Question

我想更新popover的布局，我已经尝试使用setNeedsLayout()和layoutIfNeeded()方法，但找不到解决方案。

我有一个简单的屏幕，有4个按钮，可以调用弹出框，在弹出框中有2个额外的按钮：

按钮 - ＆gt;隐藏button3，并将button1和button2移动到左侧。
重新定位 - ＆gt;将按钮的源视图从button1 / 2/3/4（发送者）更改为button4。 Picture of the layout

我遇到的问题是我无法更新/刷新屏幕，并且popover始终指向前一个源视图位置。 Picture of the popover

不知何故，我需要一个更新视图的方法，它比layoutIfNeeded()强，因为如果屏幕从纵向/横向更改，则弹出框会自动更改。 Here I changed portrait/landscape/portrait

项目的GitHub。 GitHub

使用的代码如下：

class ViewController: UIViewController, ButtonDidDisappearDelegate {

    @IBOutlet weak var button1: UIButton!
    @IBOutlet weak var button2: UIButton!
    @IBOutlet weak var button3: UIButton!
    @IBOutlet weak var button4: UIButton!

    @IBOutlet weak var constrain2: NSLayoutConstraint!

    var popVC: PopVC?

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func buttonPopover(_ sender: UIButton) {
        configureAndPresentPopover(from: sender)
    }

    func buttonDisappear() {
        self.constrain2.constant = 100
        self.button3.isHidden = !self.button3.isHidden

        if !self.button3.isHidden {
            self.constrain2.constant = 10
        }
    }

    func repositionPopover() {
        DispatchQueue.main.async {
            if let popVC = self.popVC {
                self.self.popoverPresentationController(popVC.popoverPresentationController!, willRepositionPopoverTo: self.button4.bounds, in: self.button4)
            }
            self.view.setNeedsLayout()
            self.view.layoutIfNeeded()
        }
    }
}

extension ViewController: UIPopoverPresentationControllerDelegate {

    func configureAndPresentPopover(from sender: UIButton) {

        popVC = storyboard?.instantiateViewController(withIdentifier: "popVC") as? PopVC

        guard let popVC = popVC else {
            return
        }

        popVC.popOverDelegate = self
        popVC.modalPresentationStyle = .popover

        let popOverVC = popVC.popoverPresentationController
        popOverVC?.delegate = self
        popOverVC?.sourceView = sender
        popOverVC?.sourceRect = sender.bounds
        popVC.preferredContentSize = CGSize(width: 300, height: 60)
        popOverVC?.permittedArrowDirections = .down

        self.present(popVC, animated: true)
    }

    func adaptivePresentationStyle(for controller: UIPresentationController) -> UIModalPresentationStyle {
        return .none
    }

    func popoverPresentationController(_ popoverPresentationController: UIPopoverPresentationController,
                                       willRepositionPopoverTo rect: CGRect,
                                       in view: UIView) {
        popoverPresentationController.sourceView = view
        popoverPresentationController.sourceRect = rect
    }
}

和弹出控制器：

protocol ButtonDidDisappearDelegate: class {
    func configureAndPresentPopover(from sender: UIButton)
    func buttonDisappear()
    func repositionPopover()
}

class PopVC: UIViewController {

    weak var popOverDelegate: ButtonDidDisappearDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()
    }


    @IBOutlet weak var popoverButton: UIButton!

    @IBAction func popoverAction(_ sender: Any) {
        popOverDelegate?.buttonDisappear()
        DispatchQueue.main.async {
            self.view.setNeedsLayout()
            self.view.layoutIfNeeded()
        }
    }

    @IBAction func reposition(_ sender: Any) {
        popOverDelegate?.repositionPopover()
    }
}

Answer 1

您需要指定箭头的新位置并询问演示控制器视图的布局，而不仅仅是呈现的视图。

尝试：

func repositionPopover() {
    let popOverController = presentedViewController?.presentationController as? UIPopoverPresentationController
    popOverController?.sourceView = button4
    popOverController?.containerView?.setNeedsLayout()
    popOverController?.containerView?.layoutIfNeeded()
}

（无需在主线程上发送，使用UIKit时已经在该线程上）

Answer 2

您可以尝试再次设置sourceview和sourcerect。当sourcview边界更改时，调用此函数。

当源视图在Swift中更改它们时，如何更新popover的布局（位置）？

2 个答案: