3
我確實調用了一個AsyncTask傳遞一個方法來執行,以確定一個方法從一個特定的id返回一個名爲NAME
的行。在doInBackground上調用數據庫查詢/原始查詢時,它返回一個空結果的遊標,甚至在TABLE有8條記錄時試圖用查詢SELECT * FROM TABLE
進行嘗試。這裏有什麼問題?查詢是否同步?如果是這樣,我應該如何編碼以防止這些問題?android sqlite查詢返回光標0結果
EDIT
...
final TextView tv = (TextView)findViewById(R.id.textView);
dao.retrieveMovieByIdAsync(1, new AsyncTaskCaller() {
@Override
public void execute(Movie result) {
tv.setText(result.get_Name());
}});
...
private class AsyncRetieveQuery extends AsyncTask<Method, Void, Movie>
{
private Object args;
private AsyncTaskCaller signal;
public AsyncRetieveQuery(Object args, AsyncTaskCaller signal) {
this.args = args;
this.signal = signal;
}
@Override
protected Movie doInBackground(Method... params) {
params[0].setAccessible(true);
try {
return (Movie) params[0].invoke(DBUtils.this, new Object[] {args});
} catch (Exception e) {
return null;
}
}
@Override
protected void onPostExecute(Movie result) {
signal.execute(result);
super.onPostExecute(result);
}
}
...
public void retrieveMovieByIdAsync(int id, AsyncTaskCaller resultMethod)
{
try {
new AsyncRetieveQuery(id,resultMethod).execute(DBUtils.class.getDeclaredMethod("retrieveMovieById", int.class));
} catch (NoSuchMethodException e) {}
}
...
private Movie retrieveMovieById(int id)
{
Cursor cursor = database.rawQuery("SELECT * FROM " + SQLiteHelper.TABLE_MOVIES_NAME + " WHERE _Id = ?", new String[] {String.valueOf(id)});
調試器總是與空結果
向我們展示一些代碼。 – 2013-02-19 23:08:37
如果您將rawQuery()的第二個參數設置爲null,那麼您的遊標是否仍然返回0結果?另外,你有沒有試圖擺脫WHERE子句?這在你的查詢中並不是真的需要嗎? – Barney 2013-02-19 23:41:47
我擺脫了where子句,仍然得到0結果... – 2013-02-20 00:10:09