android - AdWhirl 在关闭网络后导致 java.lang.NullPointerException

Question

我在我的一个应用程序中使用 AdWhirl 和 Admob，发布后，我们从 adwhirl 中得到了很多错误，并且它很容易像这样重现:

广告出现后，我关闭wifi，等待广告超时，然后按返回按钮退出应用程序。

然后出现bug。src可以从this下载. 异常(exception)是这样的:

 05-17 11:00:13.265: E/AndroidRuntime(12482): java.lang.RuntimeException: Unable to destroy activity {me.test.admob/me.test.admob.AdWhirlTestActivity}: java.lang.NullPointerException
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3112)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3130)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread.access$1200(ActivityThread.java:123)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1180)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.os.Looper.loop(Looper.java:137)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread.main(ActivityThread.java:4424)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at java.lang.reflect.Method.invokeNative(Native Method)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at java.lang.reflect.Method.invoke(Method.java:511)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at dalvik.system.NativeStart.main(Native Method)
05-17 11:00:13.265: E/AndroidRuntime(12482): Caused by: java.lang.NullPointerException
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.webkit.WebView.requestFocus(WebView.java:7650)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2110)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2154)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.requestFocus(ViewGroup.java:2113)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.View.requestFocus(View.java:5323)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewRootImpl.clearChildFocus(ViewRootImpl.java:2200)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.clearChildFocus(ViewGroup.java:669)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.clearChildFocus(ViewGroup.java:669)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.clearChildFocus(ViewGroup.java:669)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.clearChildFocus(ViewGroup.java:669)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.clearChildFocus(ViewGroup.java:669)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.removeViewInternal(ViewGroup.java:3591)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.removeViewInternal(ViewGroup.java:3561)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.view.ViewGroup.removeView(ViewGroup.java:3509)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:998)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.support.v4.app.FragmentManagerImpl.dispatchDestroy(FragmentManager.java:1843)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.support.v4.app.FragmentActivity.onDestroy(FragmentActivity.java:314)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.Activity.performDestroy(Activity.java:4629)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1079)
05-17 11:00:13.265: E/AndroidRuntime(12482):    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3099)
05-17 11:00:13.265: E/AndroidRuntime(12482):    ... 11 more

经过我的测试，我发现只有在 ViewPager 中使用带有 ListFragment 的 adwhirl 时才会出现此异常。如果我只在 ListFragment 中使用或在 ViewPager 中使用 Fragment，它可以正常工作。 但是我还是想知道是哪里出了问题，如何解决这个异常。

任何答案将不胜感激。

Answer 1

1. 确保在 onDestory() 方法中处理 AdWhirl
2. 使用 try catch 来捕获 NullPointer，联系开发人员并希望他们修复此问题(如果是错误)