How to clear current activity stack when start another activity which belong to another stack

Question

For example:A start B, B start C, A and C belongs to 'Hello'-stack, and B belongs to 'World'-stack, when user press back button in Activity C, it will return to A. Note1:B means a lot of activities , not just one activity, like A start B1,B1 start B2, B2 start B3....,Bn start C. Note2:I need Bs remain in stack until C has been launched , when user press back in B3, it should return to b2.

I actually have implemented this need by using startActivityForResult,and I just want to know is there any way using stack to implements this.

Answer 1

从B启动活动C时，只需调用finish（）即可。然后在活动C中覆盖onBackPressed（）。并添加代码以启动活动A。

Answer 2

When going from activity A to activity B, go as below:

 Intent i=new Intent(ActivityA.this,ActivityB.class);
 startActivity(i);

And as you want to open C from B but don't want B to be in stack, so do as below:

 Intent i=new Intent(ActivityB.this,ActivityC.class);
 startActivity(i);
 ActivityB.this.finish();

So automatically when backpressed on C, you will get A and not B.

Answer 3

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP); or intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK); works for me.