从表面上看,我认为这必须是一个代表问题,但在要求代表后,正确的一个被退回.
我创建了一个ImagePicker类来处理所有UIImagePickerController的东西.在需要调用委托方法之前,每件事都有效.在我选择照片后,imagePicker会解散,但是didFinishPickingMediawithInfo方法永远不会被调用.请帮忙！谢谢 ：)
func selectPhoto() {
imagePicker.delegate = self //Delegate gets set here
let photoAsk = UIAlertController.init( //Ask user if they want to take picture or choose one
title: "Edit Profile Picture",message: nil,preferredStyle: .alert)
let cameraAction = UIAlertAction.init(
title: "Take Photo",style: .default) { (UIAlertAction) in
if (UIImagePickerController.isSourceTypeAvailable(.camera)) {
self.imagePicker.sourceType = .camera
UIApplication.topViewController()!.present(self.imagePicker,animated: true,completion:nil)
} else {
print("Cannot access camera in simulator.")
return
}
}
let photoLibraryAction = UIAlertAction.init(
title: "Photo Library",style: .default) { (UIAlertAction) in
self.imagePicker.sourceType = .photoLibrary
UIApplication.topViewController()!.present(self.imagePicker,completion:nil)
print("UIImagePickerDelegate: \(self.imagePicker.delegate.debugDescription)") // <--THIS PRINTS OUT "AppName.ImagePicker: 0x145d7bdf0>",and the class name is ImagePicker
}
let cancelAction = UIAlertAction.init(
title: "Cancel",style: .cancel) { (UIAlertAction) in return }
photoAsk.addAction(cameraAction)
photoAsk.addAction(photoLibraryAction)
photoAsk.addAction(cancelAction)
imagePicker.mediaTypes = [kUTTypeImage as String]
UIApplication.topViewController()?.present(photoAsk,completion: nil)
}
}
永远不会被称为：
func imagePickerController(_ picker: UIImagePickerController,didFinishPickingMediawithInfo info: [String : Any]) {
print("Image picked.") //NEVER PRINTS
}
解决方法
细节
Xcode 9.2,Swift 4
解
extension BaseViewController: UIImagePickerControllerDelegate,UINavigationControllerDelegate {
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
dismiss(animated: true,completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController,didFinishPickingMediawithInfo info: [String : Any]) {
NSLog("\(info)")
let image = info[UIImagePickerControllerOriginalImage] as? UIImage
imagePickerController(picker,pickedImage: image)
}
@objc func imagePickerController(_ picker: UIImagePickerController,pickedImage: UIImage?) {
}
}
完整样本
BaseViewController.swift
import UIKit
class BaseViewController: UIViewController {
let imagePicker = UIImagePickerController()
override func viewDidLoad() {
super.viewDidLoad()
imagePicker.delegate = self
}
}
extension BaseViewController: UIImagePickerControllerDelegate,pickedImage: UIImage?) {
}
}
ViewController.swift
import UIKit
class ViewController: BaseViewController {
weak var imageView: UIImageView?
override func viewDidLoad() {
super.viewDidLoad()
let stackView = UIStackView(frame: .zero)
stackView.axis = .vertical
stackView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(stackView)
stackView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
stackView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFit
imageView.translatesAutoresizingMaskIntoConstraints = false
stackView.addArrangedSubview(imageView)
imageView.widthAnchor.constraint(equalToConstant: 200).isActive = true
imageView.heightAnchor.constraint(equalToConstant: 200).isActive = true
self.imageView = imageView
let button = UIButton(frame: .zero)
button.setTitle("Button",for: .normal)
button.setTitleColor(.blue,for: .normal)
button.addTarget(self,action: #selector(showImages),for: .touchUpInside)
stackView.addArrangedSubview(button)
}
@IBAction func showImages(_ sender: AnyObject) {
imagePicker.allowsEditing = false
imagePicker.sourceType = .photoLibrary
present(imagePicker,completion: nil)
}
override func imagePickerController(_ picker: UIImagePickerController,pickedImage: UIImage?) {
if let image = pickedImage {
imageView?.image = image
dismiss(animated: true,completion: nil)
}
}
}