应用终止后，使用NSNotification在UIViewController中处理UILocalNotification [英] Handle UILocalNotification in UIViewController using NSNotification after the app has been terminated

问题描述

我正在使用UILocalNotification，我想通知我的一个控制器即使已终止该应用程序，也已收到通知.

I'm working with UILocalNotification and I would like to notify one of my controller that the notification has been received even if the app has been terminated.

在我的appDelegate中，我实现了此功能:

In my appDelegate I implemented this function:

-(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification
{
    if ([application applicationState] == UIApplicationStateInactive) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"localNotificationReceived" object:notification.userInfo];
    }
}

在我的UIViewController中，我在viewDidLoad方法上实现了观察者

In my UIViewController I implemented the observer on the viewDidLoad method

- (void)viewDidLoad
{
    [super viewDidLoad];

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

}

当应用程序在后台运行时，它可以完美运行.由于viewDidLoad方法已经被调用并且观察者正在等待.

It works perfectly when the app run in background. Since the viewDidLoad method has already been called and the Observer is waiting..

问题是我杀死该应用程序时.然后我的控制器的观察者消失了，并且从未调用didlocalNotificationReceived方法.

The issue is when I kill the app. Then the observer of my controller is gone and the didlocalNotificationReceived method is never called.

我认为这是因为当我收到localNotification并再次运行该应用程序时. didReceiveLocalNotification:方法在我的UIViewController的viewDidLoad之前调用.然后在PostNotificationName之后创建观察者，然后观察者什么也没收到.

I think that it's because when I receive the localNotification and run the app again. The didReceiveLocalNotification: method is called before the viewDidLoad of my UIViewController. Then the observer is created after the PostNotificationName then the observer receives nothing.

我想知道是否存在一些最佳实践或模式来处理此类问题.

I would like to know if there is some best practices or pattern to handle this kind of issue.

我知道didFinishLaunchingWithOptions方法是在didlocalNotificationReceived之前调用的，因此可能需要做一些事情.

I know that the didFinishLaunchingWithOptions method is called before didlocalNotificationReceived so there is probably something to do there.

更新:

我还发现应用何时终止.点击通知后，它会打开应用程序，调用函数didFinishLaunchingWithOptions，但不要调用didReceiveLocalNotification.因此，我认为我将以不同的方式处理这两种情况.

I also discovered that when is app is terminated. Once you tap the notification, It opens the app, call the function didFinishLaunchingWithOptions but never call didReceiveLocalNotification. So I think that I'm gonna handle both cases differently.

推荐答案

好，我找到了答案.

我实际上是手动初始化情节提要，在发布NSNotification

I actually, initialize manually my storyboard, and be cautious that I initialize my main view before posting the NSNotification

我的appDelegate中的didFinishLaunchingWithOptions:方法看起来像这样:

My didFinishLaunchingWithOptions: method in my appDelegate looks like that:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]];
    UIViewController *vc =[storyboard instantiateInitialViewController]; //call the initWithCoder: method of my controller

    if (launchOptions[UIApplicationLaunchOptionsLocalNotificationKey]) {
        UILocalNotification *localNotification = launchOptions[UIApplicationLaunchOptionsLocalNotificationKey];
        [[NSNotificationCenter defaultCenter] postNotificationName:@"localNotificationReceived" object:localNotification.userInfo];
    }

    self.window.rootViewController = vc;
    [self.window makeKeyAndVisible];

    return YES;
}

然后在我的UIViewController中，我在initWithCoder:方法中而不是在viewDidLoad:

Then in my UIViewController I create the NSNotification observer in the initWithCoder: method instead of in viewDidLoad:

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didlocalNotificationReceived:) name:@"localNotificationReceived" object:nil];
    }
    return self;
}

- (void)didlocalNotificationReceived:(NSNotification *)notification
{
    //Execute whatever method when received local notification
}

当应用程序未终止时，我仍然使用didReceiveLocalNotification:方法:

And when the app is not killed I still use the didReceiveLocalNotification: method:

-(void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification
{
    if ([application applicationState] == UIApplicationStateInactive) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"localNotificationReceived" object:notification.userInfo];
    }
}

我不确定这是否是最佳做法.但是效果很好！

I'm not sure if it's the best practice. But it works well !

希望这会有所帮助:)

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