Retain comments after orientation changes in ViewPostDetailActivity.

app/src/main/java/SubredditDatabase/SubredditViewModel.java

@@ -37,8 +37,9 @@ public class SubredditViewModel extends AndroidViewModel {
             this.subredditName = subredditName;
         }
 
+        @NonNull
         @Override
-        public <T extends ViewModel> T create(Class<T> modelClass) {
+        public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
             //noinspection unchecked
             return (T) new SubredditViewModel(mApplication, subredditName);
         }

app/src/main/java/ml/docilealligator/infinityforreddit/CommentDataSource.java

@@ -1,189 +0,0 @@
-package ml.docilealligator.infinityforreddit;
-
-import androidx.annotation.NonNull;
-import androidx.lifecycle.MutableLiveData;
-import androidx.paging.PageKeyedDataSource;
-
-import java.util.Locale;
-
-import retrofit2.Retrofit;
-
-public class CommentDataSource extends PageKeyedDataSource<String, Post> {
-    interface OnCommentFetchedCallback {
-        void hasComment();
-        void noComment();
-    }
-
-    private Retrofit retrofit;
-    private Locale locale;
-    private String subredditNamePrefixed;
-    private String article;
-    private String comment;
-    private boolean isPost;
-    private OnCommentFetchedCallback onCommentFetchedCallback;
-
-    private MutableLiveData<NetworkState> paginationNetworkStateLiveData;
-    private MutableLiveData<NetworkState> initialLoadStateLiveData;
-
-    private LoadInitialParams<String> initialParams;
-    private LoadInitialCallback<String, Post> initialCallback;
-    private LoadParams<String> params;
-    private LoadCallback<String, Post> callback;
-
-    private String mParentId;
-
-    CommentDataSource(Retrofit retrofit, Locale locale, String subredditNamePrefixed, String article,
-                      String comment, boolean isPost, OnCommentFetchedCallback onCommentFetchedCallback) {
-        this.retrofit = retrofit;
-        this.locale = locale;
-        this.subredditNamePrefixed = subredditNamePrefixed;
-        this.article = article;
-        this.comment = comment;
-        this.isPost = isPost;
-        paginationNetworkStateLiveData = new MutableLiveData();
-        initialLoadStateLiveData = new MutableLiveData();
-        this.onCommentFetchedCallback = onCommentFetchedCallback;
-    }
-
-    MutableLiveData getPaginationNetworkStateLiveData() {
-        return paginationNetworkStateLiveData;
-    }
-
-    MutableLiveData getInitialLoadStateLiveData() {
-        return initialLoadStateLiveData;
-    }
-
-    @Override
-    public void loadInitial(@NonNull LoadInitialParams<String> params, @NonNull LoadInitialCallback<String, Post> callback) {
-        initialParams = params;
-        initialCallback = callback;
-
-        initialLoadStateLiveData.postValue(NetworkState.LOADING);
-
-        RedditAPI api = retrofit.create(RedditAPI.class);
-
-        //Call<String> comments = api.getComments(subredditNamePrefixed, article, comment);
-        /*comments.enqueue(new Callback<String>() {
-            @Override
-            public void onResponse(@NonNull Call<String> call, @NonNull Response<String> response) {
-                if(response.isSuccessful()) {
-                    ParseComment.parseComment(response.body(), new ArrayList<>(), locale, isPost,
-                            0, new ParseComment.ParseCommentListener() {
-                                @Override
-                                public void onParseCommentSuccess(List<?> commentData, String parentId,
-                                                                  String commaSeparatedChildren) {
-                                    if(commentData.size() > 0) {
-                                        onCommentFetchedCallback.hasComment();
-                                        mParentId = parentId;
-                                    } else {
-                                        onCommentFetchedCallback.noComment();
-                                    }
-
-                                    callback.onResult((List<Post>) commentData, null, commaSeparatedChildren);
-                                    initialLoadStateLiveData.postValue(NetworkState.LOADED);
-                                }
-
-                                @Override
-                                public void onParseCommentFailed() {
-                                    initialLoadStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, "Error parsing comment"));
-                                }
-                            });
-                } else {
-                    Log.i("comment call failed", response.message());
-                    initialLoadStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, "Error parsing comment"));
-                }
-            }
-
-            @Override
-            public void onFailure(@NonNull Call<String> call, @NonNull Throwable t) {
-                initialLoadStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, "Error fetching comment"));
-            }
-        });*/
-    }
-
-    @Override
-    public void loadBefore(@NonNull LoadParams<String> params, @NonNull LoadCallback<String, Post> callback) {
-
-    }
-
-    @Override
-    public void loadAfter(@NonNull LoadParams<String> params, @NonNull LoadCallback<String, Post> callback) {
-        this.params = params;
-        this.callback = callback;
-
-        if(params.key.equals("null") || params.key.equals("")) {
-            return;
-        }
-
-        paginationNetworkStateLiveData.postValue(NetworkState.LOADING);
-
-        RedditAPI api = retrofit.create(RedditAPI.class);
-
-        //Call<String> moreChildrenBasicInfo = api.getMoreChildren(mParentId, params.key);
-        /*moreChildrenBasicInfo.enqueue(new Callback<String>() {
-            @Override
-            public void onResponse(Call<String> call, Response<String> response) {
-                if(response.isSuccessful()) {
-                    ParseComment.parseMoreCommentBasicInfo(response.body(), new ParseComment.ParseMoreCommentBasicInfoListener() {
-                        @Override
-                        public void onParseMoreCommentBasicInfoSuccess(String commaSeparatedChildrenId) {
-                            Call<String> moreComments = api.getInfo(subredditNamePrefixed, commaSeparatedChildrenId);
-                            moreComments.enqueue(new Callback<String>() {
-                                @Override
-                                public void onResponse(Call<String> call, Response<String> response) {
-                                    if(response.isSuccessful()) {
-                                        ParseComment.parseMoreComment(response.body(), new ArrayList<>(), locale,
-                                                0, new ParseComment.ParseCommentListener() {
-                                                    @Override
-                                                    public void onParseCommentSuccess(List<?> commentData, String parentId,
-                                                                                      String commaSeparatedChildren) {
-                                                        callback.onResult((List<Post>) commentData, null);
-                                                        paginationNetworkStateLiveData.postValue(NetworkState.LOADED);
-                                                    }
-
-                                                    @Override
-                                                    public void onParseCommentFailed() {
-                                                        paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, "Error parsing data"));
-                                                    }
-                                                });
-                                    } else {
-                                        Log.i("comment call failed", response.message());
-                                        paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
-                                    }
-                                }
-
-                                @Override
-                                public void onFailure(Call<String> call, Throwable t) {
-                                    String errorMessage = t == null ? "unknown error" : t.getMessage();
-                                    paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, errorMessage));
-                                }
-                            });
-                        }
-
-                        @Override
-                        public void onParseMoreCommentBasicInfoFailed() {
-                            paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, "Parse more comments basic info failed"));
-                        }
-                    });
-                } else {
-                    Log.i("comment call failed", response.message());
-                    paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, response.message()));
-                }
-            }
-
-            @Override
-            public void onFailure(Call<String> call, Throwable t) {
-                String errorMessage = t == null ? "unknown error" : t.getMessage();
-                paginationNetworkStateLiveData.postValue(new NetworkState(NetworkState.Status.FAILED, errorMessage));
-            }
-        });*/
-    }
-
-    void retry() {
-        loadInitial(initialParams, initialCallback);
-    }
-
-    void retryLoadingMore() {
-        loadAfter(params, callback);
-    }
-}

