        }
+
+        List<Either<Placeholder, Notification>> liftedNew = liftNotificationList(newNotifications);
+
+        // If we fetched less posts than in the limit, it means that the hole is not filled
+        // If we fetched at least as much it means that there are more posts to load and we should
+        // insert new placeholder
+        if (newNotifications.size() >= LOAD_AT_ONCE) {
+            liftedNew.add(Either.<Placeholder, Notification>left(Placeholder.getInstance()));
+        }
+
+        notifications.addAll(pos, liftedNew);
+        adapter.update(notifications.getPairedCopy());
+    }
+
+    private final Function<Notification, Either<Placeholder, Notification>> notificationLifter =
+            new Function<Notification, Either<Placeholder, Notification>>() {
+                @Override
+                public Either<Placeholder, Notification> apply(Notification input) {
+                    return Either.right(input);
+                }
+            };
+
+    private List<Either<Placeholder, Notification>> liftNotificationList(List<Notification> list) {
+        return CollectionUtil.map(list, notificationLifter);
+    }
+
     private void fullyRefresh() {
         adapter.clear();
         notifications.clear();
-        sendFetchNotificationsRequest(null, null, FetchEnd.TOP);
+        sendFetchNotificationsRequest(null, null, FetchEnd.TOP, -1);
     }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/SFragment.java

@@ -21,6 +21,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.ActivityOptionsCompat;
 import android.support.v4.content.LocalBroadcastManager;
@@ -148,10 +149,10 @@ public abstract class SFragment extends BaseFragment implements AdapterItemRemov
         Call<Relationship> call = mastodonApi.muteAccount(id);
         call.enqueue(new Callback<Relationship>() {
             @Override
-            public void onResponse(Call<Relationship> call, Response<Relationship> response) {}
+            public void onResponse(@NonNull Call<Relationship> call, @NonNull Response<Relationship> response) {}
 
             @Override
-            public void onFailure(Call<Relationship> call, Throwable t) {}
+            public void onFailure(@NonNull Call<Relationship> call, @NonNull Throwable t) {}
         });
         callList.add(call);
         Intent intent = new Intent(TimelineReceiver.Types.MUTE_ACCOUNT);
@@ -164,10 +165,10 @@ public abstract class SFragment extends BaseFragment implements AdapterItemRemov
         Call<Relationship> call = mastodonApi.blockAccount(id);
         call.enqueue(new Callback<Relationship>() {
             @Override
-            public void onResponse(Call<Relationship> call, retrofit2.Response<Relationship> response) {}
+            public void onResponse(@NonNull Call<Relationship> call, @NonNull retrofit2.Response<Relationship> response) {}
 
             @Override
-            public void onFailure(Call<Relationship> call, Throwable t) {}
+            public void onFailure(@NonNull Call<Relationship> call, @NonNull Throwable t) {}
         });
         callList.add(call);
         Intent intent = new Intent(TimelineReceiver.Types.BLOCK_ACCOUNT);
@@ -180,10 +181,10 @@ public abstract class SFragment extends BaseFragment implements AdapterItemRemov
         Call<ResponseBody> call = mastodonApi.deleteStatus(id);
         call.enqueue(new Callback<ResponseBody>() {
             @Override
-            public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> response) {}
+            public void onResponse(@NonNull Call<ResponseBody> call, @NonNull retrofit2.Response<ResponseBody> response) {}
 
             @Override
-            public void onFailure(Call<ResponseBody> call, Throwable t) {}
+            public void onFailure(@NonNull Call<ResponseBody> call, @NonNull Throwable t) {}
         });
         callList.add(call);
     }

app/src/main/java/com/keylesspalace/tusky/fragment/TimelineFragment.java

@@ -15,6 +15,7 @@
 
 package com.keylesspalace.tusky.fragment;
 
+import android.arch.core.util.Function;
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.graphics.drawable.Drawable;
@@ -25,6 +26,7 @@ import android.support.annotation.Nullable;
 import android.support.design.widget.FloatingActionButton;
 import android.support.design.widget.TabLayout;
 import android.support.v4.content.LocalBroadcastManager;
+import android.support.v4.util.Pair;
 import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.widget.DividerItemDecoration;
 import android.support.v7.widget.LinearLayoutManager;
@@ -43,6 +45,8 @@ import com.keylesspalace.tusky.interfaces.ActionButtonActivity;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.network.MastodonApi;
 import com.keylesspalace.tusky.receiver.TimelineReceiver;
+import com.keylesspalace.tusky.util.CollectionUtil;
+import com.keylesspalace.tusky.util.Either;
 import com.keylesspalace.tusky.util.HttpHeaderLink;
 import com.keylesspalace.tusky.util.ListUtils;
 import com.keylesspalace.tusky.util.PairedList;
@@ -52,7 +56,6 @@ import com.keylesspalace.tusky.view.EndlessOnScrollListener;
 import com.keylesspalace.tusky.viewdata.StatusViewData;
 
 import java.util.Iterator;
-import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Locale;
 
@@ -64,10 +67,12 @@ public class TimelineFragment extends SFragment implements
         SwipeRefreshLayout.OnRefreshListener,
         StatusActionListener,
         SharedPreferences.OnSharedPreferenceChangeListener {
-    private static final String TAG = "Timeline"; // logging tag
+    private static final String TAG = "TimelineF"; // logging tag
     private static final String KIND_ARG = "kind";
     private static final String HASHTAG_OR_ID_ARG = "hashtag_or_id";
 
+    private static final int LOAD_AT_ONCE = 30;
+
     public enum Kind {
         HOME,
         PUBLIC_LOCAL,
@@ -80,6 +85,7 @@ public class TimelineFragment extends SFragment implements
     private enum FetchEnd {
         TOP,
         BOTTOM,
+        MIDDLE
     }
 
     private SwipeRefreshLayout swipeRefreshLayout;
@@ -102,8 +108,18 @@ public class TimelineFragment extends SFragment implements
     private String bottomId;
     @Nullable
     private String topId;
-    private PairedList<Status, StatusViewData> statuses =
+    private PairedList<Either<Placeholder, Status>, StatusViewData> statuses =
-            new PairedList<>(ViewDataUtils.statusMapper());
+            new PairedList<>(new Function<Either<Placeholder, Status>, StatusViewData>() {
+                @Override
+                public StatusViewData apply(Either<Placeholder, Status> input) {
+                    Status status = input.getAsRightOrNull();
+                    if (status != null) {
+                        return ViewDataUtils.statusToViewData(status);
+                    } else {
+                        return new StatusViewData.Placeholder(false);
+                    }
+                }
+            });
 
     public static TimelineFragment newInstance(Kind kind) {
         TimelineFragment fragment = new TimelineFragment();
@@ -122,6 +138,17 @@ public class TimelineFragment extends SFragment implements
         return fragment;
     }
 
