Android - Clearing Navigation Backstack

Question

I have 4 pages.

From page_1 > page_2 > page_3 > page_4.

Once the user reaches page_3 and clicks a button, it navigates to page_4. Once the button is clicked, I want to clear all the navigation history so when the user goes back on page_4, the app quits rather than going back to page_3.

I've tried:

    Intent intent = new Intent(this, page_4.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
    finish();

But nothing happens. I can still go back to page_3, page_2 etc. How do I make it so that when the user clicks on the button on page_3, he goes to page_4 and from page_4 there shouldn't be any navigation history?

Answer 1

I'm not sure that these methods will works for you. The first method is by adding FLAG_ACTIVITY_TASK_ON_HOME when you go to page_4 from page_3:

Intent intent = new Intent(this, page_4.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_TASK_ON_HOME);
startActivity(intent);

So once you press BACK button within page_4, it directs you to HOME activity (MainActivity) first, then you can press BACK button again to exit the app from this activity.

From the docs:

If set in an Intent passed to Context.startActivity(), this flag will cause a newly launching task to be placed on top of the current home activity task (if there is one). That is, pressing back from the task will always return the user to home even if that was not the last activity they saw. This can only be used in conjunction with FLAG_ACTIVITY_NEW_TASK.

The second way is, set android:noHistory="true" within the activity in manifest. Apply this attribute for page_1 till page_4. But this method has two disadvantages. First, your activity is completely has no back stack. The second, the activities you set with this attribute get destroyed once you press HOME button or when you get an incoming call. I never found this topic, so please CMIIW.