在设备上使用 sqlite 数据库时出现 NullPointerException，但模拟器工作正常

问：

我正在尝试使用预定义的数据库 SQLite 开发一个字典应用程序，这是它崩溃时的日志。

2019-11-23 08:26:40.432 16132-16349/offline.english.dictionary W/CrashlyticsCore: Cannot send reports. Settings are unavailable.
2019-11-23 08:26:40.433 16132-16132/offline.english.dictionary E/UncaughtException: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.database.CursorWindow.getNumRows()' on a null object reference
        at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:162)
        at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:149)
        at android.support.v4.widget.CursorAdapter.getCount(CursorAdapter.java:217)
        at android.widget.AutoCompleteTextView$PopupDataSetObserver$1.run(AutoCompleteTextView.java:1416)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7073)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)

这是SQLITECURSOR.java，它显示错误行：162

catch (RuntimeException ex) {
        closeWindow();
        throw ex;
    }
}

根据崩溃日志，这是SQLiteCursor.java：149

 mCount = mQuery.fillWindow(mWindow, requiredPos, requiredPos, true);

根据崩溃日志，这是 CursorAdapter.java：217

private final Runnable updateRunnable = new Runnable() {
        @Override
        public void run() {
            final AutoCompleteTextView textView = mViewReference.get();
            if (textView == null) {
                return;
            }
            final ListAdapter adapter = textView.mAdapter;
            if (adapter == null) {
                return;
            }
            textView.updateDropDownForFilter(adapter.getCount());
        }
    };
  }
}

这是处理程序.java：873,99 根据崩溃日志

 private static void handleCallback(Message message) {
    message.callback.run();
}
public void dispatchMessage(Message msg) {
    if (msg.callback != null) {
        handleCallback(msg);
    } else {
        if (mCallback != null) {
            if (mCallback.handleMessage(msg)) {
                return;
            }
        }
        handleMessage(msg);
    }
}

这是Looper.java：214，根据崩溃报告。

if (logSlowDispatch) {
            showSlowLog(slowDispatchThresholdMs, dispatchStart, dispatchEnd, "dispatch", msg);
        }

        if (logging != null) {
            logging.println("<<<<< Finished to " + msg.target + " " + msg.callback);
        }