Android Crash SDK on android.widget.PopupWindow $ 1.onScrollChanged (PopupWindow.java:132)

Question

Can someone with the google dev team explain how to avoid this crash on pre-ics devices? In my case, the ImageButton in the ListView element is a PopupWindow anchor to create a dropdown list. I tried all popup.dismiss (), popup = null, etc., but nothing prevents this from being a problem when the adapter is reset.

I get the following exception:

FATAL EXCEPTION: main java.lang.NullPointerException at android.widget.PopupWindow$1.onScrollChanged(PopupWindow.java:132) 05-21 17:02:27.736: E/AndroidRuntime(25836): at android.view.ViewTreeObserver.dispatchOnScrollChanged(ViewTreeObserver.java:607) 

This popup file is in a list item. After removing the last list item from the ListView, I resetAdapter to set the footer. Then, when I move away from the screen, this error occurs.

Not in an Ice Cream Sandwich: An Ice Cream Sandwich. See https://android.googlesource.com/platform/frameworks/base/+/749b0eb2c9a52bb188fd8900859b3725889e0ec0%5E!/

This indicates a fix related to the null anchor PopupWindow. What can be done? In my case, the button in the ListView element is the anchor of the popup. and the same problem here:

https://github.com/JakeWharton/ActionBarSherlock/issues/487

Answer 1

Not sure if the OP still needs it, since six months later I just saw it.

This is fixed in ICS. However, you can assign a fixed scroll listener through reflection!

 if(Build.VERSION.SDK_INT<Build.VERSION_CODES.ICE_CREAM_SANDWICH){ try { final Field fAnchor = PopupWindow.class.getDeclaredField("mAnchor"); fAnchor.setAccessible(true); Field listener = PopupWindow.class.getDeclaredField("mOnScrollChangedListener"); listener.setAccessible(true); final ViewTreeObserver.OnScrollChangedListener originalListener = (ViewTreeObserver.OnScrollChangedListener) listener.get(window); ViewTreeObserver.OnScrollChangedListener newListener= new ViewTreeObserver.OnScrollChangedListener() { public void onScrollChanged() { try { // PopupWindow implementation has WeakReference<View> WeakReference<View> mAnchor = (WeakReference<View>) fAnchor.get(window); if (mAnchor == null || mAnchor.get() == null) { return; } else { originalListener.onScrollChanged(); } } catch (Exception e) { e.printStackTrace(); } } }; listener.set(window,newListener); } catch (Exception e) { e.printStackTrace(); } }