ios - 来自 url 的按钮的图像 - 等待 10 秒后返回失败。主运行循环模式 : kCFRunLoopDefaultMode

Question

我有一个包含 json 格式的 URL。

{
      "name":"RAI Radiodue",
      "cat":"Adult Contemporary",
      "img":"http://www.rai.it/dl/portaleRadio/images/ico_radio2.jpg",
      "url":"http://www.listenlive.eu/rai2.m3u"
   },
   {
      "name":"RAI Radiotre",
      "cat":"Classical/Culture",
      "img":"http://www.rai.it/dl/portaleRadio/images/ico_radio3.jpg",
      "url":"http://www.listenlive.eu/rai3.m3u"
   }........etc

我正在尝试使用以下代码显示许多单选按钮:

    for (int i = 0;  i<[namesArray count]; i++) {

        NSURL *url = [NSURL URLWithString: [pictureUrl objectAtIndex:i]];

        NSData *data = [NSData dataWithContentsOfURL:url];
        UIImageView *subview = [[UIImageView alloc] init];
        [subview setImage:[UIImage imageWithData:data]];



        UIButton *bt = [UIButton buttonWithType:UIButtonTypeCustom];

        int xxx = i%3;
        int yyy = i/3.0f;
        [bt setFrame:CGRectMake(35+95*xxx, 15+100*yyy, 60, 60)];
        [bt setBackgroundImage:subview forState:UIControlStateNormal];

        bt.tag = 200+i;
        bt.selected = NO;
        [bt.layer setMasksToBounds:NO];
        [bt.layer setShadowColor:[UIColor blackColor].CGColor];
        [bt.layer setShadowOpacity:0.8f];
        [bt.layer setShadowOffset:CGSizeMake(1.0f, 1.0f)];
        [bt addTarget:self action:@selector(Play:) forControlEvents:UIControlEventTouchUpInside];
        [mainscroll addSubview:bt];
}

并为每个按钮添加来自 pictureUrl 的已填充图像，但是当我想转到此 View Controller 时，我在控制台中得到此输出:

2014-12-18 17:32:40.763 TV[3128:935103] NSURLConnection/CFURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9813)
2014-12-18 17:32:46.041 TV[3128:935134] void SendDelegateMessage(NSInvocation *): delegate (webView:decidePolicyForNavigationAction:request:frame:decisionListener:) failed to return after waiting 10 seconds. main run loop mode: kCFRunLoopDefaultMode.

我该怎么办 ？

Answer 1

NSData *data = [NSData dataWithContentsOfURL:url]; 

此行阻塞主线程，主线程在运行此行之前会等待数据下载:

UIImageView *subview = [[UIImageView alloc] init];
[subview setImage:[UIImage imageWithData:data]];

您必须在其他线程中运行下载数据并在下载数据时设置您的图像。