iOS开发网络篇：GCD实战之多个网络请求的并发

GCD实战之多个网络请求的并发

第一种GCD 方式：

    // 创建信号量    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);    // 创建全局并行    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);    dispatch_group_t group = dispatch_group_create();    dispatch_group_async(group, queue, ^{        // 请求一        [loginCode getUserInfoWithNick:nil andUserId:kUserId onSuc:^(id data) {            NSLog(@"yue");            dispatch_semaphore_signal(semaphore);        } andFail:^(NSError *error) {               }];    });    dispatch_group_async(group, queue, ^{        // 请求二        [CommodityViewModel getPriceTransformForIntegral:nil onSuccess:^(id data) {            NSLog(@"duihuan11");            dispatch_semaphore_signal(semaphore);        } onFailure:^(NSError *error) {        }];    });    dispatch_group_async(group, queue, ^{        // 请求三        [CommodityViewModel getPriceTransformForIntegral:nil onSuccess:^(id data) {            NSLog(@"duihuan22");            dispatch_semaphore_signal(semaphore);        } onFailure:^(NSError *error) {                    }];    });    dispatch_group_notify(group, queue, ^{        // 三个请求对应三次信号等待        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);        //在这里 进行请求后的方法，回到主线程        dispatch_async(dispatch_get_main_queue(), ^{            //更新UI操作        });    });

第二种 通过请求数量计数

定义一个block

typedef void(^Complete)();

将block作为类的属性

@property (copy, nonatomic) Complete complete;

实现方式：

NSInteger requestCount = 0;    //第一个网络请求    [CommodityViewModel getPriceTransformForIntegral:nil onSuccess:^(id data) {        NSLog(@"duihuan11");        requestCount++;        if (self.complete) {            self.complete();        }    } onFailure:^(NSError *error) {    }];    //第二个网络请求    [CommodityViewModel getPriceTransformForIntegral:nil onSuccess:^(id data) {        NSLog(@"duihuan22");        requestCount++;        if (self.complete) {            self.complete();        }    } onFailure:^(NSError *error) {    }];    //第三个网络请求    [CommodityViewModel getPriceTransformForIntegral:nil onSuccess:^(id data) {        NSLog(@"duihuan33");        requestCount++;        if (self.complete) {            self.complete();        }    } onFailure:^(NSError *error) {    }];    self.complete = ^{            //请求网络的数量等于3表示三个网络请求已完成            if (requestCount == 3) {                //在这里 进行请求后的方法，回到主线程                dispatch_async(dispatch_get_main_queue(), ^{                    //更新UI操作                });            }        };