iOS多图上传

iOS多图上传涉及到多线程问题,个人比较喜欢使用GCD操作,下边是最近写的一个多图上传代码,附带相关注释

 __block BOOL allSucc = YES;
    __block int m = 0;
    //创建线程队列上传图片
    self.photoDictArray = [NSMutableArray array];
    dispatch_queue_t uploadQueue = dispatch_queue_create("upload", DISPATCH_QUEUE_CONCURRENT);
    dispatch_group_t group = dispatch_group_create();
    dispatch_semaphore_t signal = dispatch_semaphore_create(3);//线程并发数3(保持3张图片同时上传)
    for (UIImage * image in self.dataImageArr) {
        dispatch_group_enter(group);
        dispatch_async(uploadQueue, ^{
            dispatch_semaphore_wait(signal, DISPATCH_TIME_FOREVER);
            m++;
            if (allSucc == NO) {
                dispatch_semaphore_signal(signal);
                dispatch_group_leave(group);
                NSLog(@"本次上传被取消");
            }else{
                [FileUploader uploadImageToQiniu:image finishAction:^(NSString *url, NSError *error) {
                    if (!error) {
                        //上传成功
                        [self.photoDictArray addObject:@{@"url":url, @"height":@(image.size.height), @"width":@(image.size.width)}];
                        dispatch_semaphore_signal(signal);
                        dispatch_group_leave(group);
                        NSLog(@"第%d次上传成功",m);
                    }else{
                        //上传失败
                        allSucc = NO;
                        dispatch_semaphore_signal(signal);
                        dispatch_group_leave(group);
                        NSLog(@"第%d次上传失败",m);
                    }
                }];
            }
        });
    }
    
    dispatch_group_notify(group, dispatch_get_main_queue(), ^{
        if (!allSucc) {
            //个别图片上传失败
            [TipsView showTips:@"图片上传失败,请重试"];
            return;
        }
        
//        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:self.photoDictArray options:NSJSONWritingPrettyPrinted error:nil];
//        NSString * imagesStr = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
        //全部上传成功
        [HttpClient postUrl:URL_Gossip_Publish dic:@{@"content":self.textView.text, @"images":self.photoDictArray} finish:^(NSURLSessionDataTask *task, id responseObj, NSError *error) {
            if (self.submitAction) {
                self.submitAction(error);
            }
            if (!error) {
                if (self.isHTMLPush) {
                    [TipsView showTips:@"发布成功!"];
                    [self.navigationController popViewControllerAnimated:YES];
                }else{
                    NativeViewController * controller = [[NativeViewController alloc]init];
                    controller.url = responseObj[@"data"][@"appUrl"];
                    [[AppDelegate rootNavController] pushViewController:controller animated:YES];
                    
                    NSMutableArray * controllerArr = [[NSMutableArray alloc]initWithArray:[AppDelegate rootNavController].viewControllers];
                    if ([controllerArr containsObject:self]) {
                        [controllerArr removeObject:self];
                    }
                    [AppDelegate rootNavController].viewControllers = [[NSArray alloc]initWithArray:controllerArr];
                }
            }
        }];
    });

 采用信号量和group来控制线程并发,所有图片上传完毕,通过dispatch_group_notify获取到上传结束的动作通知,然后进行下一步操作