objective-c - NSNotificationCenter未发送通知

Question

我正在开发一个跟踪成就的系统，为此，我使用NSNotificationCenter。当成就在应用程序中的对象中解锁时，将向JMAchievementHandler发送通知，该通知将字符串设置为YES并将进度保存在NSUserDefaults中。我的问题是通知可能无法正常工作。这是我在JMAchievementHandler中的代码:

- (id)init {
    self = [super init];
    if (self) {

        //Set strings to NO
        achievementOne = @"NO";
        achievementTwo = @"NO";
        achievementThree = @"NO";
        achievementFour = @"NO";

        //Add observers
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveNotificationWithName:) name:@"achievement1" object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveNotificationWithName) name:@"achievement2" object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveNotificationWithName) name:@"achievement3" object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveNotificationWithName) name:@"achievement4" object:nil];

        //Add observer to observe delegate methods
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveNotificationFromDelegate:) name:@"notificationLaunch" object:nil];

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

    }
    return self;
}

- (void)receiveNotificationWithName:(NSNotification *)notification {
    if ([[notification name] isEqualToString:@"achievement1"] || [achievementOne isEqualToString:@"NO"]) {

        //unlock achievement
        NSLog(@"%@ is unlocked", [notification name]);
        achievementOne = @"YES";
    }

    else if ([[notification name] isEqualToString:@"achievement2"] || [achievementTwo isEqualToString:@"NO"]) {

        //unlock achievement
        NSLog(@"%@ is unlocked", [notification name]);
        achievementTwo = @"YES";
    }

    else if ([[notification name] isEqualToString:@"achievement3"] || [achievementThree isEqualToString:@"NO"]) {

        //unlock achievement
        NSLog(@"%@ is unlocked", [notification name]);
        achievementThree = @"YES";
    }

    else if ([[notification name] isEqualToString:@"achievement4"] || [achievementFour isEqualToString:@"NO"]) {

        //unlock achievement
        NSLog(@"%@ is unlocked", [notification name]);
        achievementFour = @"YES";
    }
}

- (void)receiveNotificationFromDelegate:(NSNotification *)notificationDelegate
{
    if ([[notificationDelegate name] isEqualToString:@"notificationLaunch"]) {

        [self loadDataOnLaunch];
    }
    else if ([[notificationDelegate name] isEqualToString:@"notificationEnterBackground"]) {
        [self saveDataOnExit];
    }
}

- (void)loadDataOnLaunch
{
    NSLog(@"loadDataOnLaunch");
}

- (void)saveDataOnExit
{
    NSLog(@"saveDataOnExit");
}

当我尝试发布通知时，未调用NSLogs。我使用以下代码从 AppDelegate和 ViewController发送通知。

- (void)achievement1ButtonPressed:(id)sender {

    [[NSNotificationCenter defaultCenter] postNotificationName:@"achievement1" object:self userInfo:nil];
}

我希望你们能帮助我。非常感谢

乔纳斯

Answer 1

您甚至有一个名为receiveNotificationWithName的方法吗？当您输入代码时，自动完成功能应该被驳倒了，改为提供receiveNotificationWithName:(除非您首先编写它，没有NSNotification*，然后再添加它...

无论如何，两者之间有很大的不同。另外，您的处理程序有故障。您应该重新访问该代码。

有很多原因喜欢使用块，这就是其中之一。您可以将代码正确地放在注册中，而不必担心给出错误的选择器。

[[NSNotificationCenter defaultCenter] addObserverForName:@"achievement1"
                                                  object:nil
                                                   queue:nil
                                              usingBlock:^{
    // Handle achievement1 right in this little block.
}];

这些看起来像是一次通知，因此，如果您想在运行一次后注销通知处理程序，请执行此操作(请注意 __block)。

__block id achievement1 = [[NSNotificationCenter defaultCenter]
                              addObserverForName:@"achievement1 ":^{
                                          object:nil
                                           queue:nil
                                      usingBlock:^{
    // Handle achievement1 right in this little block.

    // Remove observer from notification center
    [[NSNotificationCenter defaultCenter] removeObserver:achievement1];
}];