下载图像时的进度条

Question

如何添加用于下载大图片或任何文件的进度条？这是我的代码：

NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                             NSUserDomainMask, YES);

        NSString *docsPath = [paths objectAtIndex:0];
        NSString *downloadPath = [[[NSString alloc]initWithFormat:@"http://www.zzz.com/%@.jpg",chartFileName]autorelease];
        NSString *savePath = [[[NSString alloc]initWithFormat:@"%@/%@.jpg",docsPath, chartFileName]autorelease];
        NSURL *url = [[NSURL alloc]initWithString:downloadPath];
        NSData *downloadedChartData = [NSData dataWithContentsOfURL:url];
        [url release];
        [downloadedChartData writeToFile:savePath atomically:YES];

Answer 1

您可以在NSURLConnection调用中覆盖connection：didReceiveData :.请点击此处了解更多信息：

How to integrate NSURLConnection with UIProgressView?

Answer 2

在后台运行一个检查图像下载大小的选择器，并将其与所需大小进行比较。然后将进度条的％设置为已下载/必需。