How to allow user to pick the image with Swift?

If you just want let the user choose image with UIImagePickerController use this code:

import UIKitclass ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {    @IBOutlet var imageView: UIImageView!    @IBOutlet var chooseBuuton: UIButton!    var imagePicker = UIImagePickerController()    @IBAction func btnClicked() {        if UIImagePickerController.isSourceTypeAvailable(.savedPhotosAlbum){            print("Button capture")            imagePicker.delegate = self            imagePicker.sourceType = .savedPhotosAlbum            imagePicker.allowsEditing = false            present(imagePicker, animated: true, completion: nil)        }    }    func imagePickerController(picker: UIImagePickerController!, didFinishPickingImage image: UIImage!, editingInfo: NSDictionary!){        self.dismiss(animated: true, completion: { () -> Void in        })        imageView.image = image    }}

Complete copy-paste working image picker for swift 4 based on @user3182143 answer:

import Foundationimport UIKitclass ImagePickerManager: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {    var picker = UIImagePickerController();    var alert = UIAlertController(title: "Choose Image", message: nil, preferredStyle: .actionSheet)    var viewController: UIViewController?    var pickImageCallback : ((UIImage) -> ())?;        override init(){        super.init()        let cameraAction = UIAlertAction(title: "Camera", style: .default){            UIAlertAction in            self.openCamera()        }        let galleryAction = UIAlertAction(title: "Gallery", style: .default){            UIAlertAction in            self.openGallery()        }        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel){            UIAlertAction in        }        // Add the actions        picker.delegate = self        alert.addAction(cameraAction)        alert.addAction(galleryAction)        alert.addAction(cancelAction)    }    func pickImage(_ viewController: UIViewController, _ callback: @escaping ((UIImage) -> ())) {        pickImageCallback = callback;        self.viewController = viewController;        alert.popoverPresentationController?.sourceView = self.viewController!.view        viewController.present(alert, animated: true, completion: nil)    }    func openCamera(){        alert.dismiss(animated: true, completion: nil)        if(UIImagePickerController .isSourceTypeAvailable(.camera)){            picker.sourceType = .camera            self.viewController!.present(picker, animated: true, completion: nil)        } else {            let alertController: UIAlertController = {                let controller = UIAlertController(title: "Warning", message: "You don't have camera", preferredStyle: .alert)                let action = UIAlertAction(title: "OK", style: .default)                controller.addAction(action)                return controller            }()            viewController?.present(alertController, animated: true)        }    }    func openGallery(){        alert.dismiss(animated: true, completion: nil)        picker.sourceType = .photoLibrary        self.viewController!.present(picker, animated: true, completion: nil)    }        func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {        picker.dismiss(animated: true, completion: nil)    }    //for swift below 4.2    //func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {    //    picker.dismiss(animated: true, completion: nil)    //    let image = info[UIImagePickerControllerOriginalImage] as! UIImage    //    pickImageCallback?(image)    //}        // For Swift 4.2+    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {        picker.dismiss(animated: true, completion: nil)        guard let image = info[.originalImage] as? UIImage else {            fatalError("Expected a dictionary containing an image, but was provided the following: \(info)")        }        pickImageCallback?(image)    }    @objc func imagePickerController(_ picker: UIImagePickerController, pickedImage: UIImage?) {    }}

Call it from your viewcontroller like this:

    ImagePickerManager().pickImage(self){ image in        //here is the image    }

Also don't forget to include the following keys in your info.plist:

<key>NSCameraUsageDescription</key><string>This app requires access to the camera.</string><key>NSPhotoLibraryUsageDescription</key><string>This app requires access to the photo library.</string>

For Swift 3:

1. First, you need to add the following key in info.plist:

       <key>NSPhotoLibraryUsageDescription</key><string>This app requires access to the photo library.</string>

2. Your View controller needs to conform to the following protocols:UIImagePickerControllerDelegate, UINavigationControllerDelegate:

   class ImagePickerViewController:  UIViewController,UIImagePickerControllerDelegate, UINavigationControllerDelegate {}

3. You need to declare the UIImage you will be useing to bind the returned/selected image:

   @IBOutlet weak var myImageView: UIImageView!@IBoutlet weak var upLoadImageBtn:UIImage!let imagePicker = UIImagePickerController()

4. Set the pickerImage delegate to be your ViewController:

   imagePicker.delegate = self

5. For the upload button, you will need to link to the following image in order to fire the action and display the image picker:

   @IBAction func upLoadImageBtnPressed(_ sender: AnyObject) {    imagePicker.allowsEditing = false    imagePicker.sourceType = .photoLibrary    /*    The sourceType property wants a value of the enum named        UIImagePickerControllerSourceType, which gives 3 options:    UIImagePickerControllerSourceType.PhotoLibrary    UIImagePickerControllerSourceType.Camera    UIImagePickerControllerSourceType.SavedPhotosAlbum    */    present(imagePicker, animated: true, completion: nil)}

6. Your View controller needs to implement the delegate methods for the image picker delegates:

   // MARK: - ImagePicker Delegatefunc imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {    if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {        myImageView.contentMode = .scaleAspectFit        myImageView.image = pickedImage    }    /*    Swift Dictionary named “info”.      We have to unpack it from there with a key asking for what media information we want.    We just want the image, so that is what we ask for.  For reference, the available options are:    UIImagePickerControllerMediaType    UIImagePickerControllerOriginalImage    UIImagePickerControllerEditedImage    UIImagePickerControllerCropRect    UIImagePickerControllerMediaURL    UIImagePickerControllerReferenceURL    UIImagePickerControllerMediaMetadata    */    dismiss(animated: true, completion: nil)}func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {    dismiss(animated: true, completion:nil)}