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我在关闭应用程序或让手机在应用程序打开的情况下进入睡眠状态后收到此错误消息。

当我让手机休眠时，我会收到 30 到 61 条此错误消息的日志条目。在加载 ListFragment 之前记录错误。我怀疑片段已加载，但在片段的信息条目之前记录了错误。

当我关闭应用程序时，我只得到 1 个错误条目，该条目是在 onLoaderReset() 调用之后记录的。我在应用程序关闭之前关闭了数据库，这似乎有帮助。

该应用程序有效，但我担心它一旦在各种手机上运行就会失败。

除了 onLoaderReset() 中的 adapter.swapCursor(null) 之外，我没有显式控制光标。

我很欣赏有关如何解决此错误的任何想法。

谢谢

public class ChildList extends ListFragment implements
    LoaderManager.LoaderCallbacks<Cursor>, DatabaseConstants, GoodiList {

private final String TAG = "ChildList";

// database columns that we will retreive
final String[] PROJECTION = new String[] { CHILD_ID_COLUMN,
        CHILD_NAME_COLUMN };

// selects all
final String SELECTION = null;

SimpleCursorAdapter adapter = null;

private ListParent parentActivity;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Log.e(TAG, "on Create");
    String[] fromColumns = { CHILD_NAME_COLUMN, CHILD_ID_COLUMN };

    int[] toViews = { R.id.name_column, R.id.id_column };

    adapter=new SimpleCursorAdapter(
            getActivity(),
            R.layout.child_list_entry,
            null,
            fromColumns,
            toViews,
            0
            );

    setListAdapter(adapter);

    getLoaderManager().initLoader(0, null, this);

    Log.i(TAG, "finished on Create");
}


public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    LongClickListener longClickListener = new LongClickListener();

    getListView().setOnItemLongClickListener(longClickListener);
}

@Override
public void setListAdapter(ListAdapter adapter) {
    super.setListAdapter(adapter);
}

@Override
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {

    Log.v(TAG, "starting on create loader");

    Uri CHILD_URI = ChildContentProvider.CONTENT_URI;

    CursorLoader cursorLoader = new CursorLoader(getActivity(), CHILD_URI,
            PROJECTION, SELECTION, null, null);

    Log.v(TAG, "finished on create loader");

    return cursorLoader;
}

@Override
public void onLoadFinished(Loader<Cursor> arg0, Cursor newCursor) {
    adapter.swapCursor(newCursor);

    if (newCursor != null) {
        int rowCount = newCursor.getCount();

        Log.v(TAG, "--- onLoadFinished:  got " + rowCount + " children");
    }
}

/**
 * this used to delete. However, we need it to select usually. Now delete is
 * done by long click.
 */
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);

    // delete child - remove child from list and database
    Object item = l.getItemAtPosition(position);

    Cursor cursor = (Cursor) item;

    int nameCol = cursor.getColumnIndex(CHILD_NAME_COLUMN);
    int idCol = cursor.getColumnIndex(CHILD_ID_COLUMN);

    final String name = cursor.getString(nameCol);

    final int childId = cursor.getInt(idCol);

    Log.i(TAG, "selected " + name + " id: " + childId + " at position "
            + position);

    cursor.close();

    parentActivity.listItemSelected(this, position, childId);

}

/**
 * Forces cursor to requery database and list to be update. Used when a new
 * child is entered in parent activity's EditText field.
 */
public void notifyDataChanged() {

    Log.i(TAG, "told adapter that data changed");

    getLoaderManager().restartLoader(0, null, this);

    adapter.notifyDataSetChanged();
}

/** tell adapter that cursor is no longer valid*/
@Override
public void onLoaderReset(Loader<Cursor> arg0) {
Log.i(TAG,"---- onLoaderReset -----");

adapter.swapCursor(null);

}

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);

    parentActivity = (ListParent) activity;

    parentActivity.setList(this);

}
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2 回答 2

0

你应该使用changeCursor(Cursor cursor)而不是swapCursor(Cursor cursor)

如果您查看文档，您会看到它也会关闭旧光标。

于 2017-10-26T20:56:42.080 回答
0

我有同样的问题，我通过仔细查看文档解决了它。

根据文档，http://developer.android.com/reference/android/widget/CursorAdapter.html#swapCursor(android.database.Cursor)

该方法swapCursor(Cursor data)返回原始未关闭的游标。如果新游标与旧游标相同或不存在旧游标，则返回 null。

通过更改我的代码

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    adapter.swapCursor(data);
}

至

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    Cursor cursor = adapter.swapCursor(data);
    if (cursor != null) {
        cursor.close();
    }
}

我阻止了这些警告的出现。

注意：您也应该对onLoaderReset()方法执行相同的操作。因为即使你这样做adapter.swapCursor(null)，它也会返回旧光标。

于 2015-10-15T01:52:49.163 回答