This code example demonstrates how to:

• Create and preset UIImagePickerController programmatically
• Trigger UIImagePickerController with a button click
• Display image that user selected with UIImagePickerController
• Create and position UIImage programmatically
• Use ScaleAspectFit to make the selected image to fit into the UIImageView dimensions

import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate  {
    
    var myImageView: UIImageView!
    var showImagePicketButton: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        setupImagePickerButton()
        
        setupImageView()
        
    }
    
    func setupImagePickerButton()
    {
        let button = UIButton(type: UIButtonType.system) as UIButton
        
        let xPostion:CGFloat = 50
        let yPostion:CGFloat = 100
        let buttonWidth:CGFloat = 150
        let buttonHeight:CGFloat = 45
        
        button.frame = CGRect(x: xPostion, y: yPostion, width: buttonWidth, height: buttonHeight)
        
        button.backgroundColor = UIColor.lightGray
        button.setTitle("Tap me", for: UIControlState.normal)
        button.tintColor = UIColor.black
        button.addTarget(self, action: #selector(ViewController.displayImagePickerButtonTapped(_:)), for: .touchUpInside)
        self.view.addSubview(button)
    }
    
    func setupImageView()
    {
        myImageView = UIImageView()
        
        let xPostion:CGFloat = 50
        let yPostion:CGFloat = 200
        let buttonWidth:CGFloat = 200
        let buttonHeight:CGFloat = 200
        
        myImageView.frame = CGRect(x: xPostion, y: yPostion, width: buttonWidth, height: buttonHeight)
        
        self.view.addSubview(myImageView)
    }
    
    func displayImagePickerButtonTapped(_ sender:UIButton!) {
        
        let myPickerController = UIImagePickerController()
        myPickerController.delegate = self;
        myPickerController.sourceType = UIImagePickerControllerSourceType.photoLibrary
        
        self.present(myPickerController, animated: true, completion: nil)
        
    }
    
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
    {
        myImageView.image = info[UIImagePickerControllerOriginalImage] as? UIImage
        myImageView.backgroundColor = UIColor.clear
        myImageView.contentMode = UIViewContentMode.scaleAspectFit
        self.dismiss(animated: true, completion: nil)
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    
}

Watch this video tutorial to learn how to use UIImagePickerController to select an image from a photo library and upload image to a server side. This video tutorial also demonstrates how to display a progress bar while image is being uploaded.

Image Upload with Progress Bar example in Swift

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Unit Testing Swift Mobile App

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