Question

Found more than 10 tutorials to “cursors” but I can’t understand that.
My question is: How can I read data from a database?

For example:
Database name: Test_Database
Table name: tbl_users
In it are two columns: id, user_name

Now I like to read the user_name with id 3
==> SELECT user_name FROM tbl_useres WHERE id = 3

How can I give that out to a TextView, Toast or Alert?

Answer 1

The best way to achieve this (at least my opinion ) is to create your custom SqliteDatabaseHelper and you can create a function like this :

public Cursor executeSQLQuery(String query){
    Cursor c = sqliteDb.rawQuery(query,null); // private static  SQLiteDatabase sqliteDb; 
    return c;
}

which returns Cursor and after that you can use this cursor like :

CustomDatabaseHelper dbHelper = new CustomDatabaseHelper(params...);
String sql = "SELECT name FROM cards WHERE id=2";
Cursor cursor = dbHelper.executeSQLQuery(sql);
if(cursor.getCount()==0){
  // do something when you don't have any data, show message or something like this
} else if(cursor.getCount()>0){
    for(cursor.move(0); cursor.moveToNext(); cursor.isAfterLast()){
       String getName = cursor.getString(cursor.getColumnIndex("name"));
    }
}

This is at least how I’m using Cursor to get data from Database.

Hope it helps.