得到栈顶的activity

得到栈顶的activity：

 

private String getTopActivity(){
		ActivityManager manager = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE);

		List<RunningTaskInfo> runningTaskInfos = manager.getRunningTasks(1);
		if (runningTaskInfos != null)
			return (runningTaskInfos.get(0).topActivity).toString();
		else
			return null;
	}