我有一个活动回来堆栈中的应用 - 乙 - ç - >ð - > E.现在，在活动E，我想知道，我是从导航后面堆活动。我怎么觉得这??

I have an application with activities back stack A -> B -> C -> D -> E. Now at activity E, I want to know the back stack activities that I navigated from. How do I find this??

推荐答案

的$ C $低于C可用于提取所有的任务和在后面堆栈中每个任务内的顶部的活性

The code below can be used to extract all the tasks and the top activity within each task in the back stack

ActivityManager m = (ActivityManager) ctx.getSystemService( ctx.ACTIVITY_SERVICE );
List<RunningTaskInfo> runningTaskInfoList =  m.getRunningTasks(10);
Iterator<RunningTaskInfo> itr = runningTaskInfoList.iterator();
while(itr.hasNext()){
    RunningTaskInfo runningTaskInfo = (RunningTaskInfo)itr.next();
    int id = runningTaskInfo.id;
    CharSequence desc= runningTaskInfo.description;
    int numOfActivities = runningTaskInfo.numActivities;
    String topActivity = runningTaskInfo.topActivity.getShortClassName();
}