+    private static final class Placeholder {
+        private final static Placeholder INSTANCE = new Placeholder();
+
+        public static Placeholder getInstance() {
+            return INSTANCE;
+        }
+
+        private Placeholder() {
+        }
+    }
+
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
@@ -179,12 +206,10 @@ public class TimelineFragment extends SFragment implements
             TabLayout layout = getActivity().findViewById(R.id.tab_layout);
             onTabSelectedListener = new TabLayout.OnTabSelectedListener() {
                 @Override
-                public void onTabSelected(TabLayout.Tab tab) {
+                public void onTabSelected(TabLayout.Tab tab) {}
-                }
 
                 @Override
-                public void onTabUnselected(TabLayout.Tab tab) {
+                public void onTabUnselected(TabLayout.Tab tab) {}
-                }
 
                 @Override
                 public void onTabReselected(TabLayout.Tab tab) {
@@ -219,7 +244,7 @@ public class TimelineFragment extends SFragment implements
                         } else if (!composeButton.isShown()) {
                             composeButton.show();
                         }
-                }
+                    }
                 }
 
                 @Override
@@ -251,86 +276,97 @@ public class TimelineFragment extends SFragment implements
 
     @Override
     public void onRefresh() {
-        sendFetchTimelineRequest(null, topId, FetchEnd.TOP);
+        sendFetchTimelineRequest(null, topId, FetchEnd.TOP, -1);
     }
 
     @Override
     public void onReply(int position) {
-        super.reply(statuses.get(position));
+        super.reply(statuses.get(position).getAsRight());
     }
 
     @Override
     public void onReblog(final boolean reblog, final int position) {
-        final Status status = statuses.get(position);
+        final Status status = statuses.get(position).getAsRight();
         super.reblogWithCallback(status, reblog, new Callback<Status>() {
             @Override
-            public void onResponse(@NonNull Call<Status> call, @NonNull retrofit2.Response<Status> response) {
+            public void onResponse(@NonNull Call<Status> call, @NonNull Response<Status> response) {
+
                 if (response.isSuccessful()) {
                     status.reblogged = reblog;
 
                     if (status.reblog != null) {
                         status.reblog.reblogged = reblog;
                     }
+
+                    Pair<StatusViewData.Concrete, Integer> actual =
+                            findStatusAndPosition(position, status);
+                    if (actual == null) return;
+
                     StatusViewData newViewData =
-                            new StatusViewData.Builder(statuses.getPairedItem(position))
+                            new StatusViewData.Builder(actual.first)
                                     .setReblogged(reblog)
                                     .createStatusViewData();
-                    statuses.setPairedItem(position, newViewData);
+                    statuses.setPairedItem(actual.second, newViewData);
-                    adapter.changeItem(position, newViewData, true);
+                    adapter.changeItem(actual.second, newViewData, true);
                 }
             }
 
             @Override
             public void onFailure(@NonNull Call<Status> call, @NonNull Throwable t) {
-                Log.d(TAG, "Failed to reblog status " + status.id);
+                Log.d(TAG, "Failed to reblog status " + status.id, t);
-                t.printStackTrace();
             }
         });
     }
 
     @Override
     public void onFavourite(final boolean favourite, final int position) {
-        final Status status = statuses.get(position);
+        final Status status = statuses.get(position).getAsRight();
 
         super.favouriteWithCallback(status, favourite, new Callback<Status>() {
             @Override
-            public void onResponse(@NonNull Call<Status> call, @NonNull retrofit2.Response<Status> response) {
+            public void onResponse(@NonNull Call<Status> call, @NonNull Response<Status> response) {
+
                 if (response.isSuccessful()) {
                     status.favourited = favourite;
 
                     if (status.reblog != null) {
                         status.reblog.favourited = favourite;
                     }
+
+                    Pair<StatusViewData.Concrete, Integer> actual =
+                            findStatusAndPosition(position, status);
+                    if (actual == null) return;
+
                     StatusViewData newViewData = new StatusViewData
-                            .Builder(statuses.getPairedItem(position))
+                            .Builder(actual.first)
                             .setFavourited(favourite)
                             .createStatusViewData();
-                    statuses.setPairedItem(position, newViewData);
+                    statuses.setPairedItem(actual.second, newViewData);
-                    adapter.changeItem(position, newViewData, true);
+                    adapter.changeItem(actual.second, newViewData, true);
                 }
             }
 
             @Override
             public void onFailure(@NonNull Call<Status> call, @NonNull Throwable t) {
-                Log.d(TAG, "Failed to favourite status " + status.id);
+                Log.d(TAG, "Failed to favourite status " + status.id, t);
-                t.printStackTrace();
             }
         });
     }
 
     @Override
     public void onMore(View view, final int position) {
-        super.more(statuses.get(position), view, position);
+        super.more(statuses.get(position).getAsRight(), view, position);
     }
 
     @Override
     public void onOpenReblog(int position) {
-        super.openReblog(statuses.get(position));
+        super.openReblog(statuses.get(position).getAsRight());
     }
 
     @Override
     public void onExpandedChange(boolean expanded, int position) {
-        StatusViewData newViewData = new StatusViewData.Builder(statuses.getPairedItem(position))
+        StatusViewData newViewData = new StatusViewData.Builder(
+                ((StatusViewData.Concrete) statuses.getPairedItem(position)))
                 .setIsExpanded(expanded).createStatusViewData();
         statuses.setPairedItem(position, newViewData);
         adapter.changeItem(position, newViewData, false);
@@ -338,12 +374,33 @@ public class TimelineFragment extends SFragment implements
 
     @Override
     public void onContentHiddenChange(boolean isShowing, int position) {
-        StatusViewData newViewData = new StatusViewData.Builder(statuses.getPairedItem(position))
+        StatusViewData newViewData = new StatusViewData.Builder(
+                ((StatusViewData.Concrete) statuses.getPairedItem(position)))
                 .setIsShowingSensitiveContent(isShowing).createStatusViewData();
         statuses.setPairedItem(position, newViewData);
         adapter.changeItem(position, newViewData, false);
     }
 
+    @Override
+    public void onLoadMore(int position) {
+        //check bounds before accessing list,
+        if (statuses.size() >= position && position > 0) {
+            Status fromStatus = statuses.get(position - 1).getAsRightOrNull();
+            Status toStatus = statuses.get(position + 1).getAsRightOrNull();
+            if (fromStatus == null || toStatus == null) {
+                Log.e(TAG, "Failed to load more at " + position + ", wrong placeholder position");
+                return;
+            }
+            sendFetchTimelineRequest(fromStatus.id, toStatus.id, FetchEnd.MIDDLE, position);
+
+            StatusViewData newViewData = new StatusViewData.Placeholder(true);
+            statuses.setPairedItem(position, newViewData);
+            adapter.changeItem(position, newViewData, false);
+        } else {
+            Log.e(TAG, "error loading more");
+        }
+    }
+
     @Override
     public void onViewMedia(String[] urls, int urlIndex, Status.MediaAttachment.Type type,
                             View view) {
@@ -352,7 +409,7 @@ public class TimelineFragment extends SFragment implements
 
