UIImageView and UIImage. Load Image From Remote URL.

In this Swift code example, you will learn how to create UIImageView programmatically and how to load an image from a remote URL.

  • Create UIImageView and UIImage programmatically,
  • Load image data from a remote URL,
  • Learn how to use dispatch_get_global_queue to start a background thread,
  • Learn how to use dispatch_get_main_queue to update UI when the background thread completes,
  • Add UIImageView as a subview to the main view,
  • Position UIImageView at the center of UIView.
import UIKit

class ViewController: UIViewController {
 override func viewDidLoad() {
     super.viewDidLoad()
 }
 
 override func viewWillAppear(_ animated: Bool) {
     super.viewWillAppear(animated)
     
     let imageUrlString = "http://swiftdeveloperblog.com/wp-content/uploads/2015/07/1.jpeg"
     let imageUrl:URL = URL(string: imageUrlString)!
     
     // Start background thread so that image loading does not make app unresponsive
      DispatchQueue.global(qos: .userInitiated).async {
         
         let imageData:NSData = NSData(contentsOf: imageUrl)!
         let imageView = UIImageView(frame: CGRect(x:0, y:0, width:200, height:200))
         imageView.center = self.view.center
         
         // When from background thread, UI needs to be updated on main_queue
        DispatchQueue.main.async {
             let image = UIImage(data: imageData as Data)
             imageView.image = image
            imageView.contentMode = UIView.ContentMode.scaleAspectFit
             self.view.addSubview(imageView)
         }
     }
 }
 
 override func didReceiveMemoryWarning() {
     super.didReceiveMemoryWarning()
     // Dispose of any resources that can be recreated.
 }
 
}

For more Swift code examples and tutorials, please check the Swift Code Examples page on this website.


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