等待另一位代表的客观c块

Question

我有一个在iPhone应用程序上调用viewcontroller的watchkit应用程序。我有一个网络连接代表。我正在尝试使用一个块，这样我就不会将我的AppDelegate和我的视图控制器紧密地联系在一起。代表完成后如何通知我的阻止？

ViewController.m

-(void)getWatchDataWithCompletion:(void(^)(BOOL gotData))completion{
   [self setUpAppForWatch];
   completion(YES);
}

-(void)finishedMessageParse:(NSMutableData *)messageData{
   //the delegate is finish tell the block completion is done.

}

-(void)setUpAppForWatch{
   [network call];
}

AppDelegate.m

-(void)application:(UIApplication *)application handleWatchKitExtensionRequest:(NSDictionary *)userInfo reply:(void (^)
(NSDictionary *))reply{

[vc getWatchDataWithCompletion:^(BOOL gotData){
    if (gotData){
       //I'm done reply dictionary
       reply(@{@"data":serlizedData})
}];

Answer 1

有三种可能的方法。

; tldr - 参考第三个。否则 - 阅读所有内容，它可能会有用。

第一个

使用专用串行队列执行finished...方法和块的任务。如果finished...在块之前总是被称为，那么就足够了。如果不是 - 请查看第二个

使用View Controller的私有@property dispatch_queue_t privateSerialQueue;。

privateSerialQueue = dispatch_queue_create("PrivateQueue", DISPATCH_QUEUE_SERIAL);

比，像这样使用

-(void)getWatchDataWithCompletion:(void(^)(BOOL gotData))completion{
    [self setUpAppForWatch];
    dispatch_async(privateSerialQueue, ^(){
       completion(YES);
    });
}

-(void)finishedMessageParse:(NSMutableData *)messageData{
    dispatch_sync(privateSerialQueue, ^(void){
            //Here goes whatever you need to do in this method before block start
    });
    //the delegate is finish tell the block completion is done.
}

第二个

看一下dispatch_semaphore_t。将其设为View Controler的公共属性

@property (readonly) dispatch_semaphore_t semaphore

使用起始值0创建它。如果您的块在委托finished...方法之前运行并立即运行，如果finished已在块之前完成，则会让您等待。喜欢这个

self.semaphore = dispatch_semaphore_create(0); 

然后你可以这样使用它

-(void)finishedMessageParse:(NSMutableData *)messageData{
  //the delegate is finish tell the block completion is done.
  dispatch_semaphore_signal(self.semaphore);
}

[vc getWatchDataWithCompletion:^(BOOL gotData){
    if (gotData){
       //I'm done reply dictionary
       dispatch_semaphore_wait(vc.semaphore, DISPATCH_TIME_FOREVER);
       reply(@{@"data":serlizedData})
}];

第三个

在写上面两个=）时出现在我的脑海里 前两种的某种组合

使用视图控制器的私有属性 @property (readonly) dispatch_semaphore_t semaphore

以相同的方式初始化它，如第二个（起始值为0）

self.semaphore = dispatch_semaphore_create(0); 

像这样私下使用

-(void)getWatchDataWithCompletion:(void(^)(BOOL gotData))completion{
    [self setUpAppForWatch];
    dispatch_semaphore_wait(self.semaphore, DISPATCH_TIME_FOREVER);
    completion(YES);
}

-(void)finishedMessageParse:(NSMutableData *)messageData{
  //the delegate is finish tell the block completion is done.
  dispatch_semaphore_signal(self.semaphore);
}

P上。 S. Hope，它可以帮助您达到目的。随意问一些不清楚的事情

Answer 2

在viewcontroller中添加新属性：

@property (nonatomic, strong) void(^completion)(BOOL gotData);


-(void)getWatchDataWithCompletion:(void(^)(BOOL gotData))completion{
   [self setUpAppForWatch];
   self.completion = completion;
}

-(void)finishedMessageParse:(NSMutableData *)messageData{
    if (self.completion){
        self.completion(YES);
    }
}