call custom Activity as startActivityForResult

In Activity A,

onItemClick() of GridView

//create a new intent...
Intent intent = new Intent();
intent.putInt("position",position);
setResult(RESULT_OK,intent);
//close this Activity...
finish();

in Caller Activity,

  @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent){
        super.onActivityResult(requestCode, resultCode, intent);
        Bundle extras = intent.getExtras();
        if(extras != null)
        int position = extras.getInt("position");
    }