Sending data back to the Main Activity in Android

Question

I have two activities: main activity and child activity.
When I press a button in the main activity, the child activity is launched.

Now I want to send some dat

Answer 1

FirstActivity uses startActivityForResult:

Intent intent = new Intent(MainActivity.this,SecondActivity.class);
startActivityForResult(intent, int requestCode); // suppose requestCode == 2

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 2)
    {
        String message=data.getStringExtra("MESSAGE");
    }
}

On SecondActivity call setResult() onClick events or onBackPressed()

Intent intent=new Intent();
intent.putExtra("MESSAGE",message);
setResult(Activity.RESULT_OK, intent);