Hide the FloatingActionButton in ViewPostDetailActivity when scrolling down but not when scroll down comments by clicking the volume down key or the fab. Fixed more comments cannot be fetched after orientation change in ViewPostDetailActivity.

1 files changed, 88 insertions, 0 deletions

diff --git a/app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewPostDetailActivity.java b/app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewPostDetailActivity.java
index 11b99830..691eef31 100644
--- a/app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewPostDetailActivity.java
+++ b/app/src/main/java/ml/docilealligator/infinityforreddit/Activity/ViewPostDetailActivity.java
@@ -170,6 +170,7 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
     private boolean showToast = false;
     private boolean isSortingComments = false;
     private boolean mVolumeKeysNavigateComments;
+    private boolean mIsSmoothScrolling = false;
     private LinearLayoutManager mLinearLayoutManager;
     private CommentAndPostRecyclerViewAdapter mAdapter;
     private RecyclerView.SmoothScroller mSmoothScroller;
@@ -255,6 +256,61 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
 
         mLinearLayoutManager = new LinearLayoutManager(this);
         mRecyclerView.setLayoutManager(mLinearLayoutManager);
+
+        if (children != null && children.size() > 0) {
+            mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+                @Override
+                public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
+                    super.onScrolled(recyclerView, dx, dy);
+                    if (!mIsSmoothScrolling) {
+                        if (dy > 0) {
+                            fab.hide();
+                        } else {
+                            fab.show();
+                        }
+                    }
+
+                    if (!isLoadingMoreChildren && loadMoreChildrenSuccess) {
+                        int visibleItemCount = mLinearLayoutManager.getChildCount();
+                        int totalItemCount = mLinearLayoutManager.getItemCount();
+                        int firstVisibleItemPosition = mLinearLayoutManager.findFirstVisibleItemPosition();
+
+                        if ((visibleItemCount + firstVisibleItemPosition >= totalItemCount) && firstVisibleItemPosition >= 0) {
+                            fetchMoreComments();
+                        }
+                    }
+                }
+
+                @Override
+                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                    if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+                        mIsSmoothScrolling = false;
+                    }
+                }
+            });
+        } else {
+            mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+                @Override
+                public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
+                    super.onScrolled(recyclerView, dx, dy);
+                    if (!mIsSmoothScrolling) {
+                        if (dy > 0) {
+                            fab.hide();
+                        } else {
+                            fab.show();
+                        }
+                    }
+                }
+
+                @Override
+                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                    if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+                        mIsSmoothScrolling = false;
+                    }
+                }
+            });
+        }
+
         mSmoothScroller = new LinearSmoothScroller(this) {
             @Override
             protected int getVerticalSnapPreference() {
@@ -563,10 +619,18 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                                             mAdapter.addComments(expandedComments, hasMoreChildren);
 
                                             if (children.size() > 0) {
+                                                mRecyclerView.clearOnScrollListeners();
                                                 mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                                                     @Override
                                                     public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                                                         super.onScrolled(recyclerView, dx, dy);
+                                                        if (!mIsSmoothScrolling) {
+                                                            if (dy > 0) {
+                                                                fab.hide();
+                                                            } else {
+                                                                fab.show();
+                                                            }
+                                                        }
 
                                                         if (!isLoadingMoreChildren && loadMoreChildrenSuccess) {
                                                             int visibleItemCount = mLinearLayoutManager.getChildCount();
@@ -578,6 +642,13 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                                                             }
                                                         }
                                                     }
+
+                                                    @Override
+                                                    public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                                                        if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+                                                            mIsSmoothScrolling = false;
+                                                        }
+                                                    }
                                                 });
                                             }
                                         }
@@ -636,10 +707,18 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                         mAdapter.addComments(expandedComments, hasMoreChildren);
 
                         if (children.size() > 0) {
+                            mRecyclerView.clearOnScrollListeners();
                             mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                                 @Override
                                 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                                     super.onScrolled(recyclerView, dx, dy);
+                                    if (!mIsSmoothScrolling) {
+                                        if (dy > 0) {
+                                            fab.hide();
+                                        } else {
+                                            fab.show();
+                                        }
+                                    }
 
                                     if (!isLoadingMoreChildren && loadMoreChildrenSuccess) {
                                         int visibleItemCount = mLinearLayoutManager.getChildCount();
@@ -651,6 +730,13 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                                         }
                                     }
                                 }
+
+                                @Override
+                                public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
+                                    if (newState == RecyclerView.SCROLL_STATE_IDLE) {
+                                        mIsSmoothScrolling = false;
+                                    }
+                                }
                             });
                         }
                         if (changeRefreshState) {
@@ -991,6 +1077,7 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                 }
                 mSmoothScroller.setTargetPosition(nextParentPosition);
                 if (mLinearLayoutManager != null) {
+                    mIsSmoothScrolling = true;
                     mLinearLayoutManager.startSmoothScroll(mSmoothScroller);
                 }
             }
@@ -1007,6 +1094,7 @@ public class ViewPostDetailActivity extends BaseActivity implements FlairBottomS
                 }
                 mSmoothScroller.setTargetPosition(nextParentPosition);
                 if (mLinearLayoutManager != null) {
+                    mIsSmoothScrolling = true;
                     mLinearLayoutManager.startSmoothScroll(mSmoothScroller);
                 }
             }