NPE when calling findLastCompletelyVisibleItemPosition

[frazer-rbsn]

 Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.ViewGroup$LayoutParams android.view.View.getLayoutParams()' on a null object reference
   at com.tonicartos.superslim.SectionData.(SectionData.java:36)
   at com.myapp.app.misc.RecyclerView.com.tonicartos.superslim.LayoutManager.findLastCompletelyVisibleItemPosition(RecyclerView.java:1212)
   at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3665)
   at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2824)
   at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3011)
   at android.view.View.layout(View.java:15614)
   at android.view.ViewGroup.layout(ViewGroup.java:4968)

This only happens when we redraw the layout after a screen rotation. It doesn't happen every time and doesn't happen for every user, which makes me think it could be a race condition. But a colleague with a slow device can reproduce it almost every time.

Here's how we are calling the code:

@Override
public void onScrolled(int dx, int dy) {
    super.onScrolled(dx, dy);
    if(transcriptMode == TRANSCRIPT_MODE_NORMAL) {
        com.tonicartos.superslim.LayoutManager layoutManager = ((com.tonicartos.superslim.LayoutManager) getLayoutManager());
        if (layoutManager.getItemCount() == 0) return;

        forceTranscriptScroll = layoutManager.findLastCompletelyVisibleItemPosition() == layoutManager.getItemCount() - 1;
    }
}

We are using version 0.4.13 and it has been seen on Android 4 and 5.

[gatorboy]

Happens for me too. @TonicArtos Any plan on fixing this?

[sofiahellofresh]

We also have this issue. @frazer-rbsn @gatorboy have you found a work around for it?

[gatorboy]

@sofiahellofresh I was able to write some workaround for this..

                final View view = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
                int lastVisiblePosition;
                if (view == null) {
                    lastVisiblePosition = 0;
                } else {
                    lastVisiblePosition = layoutManager.findLastCompletelyVisibleItemPosition();
                    if (lastVisiblePosition == LayoutManager.INVALID_POSITON) {
                        lastVisiblePosition = 0;
                    }
                }