UICollectionview委托和数据源未开始调用

Question

我试图以编程方式创建UICollectionview，

但由于某种原因，委托方法不会被调用。 我可以在视图调试器中看到委托和数据源是nil 可能是什么问题？ 感谢

mvn install

然后我从ViewController实例化 class MyClass: NSObject, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout { var contentView : UIView var collectionView : UICollectionView var images = [UIImage]() init(contentView : UIView, images : [UIImage]) { self.contentView = contentView self.images = images let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout() layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0) layout.itemSize = CGSize(width: contentView.frame.width, height: 700) layout.scrollDirection = .horizontal let cv = UICollectionView(frame: contentView.frame, collectionViewLayout: layout) cv.backgroundColor = .clear let nib = UINib(nibName: "MyCell", bundle: .main) cv.register(nib, forCellWithReuseIdentifier: "MyCell") self.collectionView = cv super.init() self.collectionView.delegate = self self.collectionView.dataSource = self contentView.addSubview(cv) } } ：

MyClass

Answer 1

在视图控制器代码中：

class SecondViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let images : [UIImage] = [...]
        let cv = MyClass(contentView: self.view, images: images)

        cv.startAnimation()

    }
} 

一旦程序执行离开viewDidLoad()，cv就不再存在。

您希望保留该对象，因此它可以充当委托和数据源：

class SecondViewController: UIViewController {

    var cv: MyClass?

    override func viewDidLoad() {
        super.viewDidLoad()

        let images : [UIImage] = [...]

        cv = MyClass(contentView: self.view, images: images)

        cv.startAnimation()

    }
}