app/src/main/java/ml/docilealligator/infinityforreddit/CommentDataSourceFactory.java

@@ -1,49 +0,0 @@
-package ml.docilealligator.infinityforreddit;
-
-import androidx.lifecycle.MutableLiveData;
-import androidx.paging.DataSource;
-
-import java.util.Locale;
-
-import retrofit2.Retrofit;
-
-public class CommentDataSourceFactory extends DataSource.Factory {
-    private Retrofit retrofit;
-    private Locale locale;
-    private String subredditNamePrefixed;
-    private String article;
-    private String comment;
-    private boolean isPost;
-    private CommentDataSource.OnCommentFetchedCallback onCommentFetchedCallback;
-
-    private CommentDataSource commentDataSource;
-    private MutableLiveData<CommentDataSource> commentDataSourceMutableLiveData;
-
-    CommentDataSourceFactory(Retrofit retrofit, Locale locale, String subredditNamePrefixed,
-                             String article, String comment, boolean isPost,
-                             CommentDataSource.OnCommentFetchedCallback onCommentFetchedCallback) {
-        this.retrofit = retrofit;
-        this.locale = locale;
-        this.subredditNamePrefixed = subredditNamePrefixed;
-        this.article = article;
-        this.comment = comment;
-        this.isPost = isPost;
-        commentDataSourceMutableLiveData = new MutableLiveData<>();
-        this.onCommentFetchedCallback = onCommentFetchedCallback;
-    }
-
-    @Override
-    public DataSource create() {
-        commentDataSource = new CommentDataSource(retrofit, locale, subredditNamePrefixed, article, comment, isPost, onCommentFetchedCallback);
-        commentDataSourceMutableLiveData.postValue(commentDataSource);
-        return commentDataSource;
-    }
-
-    public MutableLiveData<CommentDataSource> getCommentDataSourceMutableLiveData() {
-        return commentDataSourceMutableLiveData;
-    }
-
-    CommentDataSource getCommentDataSource() {
-        return commentDataSource;
-    }
-}

app/src/main/java/ml/docilealligator/infinityforreddit/CommentRecyclerViewAdapter.java

