Go back to activity with new variable

Question

Here is what I want:

1. In Activity No.1. some variables receive values (variable A and B)
2. Here the user launches Activity No.2. and sets a variable (variable C)
3. User presses a button that takes him back to Activity No.1.
4. Activity No.1. has now the value of all the three variables.

I can pass the variables to Activity No.2. with an intent and retrieve them there using a Bundle. But is it an appropriate way to open Activity No.1. by using basically the same lines that I used to start Activity No.2?

In Activity No.1:

Intent intent = new Intent(getApplicationContext(), ActivityNo2.class);
intent.putExtra("date", date);
intent.putExtra("filename", filename);
startActivity(intent);

In Activity No.2:

Bundle bundle = getIntent().getExtras();
String date = bundle.getString("date");
String filename = bundle.getString("filename");
String variableC = "somevalue";

What's the best way to return to Activity No.1. with the new variable?

Answer 1

Could you have a variable in class A (Activity 1), get an instance of class A(from class B[this is the singleton design pattern]) and set the value of that variable via a setMethod?

Answer 2

What you are doing would work but there is a better way. The way you are doing it is just creating more possible errors. And Android provides a solution for this type of occasion.

You can use startActivityForResult() to go to Activity 2. This will allow you to send a result back to Activity 1 with variable C.

As long as you have given the variables the correct scope in Activity 1 they will still be there when you return to onActivityResult().

This answer gives a little more explanation on how to use it.