startActivityForResult

FirstActivity：

Intent intent = new Intent(FirstActivity.this, SecondActivity.class);

startActivityForResult(intent, 1);

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

switch (requestCode) {

case 1:

if (resultCode == RESULT_OK) {

String returnedData = data.getStringExtra("data_return");

Log.d("FirstActivity", returnedData);

}

break;

default:

}

}

SecondActivity：

Intent intent = new Intent();

intent.putExtra("data_return", "Hello FirstActivity");

setResult(RESULT_OK, intent);

finish();