android - IllegalStateException - 使用 AutocompleteTextView 支持 LoaderManager

Question

我想到使用 CursorLoaders 和 Loadermanagers 的好处之一是您不需要手动管理游标的生命周期。因此，我使用 loadermanager 将适配器绑定(bind)到使用支持包的 AutoCompleteTextView。

除了它随机抛出一个错误“IllegalStateException - 试图重新打开一个已经关闭的对象”之外，它工作得很好。如果我们使用加载程序管理器，那肯定不会发生吗？

代码如下:

package com.bhagwad.tennis;

import android.appwidget.AppWidgetManager;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.support.v4.widget.SimpleCursorAdapter.CursorToStringConverter;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AutoCompleteTextView;
import android.widget.Button;

import com.bhagwad.tennis.TennisSchedule.TennisScheduleColumns;


public class WidgetConfiguration extends FragmentActivity implements OnClickListener, LoaderCallbacks<Cursor> {

    Button mSaveWidget;
    AutoCompleteTextView mPlayerName;
    int mAppWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
    String mSelection ="";
    SimpleCursorAdapter mAdapter;

    public static String PREFS = "com.bhagwad.tennis.appwidget";
    public static final String PREFS_PREFIX_KEY = "prefix_";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.widget_configuration);

        mPlayerName = (AutoCompleteTextView) findViewById(R.id.edit_filter);

        mPlayerName.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

                if (!s.equals(""))
                    mSelection = s.toString();
                else
                    mSelection = "";

                getSupportLoaderManager().restartLoader(0, null, WidgetConfiguration.this);



            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {
                // TODO Auto-generated method stub

            }

            @Override
            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub

            }
        });

        // Set up the adapter

        mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, null, new String[] {TennisScheduleColumns.PLAYER_NAME}, new int[] {android.R.id.text1}, 0);
        mAdapter.setCursorToStringConverter(new CursorToStringConverter() {

            @Override
            public CharSequence convertToString(Cursor c) {

                return c.getString(c.getColumnIndexOrThrow(TennisScheduleColumns.PLAYER_NAME)); 

            }
        });

        mPlayerName.setAdapter(mAdapter);

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

    }


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

        return new CursorLoader(this, TennisScheduleColumns.CONTENT_URI_PLAYERS, new String[] {TennisScheduleColumns._ID, TennisScheduleColumns.PLAYER_NAME}, TennisScheduleColumns.PLAYER_NAME + " LIKE ?", new String[] {"%"+mSelection+"%"}, null);

    }


    @Override
    public void onLoaderReset(Loader<Cursor> arg0) {
        mAdapter.swapCursor(null);

    }

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


    }


}

这是错误堆栈:

08-16 22:21:23.244: E/AndroidRuntime(25475): java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT _id, player_name FROM players WHERE (player_name LIKE ?)) 
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:33)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:82)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:164)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.sqlite.SQLiteCursor.onMove(SQLiteCursor.java:147)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.AbstractCursor.moveToPosition(AbstractCursor.java:178)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.database.CursorWrapper.moveToPosition(CursorWrapper.java:162)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.support.v4.widget.CursorAdapter.getItem(CursorAdapter.java:213)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.widget.AutoCompleteTextView.buildImeCompletions(AutoCompleteTextView.java:1113)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.widget.AutoCompleteTextView.showDropDown(AutoCompleteTextView.java:1072)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.widget.AutoCompleteTextView.updateDropDownForFilter(AutoCompleteTextView.java:950)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.widget.AutoCompleteTextView.onFilterComplete(AutoCompleteTextView.java:932)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.widget.Filter$ResultsHandler.handleMessage(Filter.java:285)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.os.Looper.loop(Looper.java:137)
08-16 22:21:23.244: E/AndroidRuntime(25475):    at android.app.ActivityThread.main(ActivityThread.java:4507)

有什么可能出错的想法吗？

Answer 1

OnLoadFinished 似乎有时会在游标失效时被调用 - 如果您对游标进行 isClosed() 测试并通过，您会发现它在一次(大量)尝试中关闭。

不幸的是，放置在 OnLoadFinished 中的“标准”代码会立即在适配器上执行 changeCursor()，接下来是困惑、堆栈转储、瘟疫等。

我的解决方案并不比您的 try/catch 更漂亮。忽略伪造的 OnLoadFinished 并冒着最终用户获得空白 UI 的风险。