android – 获取光标的结果并将其转换为TextView的字符串
作者:互联网
这是我的查询:
Cursor nextdate(String Date) {
SQLiteDatabase db = this.getReadableDatabase();
String[] params = new String[]{String.valueOf(Date)};
Cursor cur = db.rawQuery(" SELECT MIN (" + colDateDue + ") FROM " + PAYMENTS + " WHERE " + colDateDue + ">=?", params);
cur.moveToFirst();
return cur;
}
我想在TextView中显示该查询的结果,但我不知道如何,所以我自然而然地寻找答案.我找到了几个答案并提出了这个问题:
DatabaseHelper db = new DatabaseHelper(this);
String str = "";
if (c!= null) {
if (c.moveToFirst()) {
str = c.getString(c.getColumnIndex(db.colDateDue);
}
}
TextView.setText(str);
但是我得到了错误
Caused by: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
这让我有点困惑,因为通常修复该错误是使用cur.moveToFirst();这两种情况都使用了……我到底做错了什么?
解决方法:
试试这样:
将列索引保持为0,因为该游标只有一列.
DatabaseHelper db = new DatabaseHelper(this);
String str = "";
if (c!= null) {
if (c.moveToFirst()) {
str = c.getString(0);
}
}
TextView.setText(str);
标签:android,sqlite,android-cursor 来源: https://codeday.me/bug/20190609/1205104.html