Transitions between activities?

Question

Android

Activity ONE, when I click on the buttons on it, I get into the THREE or FOUR activity, the same goes for the TWO activity. How to programmatically read from which activity I got into activity three or four, and when I press the back button (3), go to the activity from which I got here? starts instantly.

Answer 1

To identify (where it came from), you need to use Intent
When calling an activity, place data

Intent intent = new Intent(this, THREE.class);
intent.putExtra("activity","first");
startActivity(intent);

and in THREE and get

Intent intent = getIntent();
String activity = intent.getStringExtra("activity");

Source
for back button: stackoverflow.com/questions/6927628/android-starta...