Cursor index error while retrieving column data in variable

I am trying to retrieve username from database table when i successfully login my application and show that on my home activity. I am trying to do this through cursor but i am not retrieving the column data. Any suggestions or help please.

Login function

public String loginUsers(String email,String pwd)
{
Cursor mCursor = database.rawQuery("SELECT * FROM " + DatabaseWrapper.FUNTUBE + " WHERE _email=? AND _password=?", new String[]{email,pwd});
 if (mCursor != null) {
 if(mCursor.getCount() > 0)
 {
 String name= mCursor.getString(mCursor.getColumnIndex("_username"));
 mCursor.close();
 return name;
 }
 }
 return null;
 }

Login.java

 String user=  FunTubeDBOperations.loginUsers(em, pwd);
 if(true){
 Toast.makeText(getApplicationContext(), "Login successfully!!", Toast.LENGTH_LONG).show();
 Intent intent = new Intent(login.this, home.class);
 intent.putExtra("name", user);
 startActivity(intent);
 finish();
 }