如何在android中关闭光标答案

【问题标题】：How to close a cursor in android如何在android中关闭光标
【发布时间】：2012-10-22 14:58:16
【问题描述】：

如何关闭游标，每次调用数据库时都会显示此错误

10-18 03:29:52.191: E/Cursor(426): Finalizing a Cursor that has not been deactivated or closed. database = /data/data/standard.internet.marketing.mymovingfriend/databases/mymovingfriend, table = movingname, query = SELECT _id, movename, movedate FROM movingname WHERE movename= 'ok'
10-18 03:29:52.191: E/Cursor(426): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteCursor.<init>(SQLiteCursor.java:210)
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53)
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
10-18 03:29:52.191: E/Cursor(426):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
10-18 03:29:52.191: E/Cursor(426):  at standard.internet.marketing.mymovingfriend.SQLHandler.checkMove(SQLHandler.java:1094)
10-18 03:29:52.191: E/Cursor(426):  at standard.internet.marketing.mymovingfriend.ListMovingNames$3.onKey(ListMovingNames.java:98)
10-18 03:29:52.191: E/Cursor(426):  at android.view.View.dispatchKeyEvent(View.java:3735)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:788)
10-18 03:29:52.191: E/Cursor(426):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1667)
10-18 03:29:52.191: E/Cursor(426):  at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1102)
10-18 03:29:52.191: E/Cursor(426):  at android.app.Activity.dispatchKeyEvent(Activity.java:2063)
10-18 03:29:52.191: E/Cursor(426):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1643)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewRoot.deliverKeyEventToViewHierarchy(ViewRoot.java:2471)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2441)
10-18 03:29:52.191: E/Cursor(426):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1735)
10-18 03:29:52.191: E/Cursor(426):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-18 03:29:52.191: E/Cursor(426):  at android.os.Looper.loop(Looper.java:123)
10-18 03:29:52.191: E/Cursor(426):  at android.app.ActivityThread.main(ActivityThread.java:4627)
10-18 03:29:52.191: E/Cursor(426):  at java.lang.reflect.Method.invokeNative(Native Method)
10-18 03:29:52.191: E/Cursor(426):  at java.lang.reflect.Method.invoke(Method.java:521)
10-18 03:29:52.191: E/Cursor(426):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-18 03:29:52.191: E/Cursor(426):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-18 03:29:52.191: E/Cursor(426):  at dalvik.system.NativeStart.main(Native Method)

我尝试这样做以关闭光标

public Cursor getMove(){
        String[] columns = new String[]{KEY_ID1, KEY_MOVENAME};
        Cursor cursor = ourDatabase.query(DATABASE_TABLE1, columns, null, null, null, null, null);
        cursor.close();
        return cursor;
    }

现在的问题是它说

10-18 03:47:53.921: E/AndroidRuntime(545): FATAL EXCEPTION: main
10-18 03:47:53.921: E/AndroidRuntime(545): java.lang.RuntimeException: Unable to start activity ComponentInfo{standard.internet.marketing.mymovingfriend/standard.internet.marketing.mymovingfriend.ListMovingNames}: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT _id, movename FROM movingname) 
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.os.Looper.loop(Looper.java:123)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread.main(ActivityThread.java:4627)
10-18 03:47:53.921: E/AndroidRuntime(545):  at java.lang.reflect.Method.invokeNative(Native Method)
10-18 03:47:53.921: E/AndroidRuntime(545):  at java.lang.reflect.Method.invoke(Method.java:521)
10-18 03:47:53.921: E/AndroidRuntime(545):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-18 03:47:53.921: E/AndroidRuntime(545):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-18 03:47:53.921: E/AndroidRuntime(545):  at dalvik.system.NativeStart.main(Native Method)
10-18 03:47:53.921: E/AndroidRuntime(545): Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT _id, movename FROM movingname) 
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:34)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:64)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:283)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:264)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.widget.CursorAdapter.getCount(CursorAdapter.java:132)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.widget.ListView.setAdapter(ListView.java:436)
10-18 03:47:53.921: E/AndroidRuntime(545):  at standard.internet.marketing.mymovingfriend.ListMovingNames.allFunctions(ListMovingNames.java:57)
10-18 03:47:53.921: E/AndroidRuntime(545):  at standard.internet.marketing.mymovingfriend.ListMovingNames.onCreate(ListMovingNames.java:36)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-18 03:47:53.921: E/AndroidRuntime(545):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
10-18 03:47:53.921: E/AndroidRuntime(545):  ... 11 more

有什么解决办法吗？

【问题讨论】：

不要关闭它，如果您以后想使用它。从它读取所需的所有数据后，关闭它。

标签： android android-sqlite android-cursor

【解决方案1】：

您必须保持光标打开，直到您不再需要其中的数据。一旦您不再需要来自光标的数据，您只需：

cursor.close();

但是在 Activity 中处理数据的一种更简洁的方法是实现 LoaderManager。这样做，您就不必担心管理游标状态。相反，Android 可以有效地为您完成。

【讨论】：

【解决方案2】：

这行代码解决了一切

  Cursor c = null;
            try {
                .....
                }
            } finally {
                if(c != null){
                    c.close();
                }       
            }

            return items;
        }

【讨论】：