使用GCD单个页面多个网络请求的情况(依次调用接口),等待所有网络请求结束后,再刷新UI

 

#pragma mark - 单个页面多个网络请求的情况(依次调用接口),等待所有网络请求结束后,再刷新UI
- (void)loadHttpData{
    dispatch_group_t group = dispatch_group_create();
    dispatch_queue_t searialQueue = dispatch_queue_create("com.hmc.www", DISPATCH_QUEUE_SERIAL);
    
    dispatch_group_enter(group);
    dispatch_group_async(group, searialQueue, ^{
        // 网络请求一
        [WebRequest getDataSuccess:^(NSDictionary *dict) {
            dispatch_group_leave(group);
        } failure:^(NSError *err) {
            dispatch_group_leave(group);
        }];
    });
    
    dispatch_group_enter(group);
    dispatch_group_async(group, searialQueue, ^{
        // 网络请求二
        [WebRequest getDataSuccess:^(NSDictionary *dict) {
            dispatch_group_leave(group);
        } failure:^(NSError *err) {
            dispatch_group_leave(group);
        }];
    });
    
    dispatch_group_enter(group);
    dispatch_group_async(group, searialQueue, ^{
        // 网络请求三
        [WebRequest getDataSuccess:^(NSDictionary *dict) {
            dispatch_group_leave(group);
        } failure:^(NSError *err) {
            dispatch_group_leave(group);
        }];
    });
    
    //三个网络请求结束后,会进入这个方法,在这个方法中进行洁面的刷行
    dispatch_group_notify(group, searialQueue, ^{
        dispatch_async(dispatch_get_global_queue(0, 0), ^{
            dispatch_async(dispatch_get_main_queue(), ^{
                // 刷新UI
            });
        });
    });
}

 

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