Android Studio SQL - 如何在字符串数组中返回数据

Question

我这里有一个 SQL 方法。我想在 String[] 数组中返回数据。

我该怎么做？

谢谢！

public String[] getLikedSongs() {
        SQLiteDatabase db = this.getReadableDatabase();
        String[] LikeSong;
        Cursor cursor = db.rawQuery(" SELECT " + COL_4 + " FROM " + Table_Name + " WHERE " + COL_4 + " IS NOT NULL", null);
        while (cursor.moveToNext()) {
            String note = cursor.getString(0);
        }
        cursor.close();
        db.close();
        return LikeSong;
    }

Answer 1

您必须定义数组的长度，这只能在光标获取所有行之后完成。然后将其长度设置为光标的行数。
然后在while循环内设置数组的项：

public String[] getLikedSongs() {
    String[] LikeSong = null;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery("SELECT " + COL_4 + " FROM " + Table_Name + " WHERE " + COL_4 + " IS NOT NULL", null);
    if (cursor.getCount() > 0) {
        LikeSong = new String[cursor.getCount()];
        int i = 0;
        while (cursor.moveToNext()) {
            LikeSong[i] = cursor.getString(0);
            i++;
        }
    }
    cursor.close();
    db.close();
    return LikeSong;
}