安卓獲取當前系統棧頂的activity

最近經常要判斷當前第一個activity是哪一個activity，對此做一個記錄，下面貼上代碼
  

private boolean isTopActivity(String className) {

    ActivityManager manager = (ActivityManager)                         
    mContext.getSystemService(Context.ACTIVITY_SERVICE);

    ComponentName cn = manager.getRunningTasks(1).get(0).topActivity;

    String topActivityName = cn.getClassName(); Log.i(TAG,"topActivityName:" + topActivityName);

    return topActivityName.equals(className);

}