Swift 更改按钮 position 不起作用

Question

我正在尝试更改 UIButton，但它不起作用。 我的代码是这样的。

@IBAction func addButtonTapped(_ sender: Any) {
    print(defaultAddButton.center)
    let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
    let width = self.view.bounds.width
    let height: CGFloat = 100
    let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
    self.view.addSubview(uiView)
    
    self.defaultAddButton.center.y += 200
}

SubCollectionView 是我的自定义视图。 上面的代码在没有 self.view.addSubview(uiView) 行的情况下工作。 我不明白为什么它不起作用。 先感谢您！

Answer 1

您可以尝试在视图中设置更改/框架

viewDidLayoutSubviews

Answer 2

您应该在此之后调用layoutIfNeeded() 。

@IBAction func addButtonTapped(_ sender: Any) {
        print(defaultAddButton.center)
        let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
        let width = self.view.bounds.width
        let height: CGFloat = 100
        let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
        self.view.addSubview(uiView)
        self.defaultAddButton.center.y += 200
        self.view.layoutIfNeeded()
    }

如果这不起作用。 请尝试在主队列中调用 UI 修改代码。

@IBAction func addButtonTapped(_ sender: Any) {
        print(defaultAddButton.center)
        DispatchQueue.main.async {
            let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
            let width = self.view.bounds.width
            let height: CGFloat = 100
            let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
            self.view.addSubview(uiView)
            self.defaultAddButton.center.y += 200
            self.view.layoutIfNeeded()
        }
    }

Answer 3

不完全理解你的问题，但可以建议你有问题 animation，用这行代码：

self.defaultAddButton.center.y += 200

上面的代码不起作用，因为您需要更新视图以立即更新其布局，使用此方法更新视图“ layoutIfNeeded() ”

代码示例：

class VC: UIViewController {
lazy var buttonAction: UIButton = {
        let view = UIButton()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.setTitle("Action", for: .normal)
        view.setTitleColor(#colorLiteral(red: 1, green: 1, blue: 1, alpha: 1), for: .normal)
        view.backgroundColor = .blue
        view.addTarget(self, action: #selector(action(_:)), for: .touchUpInside)
        return view
    }()
    
    @objc func action(_ sender: UIButton) {
        print("action")
        print(buttonAction.center)
        
        let buttonPos = CGPoint(x: buttonAction.frame.midX, y: buttonAction.frame.midY)
            let width = self.view.bounds.width
            let height: CGFloat = 100
            let uiView = MediaPlayer(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
            self.view.addSubview(uiView)
        self.buttonAction.center.y += 200
        UIView.animate(withDuration: 1.0) {
            self.view.layoutIfNeeded()
        }
    }
    
    func setupButton() {
        self.view.addSubview(buttonAction)
        buttonAction.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        buttonAction.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant:  -70).isActive = true
        buttonAction.heightAnchor.constraint(equalToConstant: 50).isActive = true
        buttonAction.widthAnchor.constraint(equalToConstant: 100).isActive = true
        
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.backgroundColor = .gray
        setupButton()
        
    }


}