完成两种方法后如何编写执行方法(ios)

Question

我有2个方法可以在一个按钮点击事件上执行,method1:并且method2:.Both有网络调用,因此无法确定哪个方法将首先完成.

我必须methodFinish在完成method1:和method2之后执行另一个方法:

-(void)doSomething
{

   [method1:a];
   [method2:b];

    //after both finish have to execute
   [methodFinish]
}

除了典型的以外,我怎样才能做到这一点 start method1:-> completed -> start method2: ->completed-> start methodFinish

阅读有关街区的信息.我是块新手.可以帮我写一篇文章吗？任何解释都会非常有用.谢谢.

Answer 1

这就是调度组的用途.

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_group_t group = dispatch_group_create();

// Add a task to the group
dispatch_group_async(group, queue, ^{
  [self method1:a];
});

// Add another task to the group
dispatch_group_async(group, queue, ^{
  [self method2:a];
});

// Add a handler function for when the entire group completes
// It's possible that this will happen immediately if the other methods have already finished
dispatch_group_notify(group, queue, ^{
   [methodFinish]
});

调度组是ARC管理的.它们由系统保留,直到它们的所有块运行,因此在ARC下它们的内存管理很容易.

另请参阅dispatch_group_wait()是否要在组完成之前阻止执行.