     @Override
     public void onViewThread(int position) {
-        super.viewThread(statuses.get(position));
+        super.viewThread(statuses.get(position).getAsRight());
     }
 
     @Override
@@ -417,10 +474,10 @@ public class TimelineFragment extends SFragment implements
     @Override
     public void removeAllByAccountId(String accountId) {
         // using iterator to safely remove items while iterating
-        Iterator<Status> iterator = statuses.iterator();
+        Iterator<Either<Placeholder, Status>> iterator = statuses.iterator();
         while (iterator.hasNext()) {
-            Status status = iterator.next();
+            Status status = iterator.next().getAsRightOrNull();
-            if (status.account.id.equals(accountId)) {
+            if (status != null && status.account.id.equals(accountId)) {
                 iterator.remove();
             }
         }
@@ -428,12 +485,12 @@ public class TimelineFragment extends SFragment implements
     }
 
     private void onLoadMore() {
-        sendFetchTimelineRequest(bottomId, null, FetchEnd.BOTTOM);
+        sendFetchTimelineRequest(bottomId, null, FetchEnd.BOTTOM, -1);
     }
 
     private void fullyRefresh() {
         adapter.clear();
-        sendFetchTimelineRequest(null, null, FetchEnd.TOP);
+        sendFetchTimelineRequest(null, null, FetchEnd.TOP, -1);
     }
 
     private boolean jumpToTopAllowed() {
@@ -457,20 +514,20 @@ public class TimelineFragment extends SFragment implements
             case HOME:
                 return api.homeTimeline(fromId, uptoId, null);
             case PUBLIC_FEDERATED:
-                return api.publicTimeline(null, fromId, uptoId, null);
+                return api.publicTimeline(null, fromId, uptoId, LOAD_AT_ONCE);
             case PUBLIC_LOCAL:
-                return api.publicTimeline(true, fromId, uptoId, null);
+                return api.publicTimeline(true, fromId, uptoId, LOAD_AT_ONCE);
             case TAG:
-                return api.hashtagTimeline(tagOrId, null, fromId, uptoId, null);
+                return api.hashtagTimeline(tagOrId, null, fromId, uptoId, LOAD_AT_ONCE);
             case USER:
-                return api.accountStatuses(tagOrId, fromId, uptoId, null, null);
+                return api.accountStatuses(tagOrId, fromId, uptoId, LOAD_AT_ONCE);
             case FAVOURITES:
-                return api.favourites(fromId, uptoId, null);
+                return api.favourites(fromId, uptoId, LOAD_AT_ONCE);
         }
     }
 
     private void sendFetchTimelineRequest(@Nullable String fromId, @Nullable String uptoId,
-                                          final FetchEnd fetchEnd) {
+                                          final FetchEnd fetchEnd, final int pos) {
         /* If there is a fetch already ongoing, record however many fetches are requested and
          * fulfill them after it's complete. */
         if (fetchEnd == FetchEnd.TOP && topLoading) {
@@ -499,15 +556,15 @@ public class TimelineFragment extends SFragment implements
             public void onResponse(@NonNull Call<List<Status>> call, @NonNull Response<List<Status>> response) {
                 if (response.isSuccessful()) {
                     String linkHeader = response.headers().get("Link");
-                    onFetchTimelineSuccess(response.body(), linkHeader, fetchEnd);
+                    onFetchTimelineSuccess(response.body(), linkHeader, fetchEnd, pos);
                 } else {
-                    onFetchTimelineFailure(new Exception(response.message()), fetchEnd);
+                    onFetchTimelineFailure(new Exception(response.message()), fetchEnd, pos);
                 }
             }
 
             @Override
             public void onFailure(@NonNull Call<List<Status>> call, @NonNull Throwable t) {
-                onFetchTimelineFailure((Exception) t, fetchEnd);
+                onFetchTimelineFailure((Exception) t, fetchEnd, pos);
             }
         };
 
@@ -516,8 +573,11 @@ public class TimelineFragment extends SFragment implements
         listCall.enqueue(callback);
     }
 
-    public void onFetchTimelineSuccess(List<Status> statuses, String linkHeader,
+    private void onFetchTimelineSuccess(List<Status> statuses, String linkHeader,
-                                       FetchEnd fetchEnd) {
+                                        FetchEnd fetchEnd, int pos) {
+        // We filled the hole (or reached the end) if the server returned less statuses than we
+        // we asked for.
+        boolean fullFetch = statuses.size() >= LOAD_AT_ONCE;
         filterStatuses(statuses);
         List<HttpHeaderLink> links = HttpHeaderLink.parse(linkHeader);
         switch (fetchEnd) {
@@ -527,7 +587,11 @@ public class TimelineFragment extends SFragment implements
                 if (previous != null) {
                     uptoId = previous.uri.getQueryParameter("since_id");
                 }
-                updateStatuses(statuses, null, uptoId);
+                updateStatuses(statuses, null, uptoId, fullFetch);
+                break;
+            }
+            case MIDDLE: {
+                replacePlaceholderWithStatuses(statuses, fullFetch, pos);
                 break;
             }
             case BOTTOM: {
@@ -547,7 +611,7 @@ public class TimelineFragment extends SFragment implements
                     if (previous != null) {
                         uptoId = previous.uri.getQueryParameter("since_id");
                     }
-                    updateStatuses(statuses, fromId, uptoId);
+                    updateStatuses(statuses, fromId, uptoId, fullFetch);
                 }
                 break;
             }
@@ -561,8 +625,15 @@ public class TimelineFragment extends SFragment implements
         swipeRefreshLayout.setRefreshing(false);
     }
 
-    public void onFetchTimelineFailure(Exception exception, FetchEnd fetchEnd) {
+    private void onFetchTimelineFailure(Exception exception, FetchEnd fetchEnd, int position) {
         swipeRefreshLayout.setRefreshing(false);
+
+        if (fetchEnd == FetchEnd.MIDDLE && !statuses.get(position).isRight()) {
+            StatusViewData newViewData = new StatusViewData.Placeholder(false);
+            statuses.setPairedItem(position, newViewData);
+            adapter.changeItem(position, newViewData, true);
+        }
+
         Log.e(TAG, "Fetch Failure: " + exception.getMessage());
         fulfillAnyQueuedFetches(fetchEnd);
     }
@@ -588,7 +659,7 @@ public class TimelineFragment extends SFragment implements
         }
     }
 
