Normally when we launch new activity, it’s previous activities will be kept in a queue like a stack of activities. So if you want to kill all the previous activities, just follow these methods.
Method:- 1
In API level 11 or greater, use FLAG_ACTIVITY_CLEAR_TASK and FLAG_ACTIVITY_NEW_TASK flag on Intent to clear all the activity stack.
Intent mIntent = new Intent(OldActivity.this, NewActivity.class);
// set the new task and clear flags
mIntent .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK)
startActivity(mIntent );