@@ -604,6 +604,10 @@ class CommentRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewH
         notifyItemChanged(mVisibleComments.size() + 1);
     }
 
+    ArrayList<CommentData> getVisibleComments() {
+        return mVisibleComments;
+    }
+
     @Override
     public void onViewRecycled(@NonNull RecyclerView.ViewHolder holder) {
         if (holder instanceof CommentViewHolder) {

app/src/main/java/ml/docilealligator/infinityforreddit/CommentViewModel.java

@@ -1,90 +0,0 @@
-package ml.docilealligator.infinityforreddit;
-
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.Transformations;
-import androidx.lifecycle.ViewModel;
-import androidx.lifecycle.ViewModelProvider;
-import androidx.paging.LivePagedListBuilder;
-import androidx.paging.PagedList;
-import androidx.annotation.NonNull;
-
-import java.util.Locale;
-
-import retrofit2.Retrofit;
-
-public class CommentViewModel extends ViewModel {
-    private CommentDataSourceFactory commentDataSourceFactory;
-    private LiveData<NetworkState> paginationNetworkState;
-    private LiveData<NetworkState> initialLoadingState;
-    private LiveData<PagedList<CommentData>> comments;
-
-    public CommentViewModel(Retrofit retrofit, Locale locale, String subredditNamePrefixed,
-                            String article, String comment, boolean isPost,
-                            CommentDataSource.OnCommentFetchedCallback onCommentFetchedCallback) {
-        commentDataSourceFactory = new CommentDataSourceFactory(retrofit, locale, subredditNamePrefixed, article, comment, isPost, onCommentFetchedCallback);
-
-        initialLoadingState = Transformations.switchMap(commentDataSourceFactory.getCommentDataSourceMutableLiveData(),
-                dataSource -> dataSource.getInitialLoadStateLiveData());
-        paginationNetworkState = Transformations.switchMap(commentDataSourceFactory.getCommentDataSourceMutableLiveData(),
-                dataSource -> dataSource.getPaginationNetworkStateLiveData());
-        PagedList.Config pagedListConfig =
-                (new PagedList.Config.Builder())
-                        .setEnablePlaceholders(false)
-                        .setPageSize(25)
-                        .build();
-
-        comments = (new LivePagedListBuilder(commentDataSourceFactory, pagedListConfig)).build();
-    }
-
-    LiveData<PagedList<CommentData>> getComments() {
-        return comments;
-    }
-
-    LiveData<NetworkState> getPaginationNetworkState() {
-        return paginationNetworkState;
-    }
-
-    LiveData<NetworkState> getInitialLoadingState() {
-        return initialLoadingState;
-    }
-
-    void refresh() {
-        commentDataSourceFactory.getCommentDataSource().invalidate();
-    }
-
-    void retry() {
-        commentDataSourceFactory.getCommentDataSource().retry();
-    }
-
-    void retryLoadingMore() {
-        commentDataSourceFactory.getCommentDataSource().retryLoadingMore();
-    }
-
-    public static class Factory extends ViewModelProvider.NewInstanceFactory {
-        private Retrofit retrofit;
-        private Locale locale;
-        private String subredditNamePrefixed;
-        private String article;
-        private String comment;
-        private boolean isPost;
-        private CommentDataSource.OnCommentFetchedCallback onCommentFetchedCallback;
-
-        public Factory(Retrofit retrofit, Locale locale, String subredditNamePrefixed,
-                       String article, String comment, boolean isPost,
-                       CommentDataSource.OnCommentFetchedCallback onCommentFetchedCallback) {
-            this.retrofit = retrofit;
-            this.locale = locale;
-            this.subredditNamePrefixed = subredditNamePrefixed;
-            this.article = article;
-            this.comment = comment;
-            this.isPost = isPost;
-            this.onCommentFetchedCallback = onCommentFetchedCallback;
-        }
-
-        @NonNull
-        @Override
-        public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
-            return (T) new CommentViewModel(retrofit, locale, subredditNamePrefixed, article, comment, isPost, onCommentFetchedCallback);
-        }
-    }
-}

app/src/main/java/ml/docilealligator/infinityforreddit/ViewPostDetailActivity.java

