How to prevent going back to the previous activity?

Question

When the BACK button is pressed on the phone, I want to prevent a specific activity from returning to its previous one.

Specifically, I have login and sign up screen

Answer 1

Following solution can be pretty useful in the usual login / main activity scenario or implementing a blocking screen.

To minimize the app rather than going back to previous activity, you can override onBackPressed() like this:

@Override
public void onBackPressed() {
    moveTaskToBack(true);
}

moveTaskToBack(boolean nonRoot) leaves your back stack as it is, just puts your task (all activities) in background. Same as if user pressed Home button.

Parameter boolean nonRoot - If false then this only works if the activity is the root of a task; if true it will work for any activity in a task.