在 往CCLayer裡面加 Notification通知的時候，一定要加在OnEnter和OnExit裡面

    在 往CCLayer裡面加  Notification通知的時候，一定要加在OnEnter和OnExit裡面，不要加在init和 dealloc上面，因為

很多時候CCLayer是通過node方法產生的，在切換layer的時候，dealloc不一定會調用，這樣會導致一個layer多次註冊一個通知，這樣導致，如果發送一個通知，會多次調用通知響應函數，導致問題，切記。

   例子代碼如下：

   

-(void)  onEnter{    //註冊新玩家讀取通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onReloadPlayerVec:) name:Str_NSNotification_FetchPlayerChairInfo object:nil];        //註冊新使用者基本資料通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onNewUserBasicInfo:) name:Str_NSNotification_NewUserBasicInfo object:nil];            //註冊新使用者其他資料通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onNewUserOtherInfo:) name:Str_NSNotification_NewUserOtherInfo object:nil];            //註冊玩家退出當前桌子的通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onPlayerExitTable:) name:Str_NSNotification_PlayerExitTable object:nil];        //註冊 公聊  訊息  通知    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onPublicMsg:) name:Str_NSNotification_PublicMsg object:nil];                [super  onEnter];}- (void)  onExit{    [[NSNotificationCenter defaultCenter] removeObserver:self name:Str_NSNotification_FetchPlayerChairInfo object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:Str_NSNotification_NewUserBasicInfo object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:Str_NSNotification_NewUserOtherInfo object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:Str_NSNotification_PlayerExitTable object:nil];        [[NSNotificationCenter defaultCenter] removeObserver:self name:Str_NSNotification_PublicMsg object:nil];                [self  clearUp];        [super  onExit];}