CoordinatorLayout + SwipeRefreshLayout + Endless RecyclerView的怪异行为

Question

I'm trying to implement a CoordinatorLayout with a ToolBar that collapses. I already have a SwipeRefreshLayout with a RecyclerView inside. This recycler view also has an onScrollListener to load more content and a custom adapter to show a loading ViewHolder when it's loading more content.

Everything was working fine before I tried adding the CoordinatorLayout . Now I have two problems:

1. When loading items for the first time, the loading ViewHolder shows up and it's well placed (below the ToolBar ). When it finishes, the loading is removed and the items are added. The problem is that the first item is hidden. It's like the second item is actually the first one. It's completely impossible to see the first item even when it is bigger than the ToolBar . But when I use swipe to refresh, the item gets placed properly. I have no idea why this happens.

2. When I'm using swipe to refresh, it loads items two times. The first time is the normal load and the second is a load for more items because of the onScrollListener . However the scroll is still on the top of the list. The recycler view items stay invisible until I scroll (I think this is because I only notify the adapter of the new items but we are still at the top of the list).

However, I don't know what to change in the listener to fix this.

Here's the listener:

    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            if(!adapter.isLoading()) {
                LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
                //position starts at 0
                if (layoutManager.findLastCompletelyVisibleItemPosition() >= layoutManager.getItemCount() - 2) {
                    loadSubmissions(false);
                }
            }
        }
    });

My activity layout:

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/coordinatorLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBarLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <include
            android:id="@+id/toolbar"
            layout="@layout/toolbar" />

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/contentView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            android:paddingBottom="6dp"
            android:paddingTop="6dp"
            android:scrollbars="vertical"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    </android.support.v4.widget.SwipeRefreshLayout>

</android.support.design.widget.CoordinatorLayout>

My toolbar:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimary"
    android:elevation="4dp"
    app:layout_scrollFlags="scroll|enterAlways">
</android.support.v7.widget.Toolbar>

Answer 1

Both problems are fixed. For the first one, when I was removing the loading ViewHolder I was actually doing notifyItemInserted instead of notifyItemRemoved .

For the second problem it's because I'm calling notifyDatasetChanged when I'm using swipe to refresh.

@Override public void onRefresh() {
    adapter.clear();
    adapter.notifyDataSetChanged();
    loadSubmissions(true);
}

When I clear the adapter with the swipe to refresh, I'm swiping so it means that the onScrollListener will be called.

I changed the listener and added a verification to don't load more if there are no items.

mRecyclerView.addOnScrollListener(new EndlessRecyclerOnScrollListener(linearLayoutManager) {
    @Override
    public void onLoadMore(int current_page) {
        // Doesnt load multiples times with the same scroll and doesnt load if there are no items
        if(!adapter.isLoading() && adapter.getItemCount() > 0) {
            loadSubmissions(false);
        }
    }
});