UICollectionView宽度未以编程方式展开

Question

在我的尝试中，我可以减少左侧的集合视图的宽度，但我无法放大它。

我尝试了很多方法，但无法达到结果。

我想按右上方的按钮左右滑动。代码如下：

class ViewController: UIViewController {

    @IBOutlet weak var listView: UIView!
    @IBOutlet weak var collectionView: UICollectionView!
    @IBOutlet weak var collectionViewConstraintWidth: NSLayoutConstraint!
    var IsOpenedList:Bool = false
    var collectionViewWidth:CGFloat = 0

    var collectionData = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        collectionView.delegate = self
        collectionView.dataSource = self

        let button1 = UIBarButtonItem(title: "Sepet", style: .plain, target: self, action: #selector(ViewController.openList))
        self.navigationItem.rightBarButtonItem  = button1

        let layout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
        collectionViewWidth = layout.itemSize.width
//        let width = collectionView.bounds.width / 2
//        layout.itemSize = CGSize(width: width, height: 100)
//        layout.estimatedItemSize = CGSize(width: width, height: 100)
//        layout.minimumInteritemSpacing = CGFloat(2)
    }

    @objc func openList(){
        collectionView.widthAnchor.constraint(equalToConstant: collectionViewWidth/3).isActive = false
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        listView.translatesAutoresizingMaskIntoConstraints = false

        let layout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
        if IsOpenedList {
//            collectionView.widthAnchor.constraint(equalToConstant: 600).isActive = true
            // Add Constraint
            let constraintWidth = NSLayoutConstraint(
                item: collectionView,
                attribute: .width,
                relatedBy: .lessThanOrEqual,
                toItem: nil,
                attribute: .notAnAttribute,
                multiplier: 1.0,
                constant: 320.0
            )
            collectionView.addConstraint(constraintWidth)
            let a = collectionView.widthAnchor.constraint(lessThanOrEqualToConstant: 320.0)
            a.priority = UILayoutPriority(rawValue: 750)
            a.isActive = true
//            listView.leadingAnchor.constraint(equalTo: self.view.layoutMarginsGuide.leadingAnchor, constant: collectionViewWidth/3).isActive = true
//            listView.leadingAnchor.constraint(equalTo: self.view.layoutMarginsGuide.leadingAnchor, constant: collectionViewWidth).isActive = true
            collectionView.widthAnchor.constraint(equalToConstant: collectionViewWidth).isActive = true
//            collectionView.trailingAnchor.constraint(equalTo: listView.layoutMarginsGuide.leadingAnchor, constant: collectionViewWidth).isActive = true
////            listView.isHidden = true
////            listView.leadingAnchor.constraint(equalTo: collectionView.layoutMarginsGuide.trailingAnchor, constant: 8).isActive = true
//            collectionViewConstraintWidth.constant = collectionViewWidth
//            collectionViewConstraintWidth.isActive = true
////            collectionView.reloadData()
        }else{
//            listView.isHidden = false
            listView.leadingAnchor.constraint(equalTo: self.view.layoutMarginsGuide.leadingAnchor, constant: collectionViewWidth/3).isActive = true



//            collectionView.reloadData()
        }
        UIView.animate(withDuration: 0.5) {
            self.view.layoutIfNeeded()
        }
        IsOpenedList = !IsOpenedList
    }
}

extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return collectionData.count
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let padding: CGFloat =  4
        let collectionViewSize = collectionView.frame.size.width - padding

        return CGSize(width: collectionViewSize/3, height: collectionViewSize/3)
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath)

        if let label = cell.viewWithTag(100) as? UILabel {
            label.text = collectionData[indexPath.row]
        }
        return cell
    }


}

预览：第二次按下按钮时，该按钮不会执行任何操作