我在从FragmentActivity进行向前和向后导航时收到异常，其中包含ListView以及从自定义Loader加载的数据（它是从本地sqlite数据库加载的），并且不知道如何处理...
这是一个堆栈跟踪：
Uncaught exception: Unable to destroy activity {com.snyer.bestprice/com.snyer.bestprice.PriceTracerActivity}: java.lang.RuntimeException: Unable to destroy activity {com.snyer.bestprice/com.snyer.bestprice.CartFragmentActivity}: java.util.ConcurrentModificationException
java.lang.RuntimeException: Unable to destroy activity {com.snyer.bestprice/com.snyer.bestprice.PriceTracerActivity}: java.lang.RuntimeException: Unable to destroy activity {com.snyer.bestprice/com.snyer.bestprice.CartFragmentActivity}: java.util.ConcurrentModificationException
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3106)
at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3171)
at android.app.ActivityThread.access$2100(ActivityThread.java:132)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1071)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:150)
at android.app.ActivityThread.main(ActivityThread.java:4293)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.RuntimeException: Unable to destroy activity {com.snyer.bestprice/com.snyer.bestprice.CartFragmentActivity}: java.util.ConcurrentModificationException
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3106)
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:2994)
at android.app.LocalActivityManager.dispatchDestroy(LocalActivityManager.java:625)
at android.app.ActivityGroup.onDestroy(ActivityGroup.java:85)
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3088)
... 11 more
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$ArrayListIterator.next(ArrayList.java:576)
at android.database.DataSetObservable.notifyInvalidated(DataSetObservable.java:42)
at android.widget.BaseAdapter.notifyDataSetInvalidated(BaseAdapter.java:54)
at android.support.v4.widget.CursorAdapter.swapCursor(CursorAdapter.java:352)
at com.snyer.bestprice.CartFragmentActivity.onLoaderReset(CartFragmentActivity.java:412)
at android.support.v4.app.LoaderManagerImpl$LoaderInfo.destroy(LoaderManager.java:337)
at android.support.v4.app.LoaderManagerImpl.doDestroy(LoaderManager.java:773)
at android.support.v4.app.FragmentActivity.onDestroy(FragmentActivity.java:318)
at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3088)
... 15 more
此代码段（CartFragmentActivity.java:412）的行
mCartCursorAdapter.swapCursor(null);处发生异常：public void onLoaderReset(Loader<Cursor> loader) {
switch (loader.getId()) {
case LOADER_CART_LIST_ID:
mCartListCursorAdapter.swapCursor(null);
break;
case LOADER_CART_CONTENTS_ID:
mCartCursorAdapter.swapCursor(null);
break;
}
}
在这里可以采取什么措施来消除此异常？
最佳答案
sdk源提供了一个很好的提示作为注释：
在Android 4.0.4中，它是：
public void notifyInvalidated() {
synchronized(mObservers) {
for (int i = mObservers.size() - 1; i >= 0; i--) {
mObservers.get(i).onInvalidated();
}
}
}
在早期版本中，它是：
synchronized (mObservers) {
for (DataSetObserver observer : mObservers) {
observer.onInvalidated();
}
}
关于onChange方法中的相同更改，4.0.4源具有以下注释：
// since onChanged() is implemented by the app, it could do anything, including
// removing itself from {@link mObservers} - and that could cause problems if
// an iterator is used on the ArrayList {@link mObservers}.
// to avoid such problems, just march thru the list in the reverse order.
我不知道以任何非法方式操纵观察者的ArrayList。由于这是在以后的API中解决的，并且我认为对我的应用程序没有任何影响，我想我将只是忽略带有日志条目或类似内容的异常。
关于java - 做swapCursor()时如何处理ConcurrentModificationException？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/12777308/