当您有多个入口点活动时，清除活动堆栈吗？

Question

I have an app which has multiple entry point activities. I want to be able to clear my activity stack programmatically. Imagine an app which requires user authentication, and the user wants to invalidate their session remotely (stolen device, for example).

In the case where an app has a single starting activity, we could just use:

Intent intent = new Intent(context, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

to get back to the root activity. But my app may have been launched from different entry points, and so there might be different activity classes at the root of the stack.

Some options:

1. Register a broadcast receiver in my base activity class which I can call from anywhere. In the handler, just call finish(), unwinding whatever stack may exist.
2. Use the frowned-upon System.exit().
3. In the above example, use Intent.FLAG_ACTIVITY_CLEAR_TASK in addition to the other two flags (but this is only available in api 11 and above...)

Thanks

Answer 1

You can check the name of activity at the root of the task stack and then start that activity with the FLAG_ACTIVITY_CLEAR_TOP. If this root activity is not the activity you want then start the activity you want in onCreate and call finish().
You can find the name of the root activity by

1. call getTaskId () to get the task id.
2. Obtain an ActivityManager object and call getRunningTasks to get a list of running tasks (check out the warning in the doc, I do not understand clearly)
3. When the task in the list match the id above you can get the activity in the root using the field baseActivity