-    protected void filterStatuses(List<Status> statuses) {
+    private void filterStatuses(List<Status> statuses) {
         Iterator<Status> it = statuses.iterator();
         while (it.hasNext()) {
             Status status = it.next();
@@ -600,7 +671,7 @@ public class TimelineFragment extends SFragment implements
     }
 
     private void updateStatuses(List<Status> newStatuses, @Nullable String fromId,
-                                @Nullable String toId) {
+                                @Nullable String toId, boolean fullFetch) {
         if (ListUtils.isEmpty(newStatuses)) {
             return;
         }
@@ -610,20 +681,26 @@ public class TimelineFragment extends SFragment implements
         if (toId != null) {
             topId = toId;
         }
+
+        List<Either<Placeholder, Status>> liftedNew = listStatusList(newStatuses);
+
         if (statuses.isEmpty()) {
-            // This construction removes duplicates while preserving order.
+            statuses.addAll(liftedNew);
-            statuses.addAll(new LinkedHashSet<>(newStatuses));
         } else {
-            Status lastOfNew = newStatuses.get(newStatuses.size() - 1);
+            Either<Placeholder, Status> lastOfNew = liftedNew.get(newStatuses.size() - 1);
             int index = statuses.indexOf(lastOfNew);
+
             for (int i = 0; i < index; i++) {
                 statuses.remove(0);
             }
-            int newIndex = newStatuses.indexOf(statuses.get(0));
+            int newIndex = liftedNew.indexOf(statuses.get(0));
             if (newIndex == -1) {
-                statuses.addAll(0, newStatuses);
+                if (index == -1 && fullFetch) {
+                    liftedNew.add(Either.<Placeholder, Status>left(Placeholder.getInstance()));
+                }
+                statuses.addAll(0, liftedNew);
             } else {
-                statuses.addAll(0, newStatuses.subList(0, newIndex));
+                statuses.addAll(0, liftedNew.subList(0, newIndex));
             }
         }
         adapter.update(statuses.getPairedCopy());
@@ -634,15 +711,17 @@ public class TimelineFragment extends SFragment implements
             return;
         }
         int end = statuses.size();
-        Status last = statuses.get(end - 1);
+        Status last = statuses.get(end - 1).getAsRightOrNull();
+        // I was about to replace findStatus with indexOf but it is incorrect to compare value
+        // types by ID anyway and we should change equals() for Status, I think, so this makes sense
         if (last != null && !findStatus(newStatuses, last.id)) {
-            statuses.addAll(newStatuses);
+            statuses.addAll(listStatusList(newStatuses));
             List<StatusViewData> newViewDatas = statuses.getPairedCopy()
                     .subList(statuses.size() - newStatuses.size(), statuses.size());
             if (BuildConfig.DEBUG && newStatuses.size() != newViewDatas.size()) {
                 String error = String.format(Locale.getDefault(),
                         "Incorrectly got statusViewData sublist." +
-                        " newStatuses.size == %d newViewDatas.size == %d, statuses.size == %d",
+                                " newStatuses.size == %d newViewDatas.size == %d, statuses.size == %d",
                         newStatuses.size(), newViewDatas.size(), statuses.size());
                 throw new AssertionError(error);
             }
@@ -653,6 +732,28 @@ public class TimelineFragment extends SFragment implements
         }
     }
 
+    private void replacePlaceholderWithStatuses(List<Status> newStatuses, boolean fullFetch, int pos) {
+        Status status = statuses.get(pos).getAsRightOrNull();
+        if (status == null) {
+            statuses.remove(pos);
+        }
+
+        if (ListUtils.isEmpty(newStatuses)) {
+            adapter.update(statuses.getPairedCopy());
+            return;
+        }
+
+        List<Either<Placeholder, Status>> liftedNew = listStatusList(newStatuses);
+
+        if (fullFetch) {
+            liftedNew.add(Either.<Placeholder, Status>left(Placeholder.getInstance()));
+        }
+
+        statuses.addAll(pos, liftedNew);
+        adapter.update(statuses.getPairedCopy());
+
+    }
+
     private static boolean findStatus(List<Status> statuses, String id) {
         for (Status status : statuses) {
             if (status.id.equals(id)) {
@@ -661,4 +762,39 @@ public class TimelineFragment extends SFragment implements
         }
         return false;
     }
+
+    private final Function<Status, Either<Placeholder, Status>> statusLifter =
+            new Function<Status, Either<Placeholder, Status>>() {
+                @Override
+                public Either<Placeholder, Status> apply(Status input) {
+                    return Either.right(input);
+                }
+            };
+
+    private @Nullable
+    Pair<StatusViewData.Concrete, Integer>
+    findStatusAndPosition(int position, Status status) {
+        StatusViewData.Concrete statusToUpdate;
+        int positionToUpdate;
+        StatusViewData someOldViewData = statuses.getPairedItem(position);
+
+        // Unlikely, but data could change between the request and response
+        if ((someOldViewData instanceof StatusViewData.Placeholder) ||
+                !((StatusViewData.Concrete) someOldViewData).getId().equals(status.id)) {
+            // try to find the status we need to update
+            int foundPos = statuses.indexOf(Either.<Placeholder, Status>right(status));
+            if (foundPos < 0) return null; // okay, it's hopeless, give up
+            statusToUpdate = ((StatusViewData.Concrete)
+                    statuses.getPairedItem(foundPos));
+            positionToUpdate = position;
+        } else {
+            statusToUpdate = (StatusViewData.Concrete) someOldViewData;
+            positionToUpdate = position;
+        }
+        return new Pair<>(statusToUpdate, positionToUpdate);
+    }
+
+    private List<Either<Placeholder, Status>> listStatusList(List<Status> list) {
+        return CollectionUtil.map(list, statusLifter);
+    }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/ViewThreadFragment.java

@@ -69,7 +69,7 @@ public class ViewThreadFragment extends SFragment implements
 
     private int statusIndex = 0;
 
-    private final PairedList<Status, StatusViewData> statuses =
+    private final PairedList<Status, StatusViewData.Concrete> statuses =
             new PairedList<>(ViewDataUtils.statusMapper());
 
     public static ViewThreadFragment newInstance(String id) {
@@ -83,7 +83,7 @@ public class ViewThreadFragment extends SFragment implements
     @Nullable
     @Override
     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
-            @Nullable Bundle savedInstanceState) {
+                             @Nullable Bundle savedInstanceState) {
         View rootView = inflater.inflate(R.layout.fragment_view_thread, container, false);
 
         Context context = getContext();
@@ -227,22 +227,29 @@ public class ViewThreadFragment extends SFragment implements
 
