如何使用ASINetWorkQueue下载实现

假设有这么个触发下载方法叫

- (IBAction)startDownLoad:(id)sender 

本地viewController有这么个instance variable : ASINetWorkQueue *netWorkQueue

可以从该实例的头文件中看到该queue属于一个NSOperationQueue

在触发方法实现如下代码

// lazy init 你的实例netWorkQueue
if (!networkQueue) {
        networkQueue = [[ASINetworkQueue alloc]init];
    }
// 使得每一次下载都是重新来过的
    [networkQueue reset];
    //UI监听器，设置用来监察整个过程的UI界面
    [networkQueue setDownloadProgressDelegate:wholeProgress];
//    [networkQueue setRequestDidFinishSelector:@selector(imageFetchComplete:)];
// 设置queue完成后需要实现的UI方法，根据头文件里面定义，这个UI方法需要一个ASIHTTPRequest 的参数
    networkQueue.requestDidFinishSelector = @selector(imageFetchComplete:);
    [networkQueue setRequestDidFailSelector:@selector(imageFetchFailed:)];
    networkQueue.showAccurateProgress = [self.accurateInfo isOn];
// 如果要实现SEL的方法则根据头文件定义需要把delegate定为self
    networkQueue.delegate = self;
    

//这里是给queque添加任务的。
    ASIHTTPRequest *request;
//定义request
    request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:@"http://allseeing-i.com/ASIHTTPRequest/tests/images/small-image.jpg"]];
//定义request的下载目标地址
    request.downloadDestinationPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"1.png"];
//定义request 下载的ui同步
    request.downloadProgressDelegate = self.imageView1Progress;
//纪录request信息
    request.userInfo = [NSDictionary dictionaryWithObject:@"request1" forKey:@"name"];
    [networkQueue addOperation:request];

- (void)imageFetchComplete:(ASIHTTPRequest *)request

{

UIImage *img = [UIImage imageWithContentsOfFile:[request downloadDestinationPath]];

}