allow replying to replies

app/src/main/java/awais/instagrabber/fragments/comments/RepliesFragment.java

@@ -174,7 +174,7 @@ public class RepliesFragment extends Fragment {
     }
 
     private void setupToolbar() {
-        binding.toolbar.setTitle("Replies");
+        binding.toolbar.setTitle(R.string.title_replies);
         binding.toolbar.setNavigationIcon(R.drawable.ic_round_arrow_back_24);
         binding.toolbar.setNavigationOnClickListener(v -> {
             final FragmentManager fragmentManager = getParentFragmentManager();
@@ -187,7 +187,16 @@ public class RepliesFragment extends Fragment {
         if (context == null) return;
         commentsAdapter = new CommentsAdapter(currentUserId,
                                               true,
-                                              Helper.getCommentCallback(context, getViewLifecycleOwner(), getNavController(), viewModel, null));
+                                              Helper.getCommentCallback(context,
+                                                      getViewLifecycleOwner(),
+                                                      getNavController(),
+                                                      viewModel,
+                                                      (comment, focusInput) -> {
+                                                           viewModel.setReplyTo(comment);
+                                                           binding.commentText.setText(String.format("@%s ", comment.getUser().getUsername()));
+                                                           if (focusInput) Utils.showKeyboard(binding.commentText);
+                                                           return null;
+                                                      }));
         binding.comments.setAdapter(commentsAdapter);
         final Resource<List<Comment>> listResource = viewModel.getReplyList().getValue();
         commentsAdapter.submitList(listResource != null ? listResource.data : Collections.emptyList());

app/src/main/java/awais/instagrabber/viewmodels/CommentsViewerViewModel.java

@@ -54,7 +54,7 @@ public class CommentsViewerViewModel extends ViewModel {
     private String postId;
     private String rootCursor;
     private boolean rootHasNext = true;
-    private Comment repliesParent;
+    private Comment repliesParent, replyTo;
     private String repliesCursor;
     private boolean repliesHasNext = true;
     private final CommentService commentService;
@@ -153,6 +153,11 @@ public class CommentsViewerViewModel extends ViewModel {
         return repliesParent;
     }
 
+    @Nullable
+    public void setReplyTo(final Comment replyTo) {
+        this.replyTo = replyTo;
+    }
+
     public LiveData<Resource<List<Comment>>> getRootList() {
         return rootList;
     }
@@ -297,6 +302,7 @@ public class CommentsViewerViewModel extends ViewModel {
         if (comment == null) return;
         if (repliesParent == null || !Objects.equals(repliesParent.getPk(), comment.getPk())) {
             repliesParent = comment;
+            replyTo = comment;
             prevReplies = null;
             prevRepliesCursor = null;
             prevRepliesHasNext = true;
@@ -368,8 +374,8 @@ public class CommentsViewerViewModel extends ViewModel {
                                               final boolean isReply) {
         final MutableLiveData<Resource<Object>> data = new MutableLiveData<>(Resource.loading(null));
         String replyToId = null;
-        if (isReply && repliesParent != null) {
-            replyToId = repliesParent.getPk();
+        if (isReply && replyTo != null) {
+            replyToId = replyTo.getPk();
         }
         if (isReply && replyToId == null) {
             data.postValue(Resource.error(null, null));
@@ -399,10 +405,9 @@ public class CommentsViewerViewModel extends ViewModel {
         final List<Comment> list = getPrevList(isReply ? replyList : rootList);
         final ImmutableList.Builder<Comment> builder = ImmutableList.builder();
         if (isReply) {
-            // in a reply list the first comment is the parent comment
-            builder.add(list.get(0))
-                   .add(comment)
-                   .addAll(list.subList(1, list.size()));
+            // replies are added to the bottom of the list to preserve chronological order
+            builder.addAll(list)
+                   .add(comment);
         } else {
             builder.add(comment)
                    .addAll(list);

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

@@ -22,6 +22,7 @@
     <string name="title_favorites">Favorites</string>
     <string name="title_discover">Discover</string>
     <string name="title_comments">Comments</string>
+    <string name="title_replies">Replies</string>
     <string name="title_notifications">Activity</string>
     <string name="update_check">Check for updates at startup</string>
     <string name="flag_secure">Block screenshots &amp; app preview</string>