在Android中使用SimpleCursorAdapter时出现异常和崩溃

Question

Android 新手在使用 SimpleCursorAdapter 时遇到了一些无法解决的问题。

这是代码（省略导入）：

package se.ribit.bb;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class CountyBrowser extends Activity {
  private AVApplication audiovideo;
  private final String LOG_TAG = AVApplication.LOG_TAG;
  private final String TAG = "=== " + CountyBrowser.class.getSimpleName() + ": ";

  static final String[] FROM = { LocationDB.C_NAME};
  static final int[]    TO   = { R.id.locationName };

  //  DB dbHelper;
  private Cursor cursor;
  private ListView listItems;
  private SimpleCursorAdapter adapter;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.d(LOG_TAG, TAG + "onCreate");

    setContentView(R.layout.county_main_view);

    // View for the adapter 
    listItems = (ListView) findViewById(R.id.county_listview);

    // Get the application context
    audiovideo = (AVApplication) getApplication();

    audiovideo.httpCommand(Commands.GET_COUNTIES, null);
  }

  @Override
  protected void onResume() {
    super.onResume();

    showCounties();
  }

  public void showCounties() {
    Log.d(LOG_TAG, TAG + "refreshItemsList();");

    // Get a cursor with all item updates
    cursor = audiovideo.getLocationDB().getCounties();
    startManagingCursor(cursor);

    // Setup the adapter
    adapter = new SimpleCursorAdapter(this, R.layout.county_listview_item, cursor, FROM, TO);

    listItems.setAdapter(adapter);
    listItems.setOnItemClickListener(new OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        int countyID = cursor.getInt(cursor.getColumnIndex(LocationDB.C_ID));
        String countyName = cursor.getString(cursor.getColumnIndex(LocationDB.C_NAME));
        String foo = String.format(TAG + "Clicked ID #%d (%s)", countyID, countyName);
        Log.i(LOG_TAG, foo);

        // Show the item in a new activity
        Intent apan = new Intent(audiovideo, MunicipalBrowser.class);
        apan.putExtra("countyID", countyID);
        startActivity(apan);
      }
    });
  } // refreshItemsList
}

即：这将打开一个列表视图，并用我所在地区周围的一堆县名填充它。单击一个县时，会启动另一个活动（具有几乎相同的代码），显示该县的市政当局。

该代码大部分都有效。 LogView 中时不时会弹出这些行（每个列表视图单元格一组）：

10-11 09:28:06.601: INFO/dalvikvm(244): Uncaught exception thrown by finalizer (will be discarded):
10-11 09:28:06.641: INFO/dalvikvm(244): Ljava/lang/IllegalStateException;: Finalizing cursor android.database.sqlite.SQLiteCursor@44c7e808 on null that has not been deactivated \

或关闭 10-11 09:28:06.651：信息/dalvikvm(244)：在 android.database.sqlite.SQLiteCursor.finalize(SQLiteCursor.java:596) 10-11 09:28:06.651: INFO/dalvikvm(244): at dalvik.system.NativeStart.run(Native Method)

我不明白为什么我得到这些，但由于模拟器没有崩溃，所以我没有太麻烦了。

现在出现严重错误：当我的列表视图启动并且我在一段时间内（可能 5 分钟）没有单击任何单元格，然后单击时，模拟器严重崩溃并在 LogCat 中输出此内容：

10-11 11:45:22.591: ERROR/AndroidRuntime(255): Uncaught handler: thread main exiting due to uncaught exception
10-11 11:45:22.682: ERROR/AndroidRuntime(255): java.lang.RuntimeException: Unable to start activity ComponentInfo{se.ribit.bb/se.ribit.bb.TownBrowser}: android.database.sqlite.SQLiteException: Unable to close due to unfinalised statements
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.os.Looper.loop(Looper.java:123)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread.main(ActivityThread.java:4363)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at java.lang.reflect.Method.invokeNative(Native Method)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at java.lang.reflect.Method.invoke(Method.java:521)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at dalvik.system.NativeStart.main(Native Method)
10-11 11:45:22.682: ERROR/AndroidRuntime(255): Caused by: android.database.sqlite.SQLiteException: Unable to close due to unfinalised statements
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteDatabase.dbclose(Native Method)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteDatabase.onAllReferencesReleased(SQLiteDatabase.java:254)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteClosable.releaseReference(SQLiteClosable.java:42)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteProgram.onAllReferencesReleasedFromContainer(SQLiteProgram.java:76)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteDatabase.closeClosable(SQLiteDatabase.java:799)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.database.sqlite.SQLiteDatabase.close(SQLiteDatabase.java:786)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at se.ribit.bb.LocationDB.updateTowns(LocationDB.java:291)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at se.ribit.bb.AVApplication.httpCommand(AVApplication.java:217)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at se.ribit.bb.TownBrowser.onCreate(TownBrowser.java:44)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
10-11 11:45:22.682: ERROR/AndroidRuntime(255):     ... 11 more

任何人都可以告诉我这是怎么回事？

Answer 1

您是否在 OnDestroy 方法中使用 释放了 Cursor

stopManagingCursor(c);

？

哦，你应该使用 CursorLoader，startManagingCursor() 已弃用。

Loader API 通过兼容性包提供给旧设备，请参阅：http://mobile.tutsplus.com/tutorials/android/android-compatibility-working-with-fragments/

Answer 2

不看代码很难知道，但您可能在关闭游标之前关闭数据库： SQLite Exception in android

这是错误所在，因此您应该检查那里：在 se.ribit.bb.LocationDB.updateTowns(LocationDB.java:291)