@@ -49,6 +49,11 @@ public class ViewPostDetailActivity extends AppCompatActivity {
     private static final String ORIENTATION_STATE = "OS";
     private static final String POST_STATE = "PS";
     private static final String IS_REFRESHING_STATE = "IRS";
+    private static final String IS_LOADING_MORE_CHILDREN_STATE = "ILMCS";
+    private static final String COMMENTS_STATE = "CS";
+    private static final String HAS_MORE_CHILDREN_STATE = "HMCS";
+    private static final String MORE_CHILDREN_LIST_STATE = "MCLS";
+    private static final String MORE_CHILDREN_STARTING_INDEX_STATE = "MCSIS";
 
     private Post mPost;
     private int postListPosition = -1;
@@ -58,6 +63,7 @@ public class ViewPostDetailActivity extends AppCompatActivity {
     private ArrayList<String> children;
     private int mChildrenStartingIndex = 0;
     private boolean loadMoreChildrenSuccess = true;
+    private boolean hasMoreChildren;
 
     private LinearLayoutManager mLinearLayoutManager;
     private CommentRecyclerViewAdapter mAdapter;
@@ -128,14 +134,24 @@ public class ViewPostDetailActivity extends AppCompatActivity {
             if(isRefreshing) {
                 isRefreshing = false;
                 refresh();
+            } else {
+                mAdapter.addComments(savedInstanceState.getParcelableArrayList(COMMENTS_STATE),
+                        savedInstanceState.getBoolean(HAS_MORE_CHILDREN_STATE));
+                isLoadingMoreChildren = savedInstanceState.getBoolean(IS_LOADING_MORE_CHILDREN_STATE);
+                children = savedInstanceState.getStringArrayList(MORE_CHILDREN_LIST_STATE);
+                mChildrenStartingIndex = savedInstanceState.getInt(MORE_CHILDREN_STARTING_INDEX_STATE);
+                if(isLoadingMoreChildren) {
+                    isLoadingMoreChildren = false;
+                    fetchMoreComments();
                 }
             }
+        } else {
+            fetchComment();
+        }
 
         if(getIntent().hasExtra(EXTRA_POST_LIST_POSITION)) {
             postListPosition = getIntent().getExtras().getInt(EXTRA_POST_LIST_POSITION);
         }
-
-        fetchComment();
     }
 
     private void fetchComment() {
@@ -148,7 +164,8 @@ public class ViewPostDetailActivity extends AppCompatActivity {
                                                       String parentId, ArrayList<String> children) {
                         ViewPostDetailActivity.this.children = children;
 
-                        mAdapter.addComments(expandedComments, children.size() != 0);
+                        hasMoreChildren = children.size() != 0;
+                        mAdapter.addComments(expandedComments, hasMoreChildren);
 
                         if(children.size() > 0) {
                             mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@@ -219,7 +236,8 @@ public class ViewPostDetailActivity extends AppCompatActivity {
                 0, mLocale, new FetchComment.FetchMoreCommentListener() {
                     @Override
                     public void onFetchMoreCommentSuccess(ArrayList<CommentData> expandedComments, int childrenStartingIndex) {
-                        mAdapter.addComments(expandedComments, childrenStartingIndex < children.size());
+                        hasMoreChildren = childrenStartingIndex < children.size();
+                        mAdapter.addComments(expandedComments, hasMoreChildren);
                         mChildrenStartingIndex = childrenStartingIndex;
                         isLoadingMoreChildren = false;
                         loadMoreChildrenSuccess = true;
@@ -322,6 +340,11 @@ public class ViewPostDetailActivity extends AppCompatActivity {
         outState.putInt(ORIENTATION_STATE, orientation);
         outState.putParcelable(POST_STATE, mPost);
         outState.putBoolean(IS_REFRESHING_STATE, isRefreshing);
+        outState.putBoolean(IS_LOADING_MORE_CHILDREN_STATE, isLoadingMoreChildren);
+        outState.putParcelableArrayList(COMMENTS_STATE, mAdapter.getVisibleComments());
+        outState.putBoolean(HAS_MORE_CHILDREN_STATE, hasMoreChildren);
+        outState.putStringArrayList(MORE_CHILDREN_LIST_STATE, children);
+        outState.putInt(MORE_CHILDREN_STARTING_INDEX_STATE, mChildrenStartingIndex);
     }
 
     @Override