Question

我有一个小应用程序，可以在壁纸库中显示图像。当用户选择图像时，他们可以将图像设置为MainViewController或返回图像库以设置不同的图像。

我的问题是：

如何在DetailsViewController的同时将图像从MainViewController发送到DetailsViewController。我不希望用户转到MainViewController。

这有什么意义吗？我已经在这几天了，无法理解如何去做。

import UIKit

class DetailViewController: UIViewController {


    @IBOutlet weak var categoryImageView: UIImageView!

    var image: UIImage!

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        self.navigationController?.navigationBar.setBackgroundImage(UIImage(),for: .default)
        self.navigationController?.navigationBar.shadowImage = UIImage()
        self.navigationController?.navigationBar.isTranslucent = true


    }


    override func viewDidLoad() {
        super.viewDidLoad()

        categoryImageView.image = image
        categoryImageView.contentMode = .scaleAspectFill

    }

}

Answer 1

您可以使用委托。更多信息The Swift Programming Language. Protocols

在DetailController中：

import UIKit

//define protocol
protocol DetailViewControllerDelegate {
    func didSelectImage(_ image: UIImage)
}

class DetailViewController: UIViewController {

    @IBOutlet weak var categoryImageView: UIImageView!

    var image: UIImage!

    //delegate var
    var delegate: DetailViewControllerDelegate?

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        self.navigationController?.navigationBar.setBackgroundImage(UIImage(),for: .default)
        self.navigationController?.navigationBar.shadowImage = UIImage()
        self.navigationController?.navigationBar.isTranslucent = true


    }


    override func viewDidLoad() {
        super.viewDidLoad()

        categoryImageView.image = image
        categoryImageView.contentMode = .scaleAspectFill

    }

    //the function that is called when you select an image in detail Controller
    //or you can use collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) instead
    func setImageToTheMain(_ image: UIImage) {

        delegate?.didSelectImage(image)
    }

}

在MainViewController中：

选项1）如果您正在使用segues

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "your segue to the detail identifier" {

        let destinationController = segue.destination as? DetailViewController
        //Set MainViewController as a delegate for DetailViewController
        //So it will receive data from DetalVC
        destinationController.delegate = self
    }
}

选项2）如果您正在使用演示文稿

func goToDetail() {

    let storyboard = UIStoryboard(name: "Detail storyboard name or Main", bundle: nil)

    guard let detailController = storyboard.instantiateViewController(withIdentifier: "Your Detail controller identifier") as? DetailViewController else {
        return
    }

    detailController.delegate = self

    self.present(detailController, animated: true, completion: nil)
}

当您的Master设置为委托时，您需要调用在协议中创建的方法：

extension MainViewController: DetailViewControllerDelegate{

    func didSelectImage(_ image: UIImage) {

        //set image to the Master Controller outlet here
        //something like this:
        yourImageView.image = image
    }
}

将图像发送到新视图控制器

1 个答案: