试图重新查询一个已经关闭的游标——怎么了？答案

【问题标题】：Trying to requery an already closed cursor - what's wrong?试图重新查询一个已经关闭的游标——怎么了？
【发布时间】：2012-11-08 16:27:30
【问题描述】：

我的应用抛出错误：

11-08 17:19:40.800: E/AndroidRuntime(18592): java.lang.RuntimeException: Unable to resume activity {app.piotrek.learning/app.piotrek.learning.AddNewQuestion}: java.lang.IllegalStateException: trying to requery an already closed cursor  android.database.sqlite.SQLiteCursor@40f7f8a8
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2567)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2595)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1183)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.os.Looper.loop(Looper.java:137)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.ActivityThread.main(ActivityThread.java:4575)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at java.lang.reflect.Method.invokeNative(Native Method)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at java.lang.reflect.Method.invoke(Method.java:511)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at dalvik.system.NativeStart.main(Native Method)
11-08 17:19:40.800: E/AndroidRuntime(18592): Caused by: java.lang.IllegalStateException: trying to requery an already closed cursor  android.database.sqlite.SQLiteCursor@40f7f8a8
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.Activity.performRestart(Activity.java:4508)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.Activity.performResume(Activity.java:4531)
11-08 17:19:40.800: E/AndroidRuntime(18592):    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2557)
11-08 17:19:40.800: E/AndroidRuntime(18592):    ... 10 more

当我进入另一个活动并点击“后退按钮”时，似乎出现了错误。我已经发现问题出在此处：

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

    db = new Database(getApplicationContext());

    db.open();

    fillSpinner(db.getAllEntriesSubjects(), spinnerSubject, DatabaseData.KEY_NAME);
    //long data = spinnerSubject.getSelectedItemId();
    //Log.v("ADDNEWQUESTION", "Wybrano: " + data);
    //fillSpinner(db.getAllEntriesTitles(), spinnerTitles);
    db.close();
}

public void fillSpinner(Cursor cs, Spinner spinner, String dane){
    startManagingCursor(cs);

    SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_spinner_item, cs, new String[] {dane}, new int[] {android.R.id.text1});
    mAdapter.setDropDownViewResource(android.R.layout.simple_spinner_item);
    spinner.setAdapter(mAdapter);
}

AFAIK，我没有关闭任何光标。那怎么了？

【问题讨论】：

标签： android cursor

【解决方案1】：

从onResume 方法中删除db.close(); 并将其添加到onPause() 方法中。希望对您有所帮助。

【讨论】：

那么，如果我想在点击“返回按钮”后运行 onCreate() 怎么办？当我在另一个活动中时如何杀死活动？
您不应该杀死您的活动，最好将必要的代码移至 onStart() 或 onResume()。要杀死 Activity，请使用 finish() 方法。

【解决方案2】：

试试这个..

public void onBackPressed() {

    Intent i = new Intent(getApplicationContext(), AddNewQuestion.class);
    startActivity(i);
    finish();
    super.onStop();

}

【讨论】：