iOS图像分辨率问题

Question

In My project I am using image view which downloads image from server. It is working fine on iOS 4 but it is not showing on iOS 5.

Is there any minimum resolution needs to be take care while using iOS 5. One of image which comes from server is of 72 dpi resolution which works on iOS 4 but not on iOS 5.

I have written category to image view which will download code from image URL Here is code snippet:

- (void) setImageFromServer:(NSString *) imageURL 
{
    if (imageURL!=nil) 
    {
        ImageDownloader *imageDownloader = [[[ImageDownloader alloc] init] autorelease];
        imageDownloader.requester = self;
        [imageDownloader startDownload:imageURL]; 
    }
}


- (void) didDownloadImageData:(NSData *) data forImageURL:(NSString *) imageURL 
{
    [self setImage:[UIImage imageWithData:data]];
}

In downloader file :

- (void) startDownload:(NSString *)MyimageURL {

    self.imageData = [NSMutableData data];
    self.currentImageURL = MyimageURL;

    self.downloadConnection = [NSURLConnection connectionWithRequest: [NSURLRequest requestWithURL:[NSURL URLWithString:self.currentImageURL]]
                                                            delegate: self];
    [self.downloadConnection start];
}



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

- (void) connectionDidFinishLoading:(NSURLConnection *)connection {
    [self.requester didDownloadImageData:self.imageData forImageURL:self.currentImageURL];
    isRewardTagImageAvailable = YES;
    [connection release];
    connection = nil;
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{

}

Answer 1

I am not sure if this is a problem, but usually when I am writing a NSURLRequest I first initialize things as follows and the insert the request into a NSURLConnection. Sort of like this. Also note that once you initWithRequst in a NSURLConnection, you do not have to tell that connection to start, it will automatically.

NSURLRequest *tempReq = [[NSURLRequest alloc] initWithURL:someURL cachePolicy:NSURLRequestReloadIgnoringCacheData  timeoutInterval:10.0];
NSURLConnection *tempCon = [[NSURLConnection alloc] initWithRequest:tempReq delegate:self];

I mean it should not matter, but give that a shot because looking at your, code it looks fine.

I would recommend adding the didFailWithError method:

-(void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;

To your files as well because maybe your connection is failing for some reason as well.

Answer 2

Is your connection synchronous or async ?

If async, you shouldn't autorelease your ImageDownloader, because there are some chance that it would be released for the connectionDidFinishLoading message.

Try to alloc your ImageDownloader normally, then release it when it finishes the download (both in connectionDidFinishLoading and didFailWithError )