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我有一个关于 NSURLConnection 的问题：我想下载一张图片：

NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];

（正确）调用的第一个代表是

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

在这被调用一次之后：

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

并立即：

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

到这里为止一切都是正确的，但是在再次触发 connectionDidFinishLoading 后，同一连接的 didReceiveData 委托，我通过以下方式识别连接：

NSString * connectionKey = [[[connection originalRequest] URL] absoluteString];

这可能吗？

更新，更多信息：

我的应用程序触发了许多同时连接，并且我将任何连接的信息存储在字典中，当调用委托时，我使用密钥检索连接信息： NSString * connectionKey = [[[connection originalRequest] URL] absoluteString]; 对于 99% 的连接，一切都很好，但对于一个（每次都一样！）连接我有这种行为

这里是完整的实现：

    - (void)downloadFileFromUrl:(NSURL *)url
                     inPath:(NSString *)completeFilePath
          dataReceivedBlock:(void (^)(long long byteDownloaded ,long long totalByte))dataReceivedBlock
                   endBlock:(void (^)(NSString * downloadPath, NSDictionary * responseHeaders))endBlock
                  failBlock:(void (^)(NSString * downloadPath, NSDictionary * responseHeaders, NSError * error))failBlock
{
    //save the connection infos       
NSMutableDictionary * requestData = [[NSMutableDictionary alloc] init];
if(dataReceivedBlock)
[requestData setObject:[dataReceivedBlock copy] forKey:@"dataReceivedBlock"];
if(endBlock)
[requestData setObject:[endBlock copy] forKey:@"endBlock"];
if(failBlock)
[requestData setObject:[failBlock copy] forKey:@"failBlock"];

        [requestData setObject:[NSNumber numberWithBool:YES] forKey:@"usingBlock"];
        [requestData setObject: completeFilePath forKey:@"downloadDestinationPath"];

    //delete the file if already on fs
    if([[NSFileManager defaultManager] fileExistsAtPath: completeFilePath])
        [[NSFileManager defaultManager] removeItemAtPath:completeFilePath error:nil];

    // Create the request.
    NSURLRequest * urlRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLCacheStorageAllowed timeoutInterval:TIME_OUT];
    NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
    if (!theConnection)
    {
        // Inform the user that the connection failed.
        failBlock(completeFilePath,nil,[NSError errorWithDomain:@"Connection fail" code:0 userInfo:nil]);
    }

    //add connection infos to the requests dictionary
    NSString * connectionKey = [[[theConnection originalRequest] URL] absoluteString];
    [self.requests setObject:requestData forKey:connectionKey];
}

这是一个委托示例：

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

NSString * connectionKey = [[[connection originalRequest] URL] absoluteString];
NSMutableDictionary * requestData = [self.requests objectForKey:connectionKey];
NSFileHandle *file = [requestData objectForKey:@"fileHandle"];
[file closeFile];

//se la richiesta usa o no block
BOOL usingBlock = [[requestData objectForKey:@"usingBlock"] boolValue];
if(usingBlock)
{
    __block void (^endBlock)(NSString * , NSDictionary *) = [requestData objectForKey:@"endBlock"];
    if(endBlock)
        endBlock([requestData objectForKey:@"downloadDestinationPath"],[requestData objectForKey:@"responseHeaders"]);
}
else
    [self.delegate downloadEnded:[requestData objectForKey:@"responseHeaders"]];


//elimino dati richiesta
[self.requests removeObjectForKey:[NSString stringWithFormat:@"%@",connectionKey]];

//Inibisco standby
[UIApplication sharedApplication].idleTimerDisabled = NO;
}
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2 回答 2

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不可能。它必须是不同的连接回调。

确保每个连接使用唯一的委托，或同一委托中的唯一交换机分支。

于 2013-02-21T11:04:18.803 回答
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显然解决方案非常简单 -_- 错误在连接密钥标识符中：

NSString * connectionKey = [[[connection originalRequest] URL] absoluteString];

我的假设是密钥是唯一的，但是如果我在同一个 url 为同一个文件进行 x 个并行下载，则假设是错误的；）

于 2013-02-25T12:09:40.103 回答