The reply button now works, and mentions are highlighted in compose mode.

app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java

@@ -26,7 +26,10 @@ import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
 import android.text.Editable;
+import android.text.Spannable;
+import android.text.Spanned;
 import android.text.TextWatcher;
+import android.text.style.ForegroundColorSpan;
 import android.view.View;
 import android.webkit.MimeTypeMap;
 import android.widget.Button;
@@ -54,19 +57,25 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public class ComposeActivity extends AppCompatActivity {
     private static final int STATUS_CHARACTER_LIMIT = 500;
     private static final int STATUS_MEDIA_SIZE_LIMIT = 4000000; // 4MB
     private static final int MEDIA_PICK_RESULT = 1;
     private static final int PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 1;
+    private static final Pattern mentionPattern = Pattern.compile("\\B@[^\\s@]+@?[^\\s@]+");
 
+    private String inReplyToId;
     private String domain;
     private String accessToken;
     private EditText textEditor;
@@ -148,6 +157,156 @@ public class ComposeActivity extends AppCompatActivity {
         Snackbar.make(findViewById(R.id.activity_compose), stringId, Snackbar.LENGTH_LONG).show();
     }
 
+    private static class Interval {
+        public int start;
+        public int end;
+    }
+
+    private static void colourMentions(Spannable text, int colour) {
+        // Strip all existing colour spans.
+        int n = text.length();
+        ForegroundColorSpan[] oldSpans = text.getSpans(0, n, ForegroundColorSpan.class);
+        for (int i = oldSpans.length - 1; i >= 0; i--) {
+            text.removeSpan(oldSpans[i]);
+        }
+        // Match a list of new colour spans.
+        List<Interval> intervals = new ArrayList<>();
+        Matcher matcher = mentionPattern.matcher(text);
+        while (matcher.find()) {
+            Interval interval = new Interval();
+            interval.start = matcher.start();
+            interval.end = matcher.end();
+            intervals.add(interval);
+        }
+        // Make sure intervals don't overlap.
+        Collections.sort(intervals, new Comparator<Interval>() {
+            @Override
+            public int compare(Interval a, Interval b) {
+                return a.start - b.start;
+            }
+        });
+        for (int i = 0, j = 0; i < intervals.size() - 1; i++, j++) {
+            if (j != 0) {
+                Interval a = intervals.get(j - 1);
+                Interval b = intervals.get(i);
+                if (a.start <= b.end) {
+                    while (j != 0 && a.start <= b.end) {
+                        a = intervals.get(j - 1);
+                        b = intervals.get(i);
+                        a.end = Math.max(a.end, b.end);
+                        a.start = Math.min(a.start, b.start);
+                        j--;
+                    }
+                } else {
+                    intervals.set(j, b);
+                }
+            } else {
+                intervals.set(j, intervals.get(i));
+            }
+        }
+        // Finally, set the spans.
+        for (Interval interval : intervals) {
+            text.setSpan(new ForegroundColorSpan(colour), interval.start, interval.end,
+                    Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
+        }
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_compose);
+
+        Intent intent = getIntent();
+        String[] mentionedUsernames = null;
+        if (intent != null) {
+            inReplyToId = intent.getStringExtra("in_reply_to_id");
+            mentionedUsernames = intent.getStringArrayExtra("mentioned_usernames");
+        }
+
+        SharedPreferences preferences = getSharedPreferences(
+                getString(R.string.preferences_file_key), Context.MODE_PRIVATE);
+        domain = preferences.getString("domain", null);
+        accessToken = preferences.getString("accessToken", null);
+        assert(domain != null);
+        assert(accessToken != null);
+
+        textEditor = (EditText) findViewById(R.id.field_status);
+        final TextView charactersLeft = (TextView) findViewById(R.id.characters_left);
+        final int mentionColour = ContextCompat.getColor(this, R.color.compose_mention);
+        TextWatcher textEditorWatcher = new TextWatcher() {
+            @Override
+            public void onTextChanged(CharSequence s, int start, int before, int count) {
+                int left = STATUS_CHARACTER_LIMIT - s.length();
+                charactersLeft.setText(Integer.toString(left));
+            }
+
+            @Override
+            public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
+
+            @Override
+            public void afterTextChanged(Editable editable) {
+                colourMentions(editable, mentionColour);
+            }
+        };
+        textEditor.addTextChangedListener(textEditorWatcher);
+
+        if (mentionedUsernames != null) {
+            StringBuilder builder = new StringBuilder();
+            for (String name : mentionedUsernames) {
+                builder.append('@');
+                builder.append(name);
+                builder.append(' ');
+            }
+            textEditor.setText(builder);
+            textEditor.setSelection(textEditor.length());
+        }
+
+        mediaPreviewBar = (LinearLayout) findViewById(R.id.compose_media_preview_bar);
+        mediaQueued = new ArrayList<>();
+        waitForMediaLatch = new CountUpDownLatch();
+
+        final RadioGroup radio = (RadioGroup) findViewById(R.id.radio_visibility);
+        final Button sendButton = (Button) findViewById(R.id.button_send);
+        sendButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                Editable editable = textEditor.getText();
+                if (editable.length() <= STATUS_CHARACTER_LIMIT) {
+                    int id = radio.getCheckedRadioButtonId();
+                    String visibility;
+                    switch (id) {
+                        default:
+                        case R.id.radio_public: {
+                            visibility = "public";
+                            break;
+                        }
+                        case R.id.radio_unlisted: {
+                            visibility = "unlisted";
+                            break;
+                        }
+                        case R.id.radio_private: {
+                            visibility = "private";
+                            break;
+                        }
+                    }
+                    readyStatus(editable.toString(), visibility, markSensitive.isChecked());
+                } else {
+                    textEditor.setError(getString(R.string.error_compose_character_limit));
+                }
+            }
+        });
+
+        mediaPick = (ImageButton) findViewById(R.id.compose_photo_pick);
+        mediaPick.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                onMediaPick();
+            }
+        });
+        markSensitive = (CheckBox) findViewById(R.id.compose_mark_sensitive);
+        markSensitive.setVisibility(View.GONE);
+    }
+
     private void onSendSuccess() {
         Toast.makeText(this, "Toot!", Toast.LENGTH_SHORT).show();
         finish();
@@ -165,6 +324,9 @@ public class ComposeActivity extends AppCompatActivity {
             parameters.put("status", content);
             parameters.put("visibility", visibility);
             parameters.put("sensitive", sensitive);
+            if (inReplyToId != null) {
+                parameters.put("in_reply_to_id", inReplyToId);
+            }
             JSONArray media_ids = new JSONArray();
             for (QueuedMedia item : mediaQueued) {
                 media_ids.put(item.getId());
@@ -257,81 +419,6 @@ public class ComposeActivity extends AppCompatActivity {
                 });
     }
 
