有沒有辦法限制NSNotification？

Question

我使用NSNotification在切換開關時發送通知位置開始更新地圖上的註釋。我的問題是，我有8個開關，當用戶更改少數開關的位置時，多次映射更新。如何限制一個通知？

- (IBAction)saveSwitch:(id)sender 
{ 

    [[NSNotificationCenter defaultCenter] postNotificationName:@"MyAppSettingsChanged" object:self userInfo:nil]; 


    NSUserDefaults *defs1 = [NSUserDefaults standardUserDefaults]; 
    [defs1 setBool: blackSwitch.on forKey: @"blackKey"]; 

    NSUserDefaults *defs2 = [NSUserDefaults standardUserDefaults]; 
    [defs2 setBool: greenSwitch.on forKey: @"greenKey"]; 

    NSUserDefaults *defs3 = [NSUserDefaults standardUserDefaults]; 
    [defs3 setBool: purpleSwitch.on forKey: @"purpleKey"]; 

    NSUserDefaults *defs4 = [NSUserDefaults standardUserDefaults]; 
    [defs4 setBool: orangeSwitch.on forKey: @"orangeKey"]; 

    NSUserDefaults *defs5 = [NSUserDefaults standardUserDefaults]; 
    [defs5 setBool: blueSwitch.on forKey: @"blueKey"]; 

    NSUserDefaults *defs6 = [NSUserDefaults standardUserDefaults]; 
    [defs6 setBool: redSwitch.on forKey: @"redKey"]; 

    NSUserDefaults *defs7 = [NSUserDefaults standardUserDefaults]; 
    [defs7 setBool: darkblueSwitch.on forKey: @"darkblueKey"]; 

    NSUserDefaults *defs8 = [NSUserDefaults standardUserDefaults]; 
    [defs8 setBool: yellowSwitch.on forKey: @"yellowKey"]; 

    [[NSUserDefaults standardUserDefaults] synchronize]; 

} 

另一種觀點認爲

- (void)viewWillAppear:(BOOL)animated 
{ 
    [super viewWillAppear:animated]; 

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onAppSettingsChanged:) name:@"MyAppSettingsChanged" object:nil]; 

} 

更新註釋

- (void) onAppSettingsChanged:(NSNotification *)notification { 

    NSLog(@"Settings was changed"); 

    //Create the thread 
    [NSThread detachNewThreadSelector:@selector(loadPList) toTarget:self withObject:nil]; 

} 

Answer 1

您必須更新一些BOOL EAN值，表明你是不是正在處理的最新情況，並進行相應處理。 I.E.

- (void) onAppSettingsChanged:(NSNotification *)notification { 
  NSLog(@"Settings was changed"); 
    if (!myBoolToIndicateProcessing) { 
   //Create the thread 
     myBoolToIndicateProcessing = YES; 
   [NSThread detachNewThreadSelector:@selector(loadPList) toTarget:self withObject:nil]; 
    } 
} 

然後，當重新加載完成後，將BOOL設置回NO。