在 UIProgressView 上添加 NSURLConnection 加载过程

Question

我创建了一个UIProgressView。但我使用NSTimer 到UIProgressView's 进程。现在我需要在加载 URL 时集成UIProgressView 进程。 UIProgressView's 的大小将取决于 NSURLConnection's 数据。

我用下面的代码NSURLConnection。

-(void)load {
    NSURL *myURL = [NSURL URLWithString:@"http://feeds.epicurious.com/newrecipes"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL
                                                           cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                                       timeoutInterval:60];

    [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    responseData = [[NSMutableData alloc] init];
}


-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [responseData appendData:data];
}

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    [connection release];

    UIAlertView *alert = [[UIAlertView alloc] init];
    [alert setTitle:@"Warning"];
    [alert setMessage:@"Network Connection Failed?"];
    [alert setDelegate:self];
    [alert addButtonWithTitle:@"Yes"];

    [alert show];
    [alert release];

    NSLog(@"Error");
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection 
{
    responsetext = [[[NSString alloc] initWithData:responseData encoding: NSASCIIStringEncoding] autorelease];
}

Answer 1

在您的 didReceiveResponse 函数中，您可以获得总文件大小，如下所示： _totalFileSize = response.expectedContentLength;.

然后，在您的 didReceiveData 函数中，您可以将接收到的总字节数计数器相加： _receivedDataBytes += [data length];

现在，为了将进度条设置为正确的大小，您只需执行以下操作： MyProgressBar.progress = _receivedDataBytes / (float)_totalFileSize

（在 didReceiveData 函数或代码中的其他位置）

不要忘记将保存字节数的变量添加到您的类中！

我希望这会有所帮助..

编辑：以下是您如何实现委托以更新进度视图

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    _totalFileSize = response.expectedContentLength;
    responseData = [[NSMutableData alloc] init];
}


-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
   _receivedDataBytes += [data length];
   MyProgressBar.progress = _receivedDataBytes / (float)_totalFileSize;
   [responseData appendData:data];
 }