从sqlite数据库Android检索数据时捕获异常

Question

I have this on my DBHelper

public Cursor selectUser(String username){
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor res = db.rawQuery("SELECT * FROM user_tbl WHERE username = '" +
            username+"'", null);
    return res;
}

And i also have this try-catch block on my Activity.

DBHelper mydb;
Cursor res;
user = LoginActivity.usernamee;        
    try{
                res = mydb.selectUser(user);
                if(res.getCount() > 0){
                    String fullnamee = res.getString(res.getColumnIndex(DBHelper.USER_NAME));
                    fullname.setText(fullnamee);
                    fullname.setFocusable(false);
                    fullname.setClickable(false);
                }

            }catch(Exception e){
                System.out.println("Error retrieving database record.");
            }

However, I am getting the catch exception. What I am trying to do is that, I would like to check my database where username is equal to LoginActivity.usernamee . Then display the full name of the user from my database table to my Android text view.

I would like to ask for assistance. Thank you!

Answer 1

i think you are missing "moveToFirst"

SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery("SELECT * FROM user_tbl WHERE username = '" + username + "'", null);

if(res.getCount() > 0){
  res.moveToFirst();
  String fullnamee = res.getString(res.getColumnIndex(DBHelper.USER_NAME));
  // do what you want
}