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_compose);
-
-        SharedPreferences preferences = getSharedPreferences(
-                getString(R.string.preferences_file_key), Context.MODE_PRIVATE);
-        domain = preferences.getString("domain", null);
-        accessToken = preferences.getString("accessToken", null);
-        assert(domain != null);
-        assert(accessToken != null);
-
-        textEditor = (EditText) findViewById(R.id.field_status);
-        final TextView charactersLeft = (TextView) findViewById(R.id.characters_left);
-        TextWatcher textEditorWatcher = new TextWatcher() {
-            @Override
-            public void onTextChanged(CharSequence s, int start, int before, int count) {
-                int left = STATUS_CHARACTER_LIMIT - s.length();
-                charactersLeft.setText(Integer.toString(left));
-            }
-
-            @Override
-            public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
-
-            @Override
-            public void afterTextChanged(Editable s) {}
-        };
-        textEditor.addTextChangedListener(textEditorWatcher);
-
-        mediaPreviewBar = (LinearLayout) findViewById(R.id.compose_media_preview_bar);
-        mediaQueued = new ArrayList<>();
-        waitForMediaLatch = new CountUpDownLatch();
-
-        final RadioGroup radio = (RadioGroup) findViewById(R.id.radio_visibility);
-        final Button sendButton = (Button) findViewById(R.id.button_send);
-        sendButton.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                Editable editable = textEditor.getText();
-                if (editable.length() <= STATUS_CHARACTER_LIMIT) {
-                    int id = radio.getCheckedRadioButtonId();
-                    String visibility;
-                    switch (id) {
-                        default:
-                        case R.id.radio_public: {
-                            visibility = "public";
-                            break;
-                        }
-                        case R.id.radio_unlisted: {
-                            visibility = "unlisted";
-                            break;
-                        }
-                        case R.id.radio_private: {
-                            visibility = "private";
-                            break;
-                        }
-                    }
-                    readyStatus(editable.toString(), visibility, markSensitive.isChecked());
-                } else {
-                    textEditor.setError(getString(R.string.error_compose_character_limit));
-                }
-            }
-        });
-
-        mediaPick = (ImageButton) findViewById(R.id.compose_photo_pick);
-        mediaPick.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                onMediaPick();
-            }
-        });
-        markSensitive = (CheckBox) findViewById(R.id.compose_mark_sensitive);
-        markSensitive.setVisibility(View.GONE);
-    }
-
     private void onMediaPick() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN &&
                 ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
@@ -468,11 +555,10 @@ public class ComposeActivity extends AppCompatActivity {
 
