I have heavy code - loading images asynchronously. I am using Grand Central Dispatch, but Activity Indicator does not working. Help me find the error, please
func loadImage() {
if let imageUrl = NSURL(string: "http://\($url)/1.jpg") {
let imageRequest: NSURLRequest = NSURLRequest(URL: imageUrl)
let queue: NSOperationQueue = NSOperationQueue.mainQueue()
NSURLConnection.sendAsynchronousRequest(imageRequest, queue: queue, completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
if data != nil {
self.image = UIImage(data: data)!
self.productImageView.image = self.image
}
})
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.imageActivityIndicator.startAnimating()
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> Void in
self.loadImage()
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.imageActivityIndicator.stopAnimating()
})
});
}
it's happening because you are using the imageActivityIndicator in viewDidLoad and the views haven't been added to the main view yet, so if your code would work if you moved it to viewWillAppear function.
Plus you have to hide it when the image finished loading, so this makes your code like this:
func loadImage() {
if let imageUrl = NSURL(string: "http://skidon.info/1.jpg") {
let imageRequest: NSURLRequest = NSURLRequest(URL: imageUrl)
let queue: NSOperationQueue = NSOperationQueue.mainQueue()
NSURLConnection.sendAsynchronousRequest(imageRequest, queue: queue, completionHandler:{ (response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in
if data != nil {
self.image = UIImage(data: data)!
self.productImageView.image = self.image
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.imageActivityIndicator.stopAnimating()
self.imageActivityIndicator.hidden = true
})
}
})
}
}
override func viewWillAppear() {
super.viewWillAppear()
self.imageActivityIndicator.startAnimating()
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> Void in
self.loadImage()
});
}