     @Override
     public void onExpandedChange(boolean expanded, int position) {
-        StatusViewData newViewData = new StatusViewData.Builder(statuses.getPairedItem(position))
+        StatusViewData.Concrete newViewData =
-                .setIsExpanded(expanded)
+                new StatusViewData.Builder(statuses.getPairedItem(position))
-                .createStatusViewData();
+                        .setIsExpanded(expanded)
+                        .createStatusViewData();
         statuses.setPairedItem(position, newViewData);
         adapter.setItem(position, newViewData, false);
     }
 
     @Override
     public void onContentHiddenChange(boolean isShowing, int position) {
-        StatusViewData newViewData = new StatusViewData.Builder(statuses.getPairedItem(position))
+        StatusViewData.Concrete newViewData =
-                .setIsShowingSensitiveContent(isShowing)
+                new StatusViewData.Builder(statuses.getPairedItem(position))
-                .createStatusViewData();
+                        .setIsShowingSensitiveContent(isShowing)
+                        .createStatusViewData();
         statuses.setPairedItem(position, newViewData);
         adapter.setItem(position, newViewData, false);
     }
 
+    @Override
+    public void onLoadMore(int pos) {
+
+    }
+
     @Override
     public void onViewTag(String tag) {
         super.viewTag(tag);
@@ -255,7 +262,7 @@ public class ViewThreadFragment extends SFragment implements
 
     @Override
     public void removeItem(int position) {
-        if(position == statusIndex) {
+        if (position == statusIndex) {
             //the status got removed, close the activity
             getActivity().finish();
         }
@@ -278,7 +285,7 @@ public class ViewThreadFragment extends SFragment implements
             }
         }
         statusIndex = statuses.indexOf(status);
-        if(statusIndex == -1) {
+        if (statusIndex == -1) {
             //the status got removed, close the activity
             getActivity().finish();
             return;
@@ -379,8 +386,8 @@ public class ViewThreadFragment extends SFragment implements
         int i = statusIndex;
         statuses.add(i, status);
         adapter.setDetailedStatusPosition(i);
-        StatusViewData viewData = statuses.getPairedItem(i);
+        StatusViewData.Concrete viewData = statuses.getPairedItem(i);
-        if(viewData.getCard() == null && card != null) {
+        if (viewData.getCard() == null && card != null) {
             viewData = new StatusViewData.Builder(viewData)
                     .setCard(card)
                     .createStatusViewData();
@@ -405,7 +412,7 @@ public class ViewThreadFragment extends SFragment implements
         statusIndex = ancestors.size();
         adapter.setDetailedStatusPosition(statusIndex);
         statuses.addAll(0, ancestors);
-        List<StatusViewData> ancestorsViewDatas = statuses.getPairedCopy().subList(0, statusIndex);
+        List<StatusViewData.Concrete> ancestorsViewDatas = statuses.getPairedCopy().subList(0, statusIndex);
         if (BuildConfig.DEBUG && ancestors.size() != ancestorsViewDatas.size()) {
             String error = String.format(Locale.getDefault(),
                     "Incorrectly got statusViewData sublist." +
@@ -420,8 +427,8 @@ public class ViewThreadFragment extends SFragment implements
             // In case we needed to delete everything (which is way easier than deleting
             // everything except one), re-insert the remaining status here.
             statuses.add(statusIndex, mainStatus);
-            StatusViewData viewData = statuses.getPairedItem(statusIndex);
+            StatusViewData.Concrete viewData = statuses.getPairedItem(statusIndex);
-            if(viewData.getCard() == null && card != null) {
+            if (viewData.getCard() == null && card != null) {
                 viewData = new StatusViewData.Builder(viewData)
                         .setCard(card)
                         .createStatusViewData();
@@ -431,9 +438,9 @@ public class ViewThreadFragment extends SFragment implements
 
         // Insert newly fetched descendants
         statuses.addAll(descendants);
-        List<StatusViewData> descendantsViewData;
+        List<StatusViewData.Concrete> descendantsViewData;
-            descendantsViewData = statuses.getPairedCopy()
+        descendantsViewData = statuses.getPairedCopy()
-                    .subList(statuses.size() - descendants.size(), statuses.size());
+                .subList(statuses.size() - descendants.size(), statuses.size());
         if (BuildConfig.DEBUG && descendants.size() != descendantsViewData.size()) {
             String error = String.format(Locale.getDefault(),
                     "Incorrectly got statusViewData sublist." +
@@ -447,16 +454,14 @@ public class ViewThreadFragment extends SFragment implements
 
     private void showCard(Card card) {
         this.card = card;
-        if(statuses.size() != 0) {
+        if (statuses.size() != 0) {
-            StatusViewData oldViewData = statuses.getPairedItem(statusIndex);
+            StatusViewData.Concrete newViewData =
-                    if(oldViewData != null) {
+                    new StatusViewData.Builder(statuses.getPairedItem(statusIndex))
-                        StatusViewData newViewData = new StatusViewData.Builder(statuses.getPairedItem(statusIndex))
+                            .setCard(card)
-                                .setCard(card)
+                            .createStatusViewData();
-                                .createStatusViewData();
+
-
+            statuses.setPairedItem(statusIndex, newViewData);
-                        statuses.setPairedItem(statusIndex, newViewData);
+            adapter.setItem(statusIndex, newViewData, true);
-                        adapter.setItem(statusIndex, newViewData, true);
-                    }
         }
     }
 

app/src/main/java/com/keylesspalace/tusky/interfaces/StatusActionListener.java

@@ -29,4 +29,5 @@ public interface StatusActionListener extends LinkListener {
     void onOpenReblog(int position);
     void onExpandedChange(boolean expanded, int position);
     void onContentHiddenChange(boolean isShowing, int position);
+    void onLoadMore(int position);
 }

app/src/main/java/com/keylesspalace/tusky/util/CollectionUtil.java

@@ -0,0 +1,38 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+package com.keylesspalace.tusky.util;
+
+import android.arch.core.util.Function;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by charlag on 05/11/17.
+ */
+
+public final class CollectionUtil {
+    private CollectionUtil() {
+        throw new AssertionError();
+    }
+
+    public static <E, R> List<R> map(List<E> list, Function<E, R> mapper) {
+        final List<R> newList = new ArrayList<>(list.size());
+        for (E el : list) {
+            newList.add(mapper.apply(el));
+        }
+        return newList;
+    }
+}

