Ios 嵌套集合视图单元格在方向更改时不调整大小

外部集合视图（在ViewController文件中）

• 占据整个屏幕的宽度和高度

• 单元格还占据屏幕的整个宽度和高度

• 集合视图布局是水平的。能够滑动到下一个单元格

• 细胞的背景是绿色的

嵌套集合视图（在CollectionViewCell文件中）

• 占据屏幕的整个宽度和高度

• 单元格占据屏幕的整个宽度。身高是100,

• 细胞紫背景

问题

我首先在Xcode中的模拟器上以纵向方向运行应用程序

当我将方向更改为横向并滑动所有屏幕时

一个屏幕上的紫色单元格不会占据整个屏幕。这个问题只发生在景观中

问题：总是有一个屏幕有这样的紫色单元格

假设所有单元格在方向图上的外观

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        
        window = UIWindow()
        window?.makeKeyAndVisible()
        
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        
        window?.rootViewController = ViewController(collectionViewLayout: layout)
        
        return true
        
    }
    
}

如果问题没有发生，请将方向更改回“纵向”，然后将其更改为“横向”。然后再次浏览所有单元格以查找问题

应用程序Delagate

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        
        window = UIWindow()
        window?.makeKeyAndVisible()
        
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        
        window?.rootViewController = ViewController(collectionViewLayout: layout)
        
        return true
        
    }
    
}

视图控制器

import UIKit

class ViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        collectionView?.register(CollectionViewCell.self, forCellWithReuseIdentifier: "cellid")
        collectionView?.isPagingEnabled = true
    }
    
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }
    
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellid", for: indexPath) as! CollectionViewCell
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: view.frame.width, height: view.frame.height)
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        collectionViewLayout.invalidateLayout()
    }
    
}

集合视图单元格（具有嵌套集合视图）

内部单元格（嵌套集合视图的单元格）

我在github上有这个项目

嘿，看看这个，看看是否有用

import UIKit

class InnerCell: UICollectionViewCell {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        backgroundColor = .purple
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
}

 override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    collectionViewLayout.invalidateLayout()
    // Also try reloading your collection view to calculate the new constraints
    DispatchQueue.main.async{
        collectionView.reloadData()
    }
}