在我们的项目中，我们与Lists进行了大量交易，并在过去使用了以下“模式”：
ListView在Fragment中，在onActivityCreated中初始化，我们首先启动CursorLoaders，然后在onFinish swapCusor中启动ListAdapter。然后，我们使用filterQueryProvider实现了一个搜索功能，它只返回一个带有contentResolver.query（...）的游标。如果我在选择列表中的某些内容时进行了一些方向更改，则在许多情况下会出现以下错误（不定期）：
android.database.StaleDataException: Attempted to access a cursor after it has been closed.
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3378)
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread.access$700(ActivityThread.java:127)
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1162)
12-05 10:36:59.531: E/ACRA(12079): at android.os.Handler.dispatchMessage(Handler.java:99)
12-05 10:36:59.531: E/ACRA(12079): at android.os.Looper.loop(Looper.java:137)
12-05 10:36:59.531: E/ACRA(12079): at android.app.ActivityThread.main(ActivityThread.java:4448)
12-05 10:36:59.531: E/ACRA(12079): at java.lang.reflect.Method.invokeNative(Native Method)
12-05 10:36:59.531: E/ACRA(12079): at java.lang.reflect.Method.invoke(Method.java:511)
12-05 10:36:59.531: E/ACRA(12079): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
12-05 10:36:59.531: E/ACRA(12079): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
12-05 10:36:59.531: E/ACRA(12079): at dalvik.system.NativeStart.main(Native Method)
12-05 10:36:59.531: E/ACRA(12079): Caused by: android.database.StaleDataException: Attempted to access a cursor after it has been closed.
12-05 10:36:59.531: E/ACRA(12079): at android.database.BulkCursorToCursorAdaptor.throwIfCursorIsClosed(BulkCursorToCursorAdaptor.java:75)
12-05 10:36:59.531: E/ACRA(12079): at android.database.BulkCursorToCursorAdaptor.getColumnNames(BulkCursorToCursorAdaptor.java:170)
12-05 10:36:59.531: E/ACRA(12079): at android.database.AbstractCursor.getColumnIndex(AbstractCursor.java:248)
12-05 10:36:59.531: E/ACRA(12079): at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:266)
12-05 10:36:59.531: E/ACRA(12079): at android.database.CursorWrapper.getColumnIndexOrThrow(CursorWrapper.java:78)
12-05 10:36:59.531: E/ACRA(12079): at android.support.v4.widget.CursorAdapter.swapCursor(CursorAdapter.java:344)
12-05 10:36:59.531: E/ACRA(12079): at
在方向更改后在onLoadFinished中使用swapCursor时就是这种情况。
我现在使用带有参数的restartLoader重新实现过滤器功能，并使用带有附加路径的Contacts.CONTENT_FILTER_URI作为约束，然后将此光标交换到onLoadFinished，所以我删除了filterQueryProvider，它看起来工作正常。
问题是：是否有可能（或良好实践）最初使用CursorLoader和filterQueryProvider？还是我必须决定？因为我在使用filterQueryProvider时得到了相同的结果，只是使用约束null进行过滤，这只是加载我所需的联系人列表并在之后进行过滤。
有什么建议吗？我没有通过谷歌找到这方面的mathinc信息;）
这是我当前的LoaderCallbacks实现btw：
private LoaderManager.LoaderCallbacks<Cursor> phoneBookContactsLoaderCallback = new LoaderManager.LoaderCallbacks<Cursor>() {
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
// if(constraint != null && constraint.length() > 0) {
// selection = Contacts.DISPLAY_NAME + " LIKE ?";
// selectionArgs = new String [] {"%" + constraint + "%"};
// }
numLoaderManagersRunning++;
String constraint = null;
if(args != null){
constraint = args.getString(CONSTRAINT);
}
Uri uri = null;
if(constraint!= null && !constraint.isEmpty()){
uri = Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI, constraint);
} else {
uri = Contacts.CONTENT_URI;
}
return new CursorLoader(getActivity(), uri , PROJECTION_PHONEBOOK_CONTACTS,
null, null, Contacts.DISPLAY_NAME + " COLLATE NOCASE ASC");
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
Logger.e(TAG, "Load finished ");
// phoneBookContactsCursorAdapter.swapCursor(new MatrixCursor(new String [] { Contacts._ID,
// Contacts.DISPLAY_NAME, Contacts.PHOTO_ID }));
phoneBookContactsCursorAdapter.swapCursor(data);
if (actualMultiFilterListener != null){
actualMultiFilterListener.onFilterComplete(data.getCount());
}
//filterList("");
numLoaderManagersRunning--;
if (numLoaderManagersRunning <= 0) {
// The list should now be shown.
if (isResumed()) {
setListShown(true);
} else {
setListShownNoAnimation(true);
}
}
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
// phoneBookContactsCursorAdapter.swapCursor(null);
Logger.e(TAG, "Load resetted ");
}
};
答案 0 :(得分：4)
使用FilterQueryProvider时使用restartLoader而不是initLoader
答案 1 :(得分：3)
有点晚了但是我遇到了完全相同的问题而且评论并没有很好地解释。对于那些面临问题的人来说，解决方案是：
＆＃34;停止使用FilterQueryProvider。 CursorLoader也是一个替代品：用你的过滤器重启它你就没事了。＆＃34; （source）
这意味着什么;
而不是这样做：
@Override
public Cursor runQuery(CharSequence listId) {
return mDb.getContacts(listId);
}// DO NOT set direct database query, has no observation at all.
或
@Override
public Cursor runQuery(CharSequence listId) {
return getContentManager.query(....,new String[]{listId}...
}// DO NOT return content manager result, forgets observers.
或
@Override
public Cursor runQuery(CharSequence listId) {
Bundle bundle = new Bundle();
bundle.putCharSequence("selected", listId);
getLoaderManager().restartLoader(CURSOR_LOADER_CONTACTS, bundle, MainActivity.this);
return null;
}// DO NOT restart the cursor loader with new info, screws observers.
结合使用mContactAdapter.getFilter().filter(id+""); （同时应用过滤器）
这样做：
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
switch (id) {
case CURSOR_LOADER_CONTACTS:
long mListId = 0;
if (args != null) {
mListId = args.getLong(CONTACT_FILTER);
}
return new CursorLoader(this, ContentProvider.CONTACT_DISPLAY_URI, null, ContactTable.COLUMN_GROUP_ID+"=?", new String[]{id+""}, null);
} //Apply filter here with new info comes from 'restartLoader'
return null;
}
与getLoaderManager().restartLoader(MainActivity.CURSOR_LOADER_CONTACTS, bundle, MainActivity.this);
假设MainActivity.this实施LoaderManager.LoaderCallbacks<Cursor>