Android 如何获取最顶端的Top Activity

public static class TopActivityInfo {
public String packageName = "";
public String topActivityName = "";
}

private TopActivityInfo getTopActivityInfo() {
ActivityManager manager = ((ActivityManager)GlobalConfig.getContext().getSystemService(Context.ACTIVITY_SERVICE));
TopActivityInfo info = new TopActivityInfo();
if (Build.VERSION.SDK_INT >= 21) {
List<ActivityManager.RunningAppProcessInfo> pis = manager.getRunningAppProcesses();
ActivityManager.RunningAppProcessInfo topAppProcess = pis.get(0);
if (topAppProcess != null && topAppProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
info.packageName = topAppProcess.processName;
info.topActivityName = "";
}
} else {
//getRunningTasks() is deprecated since API Level 21 (Android 5.0)
List localList = manager.getRunningTasks(1);
ActivityManager.RunningTaskInfo localRunningTaskInfo = (ActivityManager.RunningTaskInfo)localList.get(0);
info.packageName = localRunningTaskInfo.topActivity.getPackageName();
info.topActivityName = localRunningTaskInfo.topActivity.getClassName();
}
return info;
}