UIActivityIndicatorView when loading image from online? - objective-c

Question

I have a simple script that displays in a UIImageView from the internet.
Is there a way to display a UIActivityIndicatorView or something of that sort to show the user that it's loading?
Here's my minimal code:
NSString *imagePath = [NSString stringWithFormat:#"urlofimagehere.jpg"];
NSData *mydata = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:imagePath]];
UIImage *myimage = [[UIImage alloc] initWithData:mydata];
[imageView setImage:myimage];
[myimage release];
Thanks!
Coulton
EDIT: CODE REMOVED

Answer 1

-[NSData initWithContentsOfURL:]
is a synchronous method. This means it will block until the data is loaded over the network. If you want to be able to keep your UI responsive, you'll want to use an asynchronous approach. For more info, read this: http://akosma.com/2010/05/28/initwithcontentsofurl-methods-considered-harmful/
I'd recommend using NSURLRequest with an NSURLRequestDelegate to receive callbacks when the data is finished loading. Here's an example:
- (void)loadImageAtURL(NSString *)urlString {
[myUIActivityIndicatorView startAnimating];
// SHOW NETWORK INDICATOR
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
// SET UP THE REQUEST
NSURL *url = [[NSURL alloc] initWithString:urlString];
NSURLRequest *request = [[[NSURLRequest alloc] initWithURL:url] autorelease];
// SET UP THE CONNECTION
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
mutData = [[[NSMutableData alloc] init] retain];
}
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error {
// Handle error
}
- (void)connection:(NSURLConnection *)connection
didReceiveData:(NSData *)data {
[mutData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)aConnection {
// ONCE LOADED HIDE NETWORK INDICATOR
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
// RELEASE THE CONNECTION
[connection release];
// CREATE NEW UIIMAGE FROM THE DATA
image = [[[UIImage alloc] initWithData:mutData] retain];
[mutData release];
// HIDE THE ACTIVITY INDICATOR
// Make sure hidesWhenStopped is set to YES on the activity indicator.
[myUIActivityIndicatorView stopAnimating];
[myUIImageView setImage:image];
[image release];
}
Hope this helps!