android - java.lang.IllegalStateException : attempt to re-open an already-closed object(Tried closing )

Question

public int getRecordsCount() {
        String countQuery = "SELECT  * FROM " + TABLE_LOGIN;

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        if(cursor != null && !cursor.isClosed()){
            cursor.close();
        }   
        // return count

        return cursor.getCount();
    }

我正在尝试获取数据库中的记录总数，但数据库每次都因 java.lang.IllegalStateException:尝试重新打开已关闭的对象:android.database.sqlite 而崩溃。 SQLiteQuery (mSql = SELECT * FROM login) 。请帮我解决错误

  03-05 22:23:14.208: E/AndroidRuntime(4988): FATAL EXCEPTION: main
    03-05 22:23:14.208: E/AndroidRuntime(4988): java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT  * FROM login) 
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:34)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:64)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:283)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:264)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at com.ecomm.android.sqlite.DatabaseHandler.getRecordsCount(DatabaseHandler.java:123)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at com.ecomm.android.LaunchActivity.DataBaseImplementation(LaunchActivity.java:120)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at com.ecomm.android.LaunchActivity.onClick(LaunchActivity.java:98)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.view.View.performClick(View.java:2408)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.view.View$PerformClick.run(View.java:8816)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.os.Handler.handleCallback(Handler.java:587)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.os.Handler.dispatchMessage(Handler.java:92)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.os.Looper.loop(Looper.java:123)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at android.app.ActivityThread.main(ActivityThread.java:4627)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at java.lang.reflect.Method.invokeNative(Native Method)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at java.lang.reflect.Method.invoke(Method.java:521)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:876)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:634)
    03-05 22:23:14.208: E/AndroidRuntime(4988):     at dalvik.system.NativeStart.main(Native Method)
    03-05 22:23:15.608: I/binder_sample(4988): [android.app.IActivityManager,2,1395,com.ecomm.android,100]
    03-05 22:23:15.608: I/binder_sample(4988): Unknown binary event type 110
    03-05 22:23:15.608: I/binder_sample(4988): Binary log entry conversion failed

Answer 1

您应该在关闭光标之前调用 getCount()。

移动:

if(cursor != null && !cursor.isClosed()){
    cursor.close();
} 

下面:

 cursor.getCount();

像这样:

public int getRecordsCount() {
    int count = 0;
    String countQuery = "SELECT  * FROM " + TABLE_LOGIN;

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);



    if(cursor != null && !cursor.isClosed()){
        count = cursor.getCount();
        cursor.close();
    }   
    return count;
}