从AppDelegate发送通知到ViewController [英] Send a notification from AppDelegate to ViewController

问题描述

需要您的帮助.我将这些Delegate方法实现到AppDelegate.m:

need your help. I implement these Delegate Method to the AppDelegate.m:

    -(BOOL)application:(UIApplication *)application
           openURL:(NSURL *)url
 sourceApplication:(NSString *)sourceApplication
        annotation:(id)annotation {
    if (url != nil && [url isFileURL]) {
        //Valid URL, send a message to the view controller with the url
    }
    else {
        //No valid url
    }
    return YES;

但是现在，我需要的URL不是在AppDelegate中，而是在ViewController中.我如何发送" URL或如何将这些Delegate方法实现到ViewController?

But now, I need the URL not in the AppDelegate but in my ViewController. How I can "send" them the url or how I can implement these Delegate Method to the ViewController?

推荐答案

您可以使用NSNotificationCenter，如下所示:

you can use NSNotificationCenter as shown below:

首先在您的应用程序委托中将Notification发布为:

Firstly post Notification in your app delegate as :

NSDictionary *_dictionary=[NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:[NSString stringWithFormat:@"%d",newIndex],nil] forKeys:[NSArray arrayWithObjects:SELECTED_INDEX,nil]];

[[NSNotificationCenter defaultCenter] postNotificationName:SELECT_INDEX_NOTIFICATION object:nil userInfo:_dictionary];

然后将您要观察此通知的ViewController注册为

then register the ViewController you want to observe this notification as

/***** To register and unregister for notification on recieving messages *****/
- (void)registerForNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(yourCustomMethod:)
                                                 name:SELECT_INDEX_NOTIFICATION object:nil];
}

/*** Your custom method called on notification ***/
-(void)yourCustomMethod:(NSNotification*)_notification
{
    [[self navigationController] popToRootViewControllerAnimated:YES];
    NSString *selectedIndex=[[_notification userInfo] objectForKey:SELECTED_INDEX];
    NSLog(@"selectedIndex  : %@",selectedIndex);

}

在ViewDidLoad中将该方法调用为:

call this method in ViewDidLoad as :

- (void)viewDidLoad
{

    [self registerForNotifications];
}

，然后在UnLoad上通过调用以下方法删除此观察器:

and then on UnLoad remove this observer by calling this method :

-(void)unregisterForNotifications
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:SELECT_INDEX_NOTIFICATION object:nil];
}


-(void)viewDidUnload
{
    [self unregisterForNotifications];
}

希望它对您有帮助.

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