如何使用UIPresentationController定制模態(tài)視圖的呈現(xiàn)方式

要使用UIPresentationController來(lái)定制模態(tài)視圖的呈現(xiàn)方式，首先需要?jiǎng)?chuàng)建一個(gè)自定義的PresentationController類，繼承自UIPresentationController。在這個(gè)類中，可以重寫一些方法來(lái)自定義模態(tài)視圖的呈現(xiàn)效果。

下面是一個(gè)簡(jiǎn)單的示例代碼，演示了如何使用UIPresentationController來(lái)定制模態(tài)視圖的呈現(xiàn)方式：

import UIKit

class CustomPresentationController: UIPresentationController {
    
    override var shouldRemovePresentersView: Bool {
        return true // 是否移除背景視圖
    }
    
    override func presentationTransitionWillBegin() {
        // 在模態(tài)視圖呈現(xiàn)之前執(zhí)行的操作
        let dimmingView = UIView()
        dimmingView.frame = containerView!.bounds
        dimmingView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
        dimmingView.alpha = 0.0
        containerView?.insertSubview(dimmingView, at: 0)
        
        presentedViewController.transitionCoordinator?.animate(alongsideTransition: { _ in
            dimmingView.alpha = 1.0
        }, completion: nil)
    }
    
    override func dismissalTransitionWillBegin() {
        // 在模態(tài)視圖消失之前執(zhí)行的操作
        containerView?.subviews.first?.alpha = 0.0
    }
    
    override func containerViewWillLayoutSubviews() {
        // 設(shè)置模態(tài)視圖的frame
        presentedView?.frame = frameOfPresentedViewInContainerView
    }
    
    override func size(forChildContentContainer container: UIContentContainer, withParentContainerSize parentSize: CGSize) -> CGSize {
        return CGSize(width: parentSize.width, height: parentSize.height * 0.5) // 設(shè)置模態(tài)視圖的大小
    }
    
    override var frameOfPresentedViewInContainerView: CGRect {
        guard let containerView = containerView else { return .zero }
        let presentedViewSize = size(forChildContentContainer: presentedViewController, withParentContainerSize: containerView.bounds.size)
        return CGRect(x: 0, y: containerView.bounds.height * 0.5, width: presentedViewSize.width, height: presentedViewSize.height)
    }
}

在創(chuàng)建自定義PresentationController類后，需要在呈現(xiàn)模態(tài)視圖的時(shí)候指定這個(gè)PresentationController類，例如：

let presentedViewController = YourViewController()
presentedViewController.modalPresentationStyle = .custom
presentedViewController.transitioningDelegate = self
presentedViewController.presentationController?.delegate = self

self.present(presentedViewController, animated: true, completion: nil)

需要注意的是，在使用自定義PresentationController時(shí)，需要設(shè)置模態(tài)視圖的modalPresentationStyle為.custom，并且設(shè)置transitioningDelegate為自定義PresentationController。同時(shí)，也可以設(shè)置delegate為自定義PresentationController來(lái)進(jìn)一步定制模態(tài)視圖的呈現(xiàn)方式。