app/src/main/java/com/keylesspalace/tusky/util/Either.java

@@ -0,0 +1,125 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+package com.keylesspalace.tusky.util;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+/**
+ * Created by charlag on 05/11/17.
+ *
+ * Class to represent sum type/tagged union/variant/ADT e.t.c.
+ * It is either Left or Right.
+ */
+public final class Either<L, R> {
+
+    /**
+     * Constructs Left instance of either
+     * @param left Object to be considered Left
+     * @param <L> Left type
+     * @param <R> Right type
+     * @return new instance of Either which contains left.
+     */
+    public static <L, R> Either<L, R> left(L left) {
+        return new Either<>(left, false);
+    }
+
+    /**
+     * Constructs Right instance of either
+     * @param right Object to be considered Right
+     * @param <L> Left type
+     * @param <R> Right type
+     * @return new instance of Either which contains right.
+     */
+    public static <L, R> Either<L, R> right(R right) {
+        return new Either<>(right, true);
+    }
+
+    private final Object value;
+    // we need it because of the types erasure
+    private boolean isRight;
+
+    private Either(Object value, boolean isRight) {
+        this.value = value;
+        this.isRight = isRight;
+    }
+
+    public boolean isRight() {
+        return isRight;
+    }
+
+    /**
+     * Try to get contained object as a Left or throw an exception.
+     * @throws AssertionError If contained value is Right
+     * @return contained value as Right
+     */
+    public @NonNull L getAsLeft() {
+        if (isRight) {
+            throw new AssertionError("Tried to get the Either as Left while it is Right");
+        }
+        //noinspection unchecked
+        return (L) value;
+    }
+
+    /**
+     * Try to get contained object as a Right or throw an exception.
+     * @throws AssertionError If contained value is Left
+     * @return contained value as Right
+     */
+    public @NonNull R getAsRight() {
+        if (!isRight) {
+            throw new AssertionError("Tried to get the Either as Right while it is Left");
+        }
+        //noinspection unchecked
+        return (R) value;
+    }
+
+    /**
+     * Same as {@link #getAsLeft()} but returns {@code null} is the value if Right instead of
+     * throwing an exception.
+     * @return contained value as Left or null
+     */
+    public @Nullable L getAsLeftOrNull() {
+        if (isRight) {
+            return null;
+        }
+        //noinspection unchecked
+        return (L) value;
+    }
+
+    /**
+     * Same as {@link #getAsRightOrNull()} but returns {@code null} is the value if Left instead of
+     * throwing an exception.
+     * @return contained value as Right or null
+     */
+    public @Nullable R getAsRightOrNull() {
+        if (!isRight) {
+            return null;
+        }
+        //noinspection unchecked
+        return (R) value;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null) return false;
+        if (!(obj instanceof Either)) return false;
+        Either that = (Either) obj;
+        return this.isRight == that.isRight &&
+                (this.value == that.value ||
+                        this.value != null && this.value.equals(that.value));
+    }
+}

app/src/main/java/com/keylesspalace/tusky/util/ViewDataUtils.java

@@ -1,3 +1,18 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
 package com.keylesspalace.tusky.util;
 
 import android.arch.core.util.Function;
@@ -17,7 +32,7 @@ import java.util.List;
 
 public final class ViewDataUtils {
     @Nullable
-    public static StatusViewData statusToViewData(@Nullable Status status) {
+    public static StatusViewData.Concrete statusToViewData(@Nullable Status status) {
         if (status == null) return null;
         Status visibleStatus = status.reblog == null ? status : status.reblog;
         return new StatusViewData.Builder().setId(status.id)
@@ -55,12 +70,12 @@ public final class ViewDataUtils {
         return viewDatas;
     }
 
-    public static Function<Status, StatusViewData> statusMapper() {
+    public static Function<Status, StatusViewData.Concrete> statusMapper() {
         return statusMapper;
     }
 
-    public static NotificationViewData notificationToViewData(Notification notification) {
+    public static NotificationViewData.Concrete notificationToViewData(Notification notification) {
-        return new NotificationViewData(notification.type, notification.id, notification.account,
+        return new NotificationViewData.Concrete(notification.type, notification.id, notification.account,
                 statusToViewData(notification.status));
     }
 
@@ -73,10 +88,10 @@ public final class ViewDataUtils {
         return viewDatas;
     }
 
-    private static final Function<Status, StatusViewData> statusMapper =
+    private static final Function<Status, StatusViewData.Concrete> statusMapper =
-            new Function<Status, StatusViewData>() {
+            new Function<Status, StatusViewData.Concrete>() {
                 @Override
-                public StatusViewData apply(Status input) {
+                public StatusViewData.Concrete apply(Status input) {
                     return ViewDataUtils.statusToViewData(input);
                 }
             };

app/src/main/java/com/keylesspalace/tusky/view/ConversationLineItemDecoration.java

@@ -49,16 +49,16 @@ public class ConversationLineItemDecoration extends RecyclerView.ItemDecoration
 
             int position = parent.getChildAdapterPosition(child);
             ThreadAdapter adapter = (ThreadAdapter) parent.getAdapter();
-            StatusViewData current = adapter.getItem(position);
+            StatusViewData.Concrete current = adapter.getItem(position);
             int dividerTop, dividerBottom;
             if (current != null) {
-                StatusViewData above = adapter.getItem(position - 1);
+                StatusViewData.Concrete above = adapter.getItem(position - 1);
                 if (above != null && above.getId().equals(current.getInReplyToId())) {
                     dividerTop = child.getTop();
                 } else {
                     dividerTop = child.getTop() + avatarMargin;
                 }
-                StatusViewData below = adapter.getItem(position + 1);
+                StatusViewData.Concrete below = adapter.getItem(position + 1);
                 if (below != null && current.getId().equals(below.getInReplyToId())) {
                     dividerBottom = child.getBottom();
                 } else {

app/src/main/java/com/keylesspalace/tusky/viewdata/NotificationViewData.java

@@ -1,3 +1,18 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
 package com.keylesspalace.tusky.viewdata;
 
 import com.keylesspalace.tusky.entity.Account;
@@ -5,35 +20,59 @@ import com.keylesspalace.tusky.entity.Notification;
 
 /**
  * Created by charlag on 12/07/2017.
+ *
+ * Class to represent data required to display either a notification or a placeholder.
+ * It is either a {@link Placeholder} or a {@link Concrete}.
+ * It is modelled this way because close relationship between placeholder and concrete notification
+ * is fine in this case. Placeholder case is not modelled as a type of notification because
+ * invariants would be violated and because it would model domain incorrectly. It is prefereable to
+ * {@link com.keylesspalace.tusky.util.Either} because class hierarchy is cheaper, faster and
+ * more native.
  */
-
+public abstract class NotificationViewData {
-public final class NotificationViewData {
+    private NotificationViewData() {
-    private final Notification.Type type;
-    private final String id;
-    private final Account account;
-    private final StatusViewData statusViewData;
-
-    public NotificationViewData(Notification.Type type, String id, Account account,
-                                StatusViewData statusViewData) {
-        this.type = type;
-        this.id = id;
-        this.account = account;
-        this.statusViewData = statusViewData;
     }
 
