Load sensitive media previews only when shown (#1439)

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

@@ -29,11 +29,11 @@ import com.keylesspalace.tusky.entity.Emoji;
 import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.util.CustomEmojiHelper;
-import com.keylesspalace.tusky.util.TimestampUtils;
 import com.keylesspalace.tusky.util.HtmlUtils;
 import com.keylesspalace.tusky.util.ImageLoadingHelper;
 import com.keylesspalace.tusky.util.LinkHelper;
 import com.keylesspalace.tusky.util.ThemeUtils;
+import com.keylesspalace.tusky.util.TimestampUtils;
 import com.keylesspalace.tusky.view.MediaPreviewImageView;
 import com.keylesspalace.tusky.viewdata.PollOptionViewData;
 import com.keylesspalace.tusky.viewdata.PollViewData;
@@ -92,6 +92,8 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
     private int avatarRadius36dp;
     private int avatarRadius24dp;
 
+    private final int mediaPreviewUnloadedId;
+
     protected StatusBaseViewHolder(View itemView,
                                    boolean useAbsoluteTime) {
         super(itemView);
@@ -145,6 +147,9 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         this.avatarRadius48dp = itemView.getContext().getResources().getDimensionPixelSize(R.dimen.avatar_radius_48dp);
         this.avatarRadius36dp = itemView.getContext().getResources().getDimensionPixelSize(R.dimen.avatar_radius_36dp);
         this.avatarRadius24dp = itemView.getContext().getResources().getDimensionPixelSize(R.dimen.avatar_radius_24dp);
+
+        mediaPreviewUnloadedId = ThemeUtils.getDrawableId(itemView.getContext(),
+                R.attr.media_preview_unloaded_drawable, android.R.color.black);
     }
 
     protected abstract int getMediaPreviewHeight(Context context);
@@ -329,66 +334,71 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         favouriteButton.setChecked(favourited);
     }
 
-    protected void setMediaPreviews(final List<Attachment> attachments, boolean sensitive,
+    private void loadImage(MediaPreviewImageView imageView, String previewUrl, String description,
-                                    final StatusActionListener listener, boolean showingContent) {
+                           MetaData meta) {
-
-        Context context = itemView.getContext();
-
-        int mediaPreviewUnloadedId =
-                ThemeUtils.getDrawableId(itemView.getContext(), R.attr.media_preview_unloaded_drawable,
-                        android.R.color.black);
-
-        final int n = Math.min(attachments.size(), Status.MAX_MEDIA_ATTACHMENTS);
-
-        for (int i = 0; i < n; i++) {
-            String previewUrl = attachments.get(i).getPreviewUrl();
-            String description = attachments.get(i).getDescription();
-
-            if (TextUtils.isEmpty(description)) {
-                mediaPreviews[i].setContentDescription(context.getString(R.string.action_view_media));
-            } else {
-                mediaPreviews[i].setContentDescription(description);
-            }
-
-            mediaPreviews[i].setVisibility(View.VISIBLE);
-
         if (TextUtils.isEmpty(previewUrl)) {
-                Glide.with(mediaPreviews[i])
+            Glide.with(imageView)
                     .load(mediaPreviewUnloadedId)
                     .centerInside()
-                        .into(mediaPreviews[i]);
+                    .into(imageView);
         } else {
-                MetaData meta = attachments.get(i).getMeta();
             Focus focus = meta != null ? meta.getFocus() : null;
 
             if (focus != null) { // If there is a focal point for this attachment:
-                    mediaPreviews[i].setFocalPoint(focus);
+                imageView.setFocalPoint(focus);
 
-                    Glide.with(mediaPreviews[i])
+                Glide.with(imageView)
                         .load(previewUrl)
                         .placeholder(mediaPreviewUnloadedId)
                         .centerInside()
-                            .addListener(mediaPreviews[i])
+                        .addListener(imageView)
-                            .into(mediaPreviews[i]);
+                        .into(imageView);
             } else {
-                    mediaPreviews[i].removeFocalPoint();
+                imageView.removeFocalPoint();
 
-                    Glide.with(mediaPreviews[i])
+                Glide.with(imageView)
                         .load(previewUrl)
                         .placeholder(mediaPreviewUnloadedId)
                         .centerInside()
-                            .into(mediaPreviews[i]);
+                        .into(imageView);
             }
         }
+    }
+
+    protected void setMediaPreviews(final List<Attachment> attachments, boolean sensitive,
+                                    final StatusActionListener listener, boolean showingContent) {
+        Context context = itemView.getContext();
+        final int n = Math.min(attachments.size(), Status.MAX_MEDIA_ATTACHMENTS);
+
+        for (int i = 0; i < n; i++) {
+            String previewUrl = attachments.get(i).getPreviewUrl();
+            String description = attachments.get(i).getDescription();
+            MediaPreviewImageView imageView = mediaPreviews[i];
+
+            imageView.setVisibility(View.VISIBLE);
+
+            if (TextUtils.isEmpty(description)) {
+                imageView.setContentDescription(imageView.getContext()
+                        .getString(R.string.action_view_media));
+            } else {
+                imageView.setContentDescription(description);
+            }
+
+            if (!sensitive || showingContent) {
+                loadImage(imageView, previewUrl, description, attachments.get(i).getMeta());
+            } else {
+                imageView.setImageResource(mediaPreviewUnloadedId);
+            }
 
             final Attachment.Type type = attachments.get(i).getType();
-            if (type == Attachment.Type.VIDEO | type == Attachment.Type.GIFV) {
+            if (type == Attachment.Type.VIDEO || type == Attachment.Type.GIFV) {
                 mediaOverlays[i].setVisibility(View.VISIBLE);
             } else {
                 mediaOverlays[i].setVisibility(View.GONE);
             }
 
-            setAttachmentClickListener(mediaPreviews[i], listener, i, attachments.get(i), true);
+            setAttachmentClickListener(imageView, listener, i, attachments.get(i), true);
+        }
 
         final int mediaPreviewHeight = getMediaPreviewHeight(context);
 
@@ -401,7 +411,6 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
             mediaPreviews[2].getLayoutParams().height = mediaPreviewHeight;
             mediaPreviews[3].getLayoutParams().height = mediaPreviewHeight;
         }
-        }
 
         final String hiddenContentText;
         if (sensitive) {