     private void downsizeMedia(final QueuedMedia item) {
         item.setReadyStage(QueuedMedia.ReadyStage.DOWNSIZING);
-        InputStream stream = null;
+        InputStream stream;
         try {
             stream = getContentResolver().openInputStream(item.getUri());
         } catch (FileNotFoundException e) {
-            IOUtils.closeQuietly(stream);
             onMediaDownsizeFailure(item);
             return;
         }
@@ -567,11 +653,10 @@ public class ComposeActivity extends AppCompatActivity {
             public DataItem getData() {
                 byte[] content = item.getContent();
                 if (content == null) {
-                    InputStream stream = null;
+                    InputStream stream;
                     try {
                         stream = getContentResolver().openInputStream(item.getUri());
                     } catch (FileNotFoundException e) {
-                        IOUtils.closeQuietly(stream);
                         return null;
                     }
                     content = inputStreamGetBytes(stream);
@@ -638,11 +723,10 @@ public class ComposeActivity extends AppCompatActivity {
                         break;
                     }
                     case "image": {
-                        InputStream stream = null;
+                        InputStream stream;
                         try {
                             stream = contentResolver.openInputStream(uri);
                         } catch (FileNotFoundException e) {
-                            IOUtils.closeQuietly(stream);
                             displayTransientError(R.string.error_media_upload_opening);
                             return;
                         }

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

@@ -43,6 +43,7 @@ public class Status {
     private boolean favourited;
     private Visibility visibility;
     private MediaAttachment[] attachments;
+    private Mention[] mentions;
     private boolean sensitive;
 
     public static final int MAX_MEDIA_ATTACHMENTS = 4;
@@ -61,6 +62,7 @@ public class Status {
         this.favourited = favourited;
         this.visibility = Visibility.valueOf(visibility.toUpperCase());
         this.attachments = new MediaAttachment[0];
+        this.mentions = new Mention[0];
     }
 
     public String getId() {
@@ -111,6 +113,10 @@ public class Status {
         return attachments;
     }
 
+    public Mention[] getMentions() {
+        return mentions;
+    }
+
     public boolean getSensitive() {
         return sensitive;
     }
@@ -127,6 +133,10 @@ public class Status {
         this.favourited = favourited;
     }
 
+    public void setMentions(Mention[] mentions) {
+        this.mentions = mentions;
+    }
+
     public void setAttachments(MediaAttachment[] attachments, boolean sensitive) {
         this.attachments = attachments;
         this.sensitive = sensitive;
@@ -196,6 +206,20 @@ public class Status {
         String username = account.getString("acct");
         String avatar = account.getString("avatar");
 
