ios - 如何处理这个 : There are five api requests running parallelly and 2nd request is dependent on 4th request's response

Question

我遇到了一个问题，我想知道更好的解决方法。

有五个 api 请求并行运行，第二个请求依赖于第四个请求的响应，但所有 5 个请求都已在运行。什么是更好的方法？

需要建议。提前致谢。

Answer 1

调度地面工作正常。

//create a dispatch group
dispatch_group_t serviceGroup = dispatch_group_create();

//request 1
dispatch_group_async(serviceGroup,queue,^{
    // some work here
});

//request 3
dispatch_group_async(serviceGroup,queue,^{
    // some work here
});

//request 5
dispatch_group_async(serviceGroup,queue,^{
    // some work here
});

//request 4
dispatch_group_enter(serviceGroup);
[something startWithCompletion:^() {
    //result
    dispatch_group_leave(serviceGroup);
    //request 2
}];