NSURLConnection Delegate Returns Null

问题

I have followed a handful of examples on NSURLConnection, see latest below, but yet I keep getting null on the returned FinishLoading. I checked didReceiveResponse and its getting the data. What am I not doing right here?

EDITED: Now works as expected.

    #pragma mark NSURLConnection Delegate Methods

    - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
        _dataDictionary = [NSMutableDictionary new];
        _theReceivedData = [NSMutableData new];

        [_theReceivedData setLength:0];
        // add object
        [_dataDictionary setObject:_theReceivedData forKey:[connection description]];
    }

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

        NSMutableData *imageData = _dataDictionary[ [connection description] ];
        [imageData appendData:data];
        if([connection description]!=nil && imageData!=nil)
        {
            [_dataDictionary setObject:imageData forKey:[connection description]];
        }
    }

    - (NSCachedURLResponse *)connection:(NSURLConnection *)connection
                      willCacheResponse:(NSCachedURLResponse*)cachedResponse {
        // Return nil to indicate not necessary to store a cached response for this connection
        return nil;
    }

    - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
        // The request is complete and data has been received
        // You can parse the stuff in your instance variable now

        NSData *imageData = _dataDictionary[ [connection description] ];

if(imageData!=nil)
    {
        NSLog(@"%@",imageData);

回答1:

Take NSMutableData *theReceivedData out. Make it a class variable. Your problem is theReceivedData is being deallocated in every method. You are creating a new object in every method. Retain the old one.

NSMutableData *_theReceivedData;

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
            _theReceivedData = [NSMutableData new];
            [_theReceivedData setLength:0];
        }

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

        - (NSCachedURLResponse *)connection:(NSURLConnection *)connection
                          willCacheResponse:(NSCachedURLResponse*)cachedResponse {
            // Return nil to indicate not necessary to store a cached response for this connection
            return nil;
        }

        // LOOK AT THIS http://stackoverflow.com/questions/1064920/iphone-corrupt-jpeg-data-for-image-received-over-http

        - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
            NSLog(@"%@",_theReceivedData);

来源：https://stackoverflow.com/questions/30667340/nsurlconnection-delegate-returns-null

标签

objective-c

nsurlconnection