Question

我想同步异步方法调用及其委托调用。

例如：

foo 在完成带有结果的操作后调用 bar 。

//foo is an aync method..resides somewhere in external lib
[myObj foo:self action:@selector(bar:) param1:one param2:two];


// delegate
- (void) bar: (int) value {

    // Do something with the int result

    int result = value;    
}

我需要同步 foo 和 bar 的执行。这样的事情（没有修改 foo ）。

-(bool) perform_foo_bar {

   int result = [myObj foo_bar:param1:one param2:two]

   if (result == 1) 
   {
     return true;
   }
   else
   {
     return false; 
   }
}

是否可以使用大型中央调度（GCD）例程来实现这一目标？

Answer 1

你的问题很模糊，所以我为你提供了一个通用的解决方案，让你了解如何使用GCD同步多个线程。我希望它对您有所帮助，您可以在真实的代码中插入这个想法。

dispatch_group_t _group = dispatch_group_create();

dispatch_group_async(_group, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSLog(@"procedure 1, a long runtime is being simulated in 5 secs, but you can put anything here instead.");
    [NSThread sleepForTimeInterval:5.f];
    NSLog(@"procedure 1 is done...");
});

dispatch_group_async(_group, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSLog(@"procedure 2, a longer runtime is being simulated in 10 secs, but you can put anything here instead.");
    [NSThread sleepForTimeInterval:10.f];
    NSLog(@"procedure 2 is done...");
});

dispatch_group_notify(_group, dispatch_get_main_queue(), ^{
    NSLog(@"both procedures have been done.");
});

在iOS中同步异步方法调用及其deletgate调用

1 个答案: