ios - 在 UIProgressView 上添加 NSURLConnection 加载过程

Question

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

我将以下代码用于 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，您可以添加总字节数接收计数器:_receivedDataBytes += [数据长度];

现在为了将进度条设置为正确的大小，您可以简单地执行以下操作:MyProgressBar.progress = _receivedDataBytes/(float)_totalFileSize

(在 didReceiveData 函数中或代码中的其他地方)

不要忘记将保存字节数的变量添加到您的类中!

希望对你有帮助

编辑:以下是您如何实现委托(delegate)以更新进度 View

-(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];
 }