+        JSONArray mentionsArray = object.getJSONArray("mentions");
+        Mention[] mentions = null;
+        if (mentionsArray != null) {
+            int n = mentionsArray.length();
+            mentions = new Mention[n];
+            for (int i = 0; i < n; i++) {
+                JSONObject mention = mentionsArray.getJSONObject(i);
+                String url = mention.getString("url");
+                String mentionedUsername = mention.getString("acct");
+                String mentionedAccountId = mention.getString("id");
+                mentions[i] = new Mention(url, mentionedUsername, mentionedAccountId);
+            }
+        }
+
         JSONArray mediaAttachments = object.getJSONArray("media_attachments");
         MediaAttachment[] attachments = null;
         if (mediaAttachments != null) {
@@ -230,10 +254,13 @@ public class Status {
             status = new Status(
                     id, accountId, displayName, username, contentPlus, avatar, createdAt,
                     reblogged, favourited, visibility);
+            if (mentions != null) {
+                status.setMentions(mentions);
             }
             if (attachments != null) {
                 status.setAttachments(attachments, sensitive);
             }
+        }
         return status;
     }
 
@@ -274,4 +301,28 @@ public class Status {
             return type;
         }
     }
+
+    public static class Mention {
+        private String url;
+        private String username;
+        private String id;
+
+        public Mention(String url, String username, String id) {
+            this.url = url;
+            this.username = username;
+            this.id = id;
+        }
+
+        public String getUrl() {
+            return url;
+        }
+
+        public String getUsername() {
+            return username;
+        }
+
+        public String getId() {
+            return id;
+        }
+    }
 }

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

@@ -3,6 +3,7 @@ package com.keylesspalace.tusky;
 import android.view.View;
 
 public interface StatusActionListener {
+    void onReply(int position);
     void onReblog(final boolean reblog, final int position);
     void onFavourite(final boolean favourite, final int position);
     void onMore(View view, final int position);

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

@@ -347,6 +347,12 @@ public class TimelineAdapter extends RecyclerView.Adapter {
         }
 
         public void setupButtons(final StatusActionListener listener, final int position) {
+            replyButton.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    listener.onReply(position);
+                }
+            });
             reblogButton.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {

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

@@ -31,6 +31,7 @@ import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -46,7 +47,10 @@ public class TimelineFragment extends Fragment implements
 
     private String domain = null;
     private String accessToken = null;
+    /** ID of the account that is currently logged-in. */
     private String userAccountId = null;
+    /** Username of the account that is currently logged-in. */
+    private String userUsername = null;
     private SwipeRefreshLayout swipeRefreshLayout;
     private RecyclerView recyclerView;
     private TimelineAdapter adapter;
@@ -149,6 +153,7 @@ public class TimelineFragment extends Fragment implements
                     public void onResponse(JSONObject response) {
                         try {
                             userAccountId = response.getString("id");
+                            userUsername = response.getString("acct");
                         } catch (JSONException e) {
                             //TODO: Help
                             assert(false);
@@ -273,6 +278,22 @@ public class TimelineFragment extends Fragment implements
         sendRequest(Request.Method.POST, endpoint, null, null);
     }
 
+    public void onReply(int position) {
+        Status status = adapter.getItem(position);
+        String inReplyToId = status.getId();
+        Status.Mention[] mentions = status.getMentions();
+        List<String> mentionedUsernames = new ArrayList<>();
+        for (int i = 0; i < mentions.length; i++) {
+            mentionedUsernames.add(mentions[i].getUsername());
+        }
+        mentionedUsernames.add(status.getUsername());
+        mentionedUsernames.remove(userUsername);
+        Intent intent = new Intent(getContext(), ComposeActivity.class);
+        intent.putExtra("in_reply_to_id", inReplyToId);
+        intent.putExtra("mentioned_usernames", mentionedUsernames.toArray(new String[0]));
+        startActivity(intent);
+    }
+
     public void onReblog(final boolean reblog, final int position) {
         final Status status = adapter.getItem(position);
         String id = status.getId();

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

@@ -7,4 +7,5 @@
     <color name="view_video_background">#000000</color>
     <color name="sensitive_media_warning_background">#303030</color>
     <color name="media_preview_unloaded_background">#DFDFDF</color>
+    <color name="compose_mention">#4F5F6F</color>
 </resources>