Tips to Loading image from a URL to UIImage object
Load image pointed by URL, for example, http://mycodetips.com/images/image0.jpg, using NSURL, NSURLRequest, and NSURLConnection
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NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest: [NSURLRequest requestWithURL: [NSURL URLWithString:@“http://mycodetips.com/images/image0.jpg”]] delegate:self]; Implement delegate methods of NSURLConnection - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error - (void)connectionDidFinishLoading:(NSURLConnection *)connection NSMutableData object can be used store data fragment whenever it is received self.imageData = [NSMutableData data]; … - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [self.imagedata appendData:data]; } Sample code - (void)startDownload { self.imageData = [NSMutableData data]; // alloc+init and start an NSURLConnection; release on completion/failure NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest: [NSURLRequest requestWithURL: [NSURL URLWithString:imageURLString]] delegate:self]; self.imageConnection = conn; [conn release]; } - (void)cancelDownload { [self.imageConnection cancel]; self.imageConnection = nil; self.imageData = nil; } #pragma mark - #pragma mark Download support (NSURLConnectionDelegate) - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { [self.activeDownload appendData:data]; }- ( void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { // Clear the activeDownload property to allow later attempts self.imageData = nil; // Release the connection now that it’s finished self.imageConnection = nil; }- ( void)connectionDidFinishLoading:(NSURLConnection *)connection { // Set appIcon and clear temporary data/image UIImage *image = [[UIImage alloc] initWithData:self.imageData]; // Now we have loaded image in ‘image’ // DO WHATEVER WE WAN WITH ‘image’ // call our delegate and tell it that our icon is ready for display [delegate appImageDidLoad: image]; [image autorelease]; // clean-up self.imageData = nil; // Release the connection now that it’s finished self.imageConnection = nil; } |
