Question

我尝试使用UIImagePickerController来显示从照片库中挑选的图像，但是当我选择图像时，没有任何反应。

我所做的一切都来自Apple's Swift tutorial，所以代码不应该是错误的，我想。它既不在模拟器中也不在真实设备上工作。我已经尝试了谷歌搜索时发现的所有建议。我的代码：

import UIKit

class ViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

//MARK: Properties
@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var mealNameLabel: UILabel!
@IBOutlet weak var photoImageView: UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()
    nameTextField.delegate = self
}

//MARK: Actions

@IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) {

    // Hide the keyboard.
    nameTextField.resignFirstResponder()

    // UIImagePickerController is a view controller that lets a user pick media from their photo library.
    let imagePickerController = UIImagePickerController()

    // Only allow photos to be picked, not taken.
    imagePickerController.sourceType = .photoLibrary

    // Make sure ViewController is notified when the user picks an image.
    imagePickerController.delegate = self
    present(imagePickerController, animated: true, completion: nil)

    func imagePickerControllerDidCancel(picker: UIImagePickerController) {
        // Dismiss the picker if the user canceled.
        dismiss(animated: true, completion: nil)
    }

    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

        // The info dictionary may contain multiple representations of the image. You want to use the original.
        guard let selectedImage = info[UIImagePickerControllerOriginalImage] as? UIImage else {
            fatalError("Expected a dictionary containing an image, but was provided the following: \(info)")
        }

        // Set photoImageView to display the selected image.
        photoImageView.image = selectedImage

        // Dismiss the picker.
        dismiss(animated: true, completion: nil)
    }
}

@IBAction func setDefaultLabelText(sender: UIButton) {
    mealNameLabel.text = "Default Text"
}

//MARK: UITextFieldDelegate

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    return true
}

func textFieldDidEndEditing(_ textField: UITextField) {
    mealNameLabel.text = textField.text
}
}

如有必要，我可以提供更多信息。提前谢谢。

Answer 1

您的委托方法位于按钮操作范围内。

您必须在UIImagePickerControllerDelegate操作范围之外编写selectImageFromPhotoLibrary方法并使用正确的签名进行编写。

就像那样：

@IBAction func selectImageFromPhotoLibrary(sender: UITapGestureRecognizer) {

    // Hide the keyboard.
    nameTextField.resignFirstResponder()

    // UIImagePickerController is a view controller that lets a user pick media from their photo library.
    let imagePickerController = UIImagePickerController()

    // Only allow photos to be picked, not taken.
    imagePickerController.sourceType = .photoLibrary

    // Make sure ViewController is notified when the user picks an image.
    imagePickerController.delegate = self
    present(imagePickerController, animated: true, completion: nil)


    }
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
            // Dismiss the picker if the user canceled.
            dismiss(animated: true, completion: nil)
        }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

        // The info dictionary may contain multiple representations of the image. You want to use the original.
        guard let selectedImage = info[UIImagePickerControllerOriginalImage] as? UIImage else {
            fatalError("Expected a dictionary containing an image, but was provided the following: \(info)")
        }

        // Set photoImageView to display the selected image.
        photoImageView.image = selectedImage

        // Dismiss the picker.
        dismiss(animated: true, completion: nil)
    }

从iOS PhotoLibrary中选择的图像不会在UIImageView中显示

1 个答案: