我有游标的问题在我的Android应用程序。 我有一个SQLiteDatabase返回我的光标,当我尝试用获取的值:
I have problems with Cursor in my Android application. I have a SQLiteDatabase that return me Cursor when I try to fetch the values with :
public Cursor fetchOption(long rowId) throws SQLException {
Cursor mCursor = mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_TITLE, KEY_BODY}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
但我不知道如何获取光标的字段的值。 如果我这样做:
But I don't know how to obtain the value of the field in the Cursor. If I do that :
String a = mOptionDb.fetchOption(0).getColumnName(0).toString();
String b = mOptionDb.fetchOption(0).getColumnName(1).toString();
String c = mOptionDb.fetchOption(0).getColumnName(2).toString();
予得到的列(_id,标题,正文),但不是值的名称。 我该如何解决?
I obtain the name of the columns (_id, title, body) but not the value. How can I resolve that?
感谢你提前为您解答。 迈克尔
Thank you in advance for your answer. Michaël
我想你可以忘记检查空。
I think you can forget about checking for null.
相反,检查是否有数据,然后使用光标访问的列:
Instead check if there is data and then access the columns using the cursor:
Cursor cursor = fetchOption(0);
if (cursor.moveToFirst()) // data?
System.out.println(cursor.getString(cursor.getColumnIndex("title"));
cursor.close(); // that's important too, otherwise you're gonna leak cursors
这也可能是有意义的阅读机器人教程。记事本教程似乎符合这个要求:http://developer.android.com/guide/tutorials/notepad/index.html