PopupWindow错误:PopupWindow$1.onScrollChanged 出现 NullPointerException和PopupViewContainer.dispatchKeyEvent 出现 NullPointerException
错误1：
java.lang.NullPointerException at android.widget.PopupWindow$1.onScrollChanged(PopupWindow.java:127) at android.view.ViewTreeObserver.dispatchOnScrollChanged(ViewTreeObserver.java:607) at android.view.ViewRoot.draw(ViewRoot.java:1453) at android.view.ViewRoot.performTraversals(ViewRoot.java:1335) at android.view.ViewRoot.handleMessage(ViewRoot.java:1991) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:150) at android.app.ActivityThread.main(ActivityThread.java:4385) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:507) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607) at dalvik.system.NativeStart.main(Native Method)
这个错误经常出现在Gingerbread或更早的版本，3.0以下。是系统的bug
解决方案：
new PopupWindow之后加上如下的方法进行检查即可，为了兼容3.0以下版本，这个操作还是必要的
private void fixPopupWindow(final PopupWindow window) { 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() { @Override public void onScrollChanged() { try { WeakReference<View> mAnchor = (WeakReference<View>) fAnchor.get(window); if (mAnchor == null || mAnchor.get() == null) { return; } else { originalListener.onScrollChanged(); } } catch (IllegalAccessException e) { e.printStackTrace(); } } }; listener.set(window, newListener); } catch (Exception e) { e.printStackTrace(); } } }
参考：
https://github.com/JakeWharton/ActionBarSherlock/issues/752
https://groups.google.com/forum/?fromgroups=#!msg/osmeditor4android/RsHYoY6XqlU/-WGSKWm5OMAJ
错误2：
java.lang.NullPointerException at android.widget.PopupWindow$PopupViewContainer.dispatchKeyEvent(PopupWindow.java:1426) at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2627) at android.view.ViewRoot.deliverKeyEvent(ViewRoot.java:2592) at android.view.ViewRoot.handleMessage(ViewRoot.java:1881) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:130) at android.app.ActivityThread.main(ActivityThread.java:3687) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:507) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) at dalvik.system.NativeStart.main(Native Method)
解决方法：创建PopupWindow 的时候不调用 setFocusable(true)，在showAtLocation后在调用setFocusable(true);并且在 dismiss的时候 调用setFocusable(false)
参考：
http://stackoverflow.com/questions/7768728/popupwindow-crash-on-dispatch-event
转载于:https://www.cnblogs.com/xinye/p/3642678.html
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