The observer is null.最终解决方案

在使用BaseAdapter的问题

java.lang.IllegalArgumentException: The observer is null. at android.database.Observable.unregisterObserver(Observable.java:64) at android.widget.BaseAdapter.unregisterDataSetObserver(BaseAdapter.java:42) at android.widget.AbsListView.onDetachedFromWindow(AbsListView.java:2872) at android.view.View.dispatchDetachedFromWindow(View.java:11908) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2647) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2645) at android.view.ViewRootImpl.dispatchDetachedFromWindow(ViewRootImpl.java:2685) at android.view.ViewRootImpl.doDie(ViewRootImpl.java:4044) at android.view.ViewRootImpl.die(ViewRootImpl.java:4027) at android.view.WindowManagerImpl.removeViewImmediate(WindowManagerImpl.java:375) at android.view.WindowManagerImpl$CompatModeWrapper.removeViewImmediate(WindowManagerImpl.java:170) at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3352) at android.app.ActivityThread.access$1200(ActivityThread.java:140) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1266) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4914) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:808) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:575) at dalvik.system.NativeStart.main(Native Method)

解决方法

继承BaseAdapter的时候写入 @Override public void unregisterDataSetObserver(DataSetObserver observer) { if (observer != null) {        super.unregisterDataSetObserver(observer);    } }