-    public Notification.Type getType() {
+    public static  final class Concrete extends NotificationViewData {
-        return type;
+        private final Notification.Type type;
-    }
+        private final String id;
+        private final Account account;
+        private final StatusViewData.Concrete statusViewData;
 
-    public String getId() {
+        public Concrete(Notification.Type type, String id, Account account,
-        return id;
+                        StatusViewData.Concrete statusViewData) {
-    }
+            this.type = type;
+            this.id = id;
+            this.account = account;
+            this.statusViewData = statusViewData;
+        }
+
+        public Notification.Type getType() {
+            return type;
+        }
 
-    public Account getAccount() {
+        public String getId() {
-        return account;
+            return id;
+        }
+
+        public Account getAccount() {
+            return account;
+        }
+
+        public StatusViewData.Concrete getStatusViewData() {
+            return statusViewData;
+        }
     }
 
-    public StatusViewData getStatusViewData() {
+    public static final class Placeholder extends NotificationViewData {
-        return statusViewData;
+        private final boolean isLoading;
+
+        public Placeholder(boolean isLoading) {
+            this.isLoading = isLoading;
+        }
+
+        public boolean isLoading() {
+            return isLoading;
+        }
     }
 }

app/src/main/java/com/keylesspalace/tusky/viewdata/StatusViewData.java

@@ -1,3 +1,18 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
 package com.keylesspalace.tusky.viewdata;
 
 import android.support.annotation.Nullable;
@@ -12,179 +27,202 @@ import java.util.List;
 
 /**
  * Created by charlag on 11/07/2017.
+ *
+ * Class to represent data required to display either a notification or a placeholder.
+ * It is either a {@link StatusViewData.Concrete} or a {@link StatusViewData.Placeholder}.
  */
 
-public final class StatusViewData {
+public abstract class StatusViewData {
-    private final String id;
-    private final Spanned content;
-    private final boolean reblogged;
-    private final boolean favourited;
-    @Nullable
-    private final String spoilerText;
-    private final Status.Visibility visibility;
-    private final Status.MediaAttachment[] attachments;
-    @Nullable
-    private final String rebloggedByUsername;
-    @Nullable
-    private final String rebloggedAvatar;
-    private final boolean isSensitive;
-    private final boolean isExpanded;
-    private final boolean isShowingSensitiveContent;
-    private final String userFullName;
-    private final String nickname;
-    private final String avatar;
-    private final Date createdAt;
-    private final String reblogsCount;
-    private final String favouritesCount;
-    @Nullable
-    private final String inReplyToId;
-    // I would rather have something else but it would be too much of a rewrite
-    @Nullable
-    private final Status.Mention[] mentions;
-    private final String senderId;
-    private final boolean rebloggingEnabled;
-    private final Status.Application application;
-    private final List<Status.Emoji> emojis;
-    @Nullable
-    private final Card card;
-
-    public StatusViewData(String id, Spanned content, boolean reblogged, boolean favourited,
-                          String spoilerText, Status.Visibility visibility, Status.MediaAttachment[] attachments,
-                          String rebloggedByUsername, String rebloggedAvatar, boolean sensitive, boolean isExpanded,
-                          boolean isShowingSensitiveWarning, String userFullName, String nickname, String avatar,
-                          Date createdAt, String reblogsCount, String favouritesCount, String inReplyToId,
-                          Status.Mention[] mentions, String senderId, boolean rebloggingEnabled,
-                          Status.Application application, List<Status.Emoji> emojis, Card card) {
-        this.id = id;
-        this.content = content;
-        this.reblogged = reblogged;
-        this.favourited = favourited;
-        this.spoilerText = spoilerText;
-        this.visibility = visibility;
-        this.attachments = attachments;
-        this.rebloggedByUsername = rebloggedByUsername;
-        this.rebloggedAvatar = rebloggedAvatar;
-        this.isSensitive = sensitive;
-        this.isExpanded = isExpanded;
-        this.isShowingSensitiveContent = isShowingSensitiveWarning;
-        this.userFullName = userFullName;
-        this.nickname = nickname;
-        this.avatar = avatar;
-        this.createdAt = createdAt;
-        this.reblogsCount = reblogsCount;
-        this.favouritesCount = favouritesCount;
-        this.inReplyToId = inReplyToId;
-        this.mentions = mentions;
-        this.senderId = senderId;
-        this.rebloggingEnabled = rebloggingEnabled;
-        this.application = application;
-        this.emojis = emojis;
-        this.card = card;
-    }
 
-    public String getId() {
+    private StatusViewData() {
-        return id;
     }
 
-    public Spanned getContent() {
+    public static final class Concrete extends StatusViewData {
-        return content;
+        private final String id;
-    }
+        private final Spanned content;
+        private final boolean reblogged;
+        private final boolean favourited;
+        @Nullable
+        private final String spoilerText;
+        private final Status.Visibility visibility;
+        private final Status.MediaAttachment[] attachments;
+        @Nullable
+        private final String rebloggedByUsername;
+        @Nullable
+        private final String rebloggedAvatar;
+        private final boolean isSensitive;
+        private final boolean isExpanded;
+        private final boolean isShowingSensitiveContent;
+        private final String userFullName;
+        private final String nickname;
+        private final String avatar;
+        private final Date createdAt;
+        private final String reblogsCount;
+        private final String favouritesCount;
+        @Nullable
+        private final String inReplyToId;
+        // I would rather have something else but it would be too much of a rewrite
+        @Nullable
+        private final Status.Mention[] mentions;
+        private final String senderId;
+        private final boolean rebloggingEnabled;
+        private final Status.Application application;
+        private final List<Status.Emoji> emojis;
+        @Nullable
+        private final Card card;
+
+        public Concrete(String id, Spanned content, boolean reblogged, boolean favourited,
+                        @Nullable String spoilerText, Status.Visibility visibility, Status.MediaAttachment[] attachments,
+                        @Nullable String rebloggedByUsername, @Nullable String rebloggedAvatar, boolean sensitive, boolean isExpanded,
+                        boolean isShowingSensitiveWarning, String userFullName, String nickname, String avatar,
+                        Date createdAt, String reblogsCount, String favouritesCount, @Nullable String inReplyToId,
+                        @Nullable Status.Mention[] mentions, String senderId, boolean rebloggingEnabled,
+                        Status.Application application, List<Status.Emoji> emojis, @Nullable Card card) {
+            this.id = id;
+            this.content = content;
+            this.reblogged = reblogged;
+            this.favourited = favourited;
+            this.spoilerText = spoilerText;
+            this.visibility = visibility;
+            this.attachments = attachments;
+            this.rebloggedByUsername = rebloggedByUsername;
+            this.rebloggedAvatar = rebloggedAvatar;
+            this.isSensitive = sensitive;
+            this.isExpanded = isExpanded;
+            this.isShowingSensitiveContent = isShowingSensitiveWarning;
+            this.userFullName = userFullName;
+            this.nickname = nickname;
+            this.avatar = avatar;
+            this.createdAt = createdAt;
+            this.reblogsCount = reblogsCount;
+            this.favouritesCount = favouritesCount;
+            this.inReplyToId = inReplyToId;
+            this.mentions = mentions;
+            this.senderId = senderId;
+            this.rebloggingEnabled = rebloggingEnabled;
+            this.application = application;
+            this.emojis = emojis;
+            this.card = card;
+        }
 
