Question

In my navigation the following sequence of activities can be produced: A,B,C,B,C,B,C, …, D.
D activity contains an overriden method for the Back-button, which sends user to the A activity with Intent.FLAG_ACTIVITY_CLEAR_TOP parameter.

Activity A receives a number of necessary extra parameters and my problem is that when I trigger startActivity in D activity with this CLEAR_TOP flag activity A doesn’t seem to get any previous extra or even launch onResume method.

Does it mean that CLEAR_TOP actually recreates the target activity instead of bringing up the old one ? And, is there any system-natural approach to restore those extra intent parameters in activity A when I launch it from activity D.

P.S. Right now the only choice I see is to manually fillin those previous necessary parameters when constructing intent object in D activity. Is it a way to go ?

Thanks.

Answer 1

Does it mean that CLEAR_TOP actually recreates the target activity
instead of bringing up the old one ?

When you use CLEAR_TOP flag,target Activity does not recreate,but when you use a new intent to appear Activity A,you can only get this new intent’s extras in Activity A.

And, is there any system-natural approach to restore those extra
intent parameters in activity A when I launch it from activity D?

You can save these extras in file,preferences or global application variables,when you leave Activity A.Or you can declare a static method in Activity A that save these extras in it and you would to invoke it from Activity D,before force to appear Activity A:
Activity A:

Public class A extends Activity{
...
public static void saveExtras(){
//save extras in file,preferences,...
}
...
}     

Activity D:

Public class D extends Activity{
...
public void forceActivityA(){
A.saveExtras();
Intent i = new Intent(this,A.class());
...
startActivity(i);
}
...
} 

Edit:
When Activity A appears again,it’s onCreate() method invokes again and here you can get intent that request it.Then you can get intent’s flag and compare it with 67108864(constant for CLEAR_TOP flag).If it equals to this constant you would to retrieve your data from your storage(file,preferences,…).To create global variables you can see this question.