android - 为什么我会收到此 sqlite 错误？

Question

我在按下操作栏中的菜单时添加了一个 AlertDialog，以提示用户是否真的确定他想继续保存/删除我的 sqlite 中的项目列表，但我在下面收到此错误。我还尝试删除 AlertDialog，而是在用户按下操作栏中的菜单以通知他们刚刚执行的操作后干杯，但我仍然在下面遇到相同的错误。如果我删除 AlertDialog 或 Toast 消息，一切都会正常保存和删除我的 sqlite 中的项目。

09-22 10:26:09.865: E/AndroidRuntime(2341): FATAL EXCEPTION: main
09-22 10:26:09.865: E/AndroidRuntime(2341): java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: /data/data/com.usjr.sss/databases/subjecttaken
09-22 10:26:09.865: E/AndroidRuntime(2341):     at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at android.database.sqlite.SQLiteDatabase.delete(SQLiteDatabase.java:1489)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at com.usjr.sss.adapter.SubjectTakenDbAdapter.deleteAllSubjects(SubjectTakenDbAdapter.java:56)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at com.usjr.sss.activity.CourseFragmentActivity$2.onClick(CourseFragmentActivity.java:143)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at android.os.Looper.loop(Looper.java:137)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at android.app.ActivityThread.main(ActivityThread.java:5227)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at java.lang.reflect.Method.invokeNative(Native Method)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at java.lang.reflect.Method.invoke(Method.java:511)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
09-22 10:26:09.865: E/AndroidRuntime(2341):     at dalvik.system.NativeStart.main(Native Method)

这是我的代码:

public boolean onOptionsItemSelected(MenuItem item) {
    // The action bar home/up action should open or close the drawer.
    // ActionBarDrawerToggle will take care of this.
    if (drawerToggle.onOptionsItemSelected(item)) {
        return true;
    }
    // Handle action buttons
    switch (item.getItemId()) {
    case R.id.action_save_subjects:

        subjectTakenDbAdapter.open();

        /**
         * Delete from database all subjects taken if user does not select a
         * subject & clicks save button
         */
        if (arrayListSelectedSubject.isEmpty()) {
            new AlertDialog.Builder(this).setMessage("Are you sure?")
                    .setPositiveButton("OK", new OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog,
                                int which) {
                            subjectTakenDbAdapter.deleteAllSubjects();

                        }
                    }).show();

        } else {
            /**
             * Add subjects taken to database
             */
            for (int index = 0; index < arrayListSelectedSubject.size(); index++) {
                subjectTakenDbAdapter
                        .createSubjectTaken((arrayListSelectedSubject
                                .get(index)));
                Log.i("ADD SUBJECT TAKEN",
                        arrayListSelectedSubject.get(index));
            }// end for loop
        }// end if-else

        Cursor cursor = subjectTakenDbAdapter.fetchAllSubjectTaken();
        Log.i("SubjectTakenDbAdapter", String.valueOf(cursor.getCount()));
        subjectTakenDbAdapter.close();
        return true;

    default:
        return super.onOptionsItemSelected(item);
    }// end switch case
}// end onOptionsItemSelected

logcat 告诉我这个错误的原因是指向我的 CourseFragmentActivity.class 中的 java 第 143 行，这是这行代码:

subjectTakenDbAdapter.deleteAllSubjects();

我的 SubjectTakenDbAdapter.class 中的 java 第 56 行是这行代码:

return sqLiteDatabase.delete(DATABASE_TABLE, null, null) > 0;

Answer 1

此 onOptionsItemSelected 中的操作将完全执行直到结束，即使对话框打开也是如此。因此它将调用 subjectTakenDbAdapter.close();。再次打开适配器:

new AlertDialog.Builder(this).setMessage("Are you sure?")
                .setPositiveButton("OK", new OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog,
                            int which) {
                        subjectTakenDbAdapter.open();
                        subjectTakenDbAdapter.deleteAllSubjects();
                        subjectTakenDbAdapter.close();
                    }
                }).show();