Swift

Question

我的 ViewControllers 有问题。有谁知道为什么该代码不起作用？ print 函数工作...

A 到 B

    @IBAction func editButtonTapped(_ sender: Any) {
    let imageCollectionView = self.storyboard?.instantiateViewController(withIdentifier: "ImageCollectionVC") as! ImageCollectionViewController
    imageCollectionView.delegate = self
    self.navigationController?.pushViewController(imageCollectionView, animated: true)
    print("editButtonTapped")
}



}

    extension ExampleViewController: ClassBDelegate {
            func childVCDidComplete( with image: UIImage?) {
                self.pickedImage = image!
            }
    }

B 到 A

 protocol ClassBDelegate {
    func childVCDidComplete(with image: UIImage?)
}

class ImageCollectionViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout{

    @IBOutlet weak var imageCollectionView: UICollectionView!

    var delegate: ClassBDelegate?
var tappedImage = UIImage()

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
   tappedImage = images[indexPath.row]
   delegate?.childVCDidComplete(with: tappedImage)
   navigationController?.popViewController(animated: true)
}

这是我的完整项目：https://github.com/chriskonnerth/Wishlist

ViewController A 在我的例子中是 ExampleViewController 和 B 是 ImageCollectionViewController

更新

这是我的故事板：

ImageViewController是右边的，ExampleViewController是左边的

Answer 1

检查下面代码行中的 navigationController 实例：

self.navigationController?.pushViewController(imageCollectionView, animated: true)

如果 self.navigationController 为 nil，那么您可能没有在 ExampleViewController.

中嵌入导航控制器

然后您需要将您的第一个控制器与导航控制器一起嵌入。

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