-    public boolean isReblogged() {
+        public String getId() {
-        return reblogged;
+            return id;
-    }
+        }
 
-    public boolean isFavourited() {
+        public Spanned getContent() {
-        return favourited;
+            return content;
-    }
+        }
 
-    @Nullable
+        public boolean isReblogged() {
-    public String getSpoilerText() {
+            return reblogged;
-        return spoilerText;
+        }
-    }
 
-    public Status.Visibility getVisibility() {
+        public boolean isFavourited() {
-        return visibility;
+            return favourited;
-    }
+        }
 
-    public Status.MediaAttachment[] getAttachments() {
+        @Nullable
-        return attachments;
+        public String getSpoilerText() {
-    }
+            return spoilerText;
+        }
 
-    @Nullable
+        public Status.Visibility getVisibility() {
-    public String getRebloggedByUsername() {
+            return visibility;
-        return rebloggedByUsername;
+        }
-    }
 
-    public boolean isSensitive() {
+        public Status.MediaAttachment[] getAttachments() {
-        return isSensitive;
+            return attachments;
-    }
+        }
 
-    public boolean isExpanded() {
+        @Nullable
-        return isExpanded;
+        public String getRebloggedByUsername() {
-    }
+            return rebloggedByUsername;
+        }
 
-    public boolean isShowingSensitiveContent() {
+        public boolean isSensitive() {
-        return isShowingSensitiveContent;
+            return isSensitive;
-    }
+        }
 
-    @Nullable
+        public boolean isExpanded() {
-    public String getRebloggedAvatar() {
+            return isExpanded;
-        return rebloggedAvatar;
+        }
-    }
 
-    public String getUserFullName() {
+        public boolean isShowingSensitiveContent() {
-        return userFullName;
+            return isShowingSensitiveContent;
-    }
+        }
 
-    public String getNickname() {
+        @Nullable
-        return nickname;
+        public String getRebloggedAvatar() {
-    }
+            return rebloggedAvatar;
+        }
 
-    public String getAvatar() {
+        public String getUserFullName() {
-        return avatar;
+            return userFullName;
-    }
+        }
 
-    public Date getCreatedAt() {
+        public String getNickname() {
-        return createdAt;
+            return nickname;
-    }
+        }
 
-    public String getReblogsCount() {
+        public String getAvatar() {
-        return reblogsCount;
+            return avatar;
-    }
+        }
 
-    public String getFavouritesCount() {
+        public Date getCreatedAt() {
-        return favouritesCount;
+            return createdAt;
-    }
+        }
 
-    @Nullable
+        public String getReblogsCount() {
-    public String getInReplyToId() {
+            return reblogsCount;
-        return inReplyToId;
+        }
-    }
 
-    public String getSenderId() {
+        public String getFavouritesCount() {
-        return senderId;
+            return favouritesCount;
-    }
+        }
 
-    public Boolean getRebloggingEnabled() {
+        @Nullable
-        return rebloggingEnabled;
+        public String getInReplyToId() {
-    }
+            return inReplyToId;
+        }
 
-    @Nullable
+        public String getSenderId() {
-    public Status.Mention[] getMentions() {
+            return senderId;
-        return mentions;
+        }
-    }
 
-    public Status.Application getApplication() {
+        public Boolean getRebloggingEnabled() {
-        return application;
+            return rebloggingEnabled;
-    }
+        }
+
+        @Nullable
+        public Status.Mention[] getMentions() {
+            return mentions;
+        }
+
+        public Status.Application getApplication() {
+            return application;
+        }
+
+        public List<Status.Emoji> getEmojis() {
+            return emojis;
+        }
+
+        @Nullable
+        public Card getCard() {
+            return card;
+        }
 
-    public List<Status.Emoji> getEmojis() {
-        return emojis;
     }
 
-    public Card getCard() {
+    public static final class Placeholder extends StatusViewData {
-        return card;
+        private final boolean isLoading;
+
+        public Placeholder(boolean isLoading) {
+            this.isLoading = isLoading;
+        }
+
+        public boolean isLoading() {
+            return isLoading;
+        }
     }
 
     public static class Builder {
@@ -217,7 +255,7 @@ public final class StatusViewData {
         public Builder() {
         }
 
-        public Builder(final StatusViewData viewData) {
+        public Builder(final StatusViewData.Concrete viewData) {
             id = viewData.id;
             content = viewData.content;
             reblogged = viewData.reblogged;
@@ -243,7 +281,6 @@ public final class StatusViewData {
             application = viewData.application;
             emojis = viewData.getEmojis();
             card = viewData.getCard();
-
         }
 
         public Builder setId(String id) {
@@ -371,12 +408,15 @@ public final class StatusViewData {
             return this;
         }
 
-        public StatusViewData createStatusViewData() {
+        public StatusViewData.Concrete createStatusViewData() {
             if (this.emojis == null) emojis = Collections.emptyList();
-            return new StatusViewData(id, content, reblogged, favourited, spoilerText, visibility,
+            if (this.createdAt == null) createdAt = new Date();
+
+            return new StatusViewData.Concrete(id, content, reblogged, favourited, spoilerText, visibility,
                     attachments, rebloggedByUsername, rebloggedAvatar, isSensitive, isExpanded,
                     isShowingSensitiveContent, userFullName, nickname, avatar, createdAt, reblogsCount,
-                    favouritesCount, inReplyToId, mentions, senderId, rebloggingEnabled, application, emojis, card);
+                    favouritesCount, inReplyToId, mentions, senderId, rebloggingEnabled, application,
+                    emojis, card);
         }
     }
 }

app/src/main/res/layout/item_status_placeholder.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Button xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/button_load_more"
+    style="@style/Widget.AppCompat.Button.Borderless"
+    android:layout_width="match_parent"
+    android:layout_height="72dp"
+    android:text="@string/load_more_placeholder_text"
+    android:textColor="?attr/colorAccent" />

app/src/main/res/values/strings.xml

@@ -237,5 +237,6 @@
     <string name="pref_title_alway_show_sensitive_media">Always show all nsfw content</string>
     <string name="title_media">Media</string>
     <string name="replying_to">Replying to @%s</string>
+    <string name="load_more_placeholder_text">load more</string>
 
 </resources>