避免在水平紧凑环境下弹出适应全屏答案

【问题标题】：Avoid popover adapting to fullscreen in horizontally compact environment避免在水平紧凑环境下弹出适应全屏
【发布时间】：2020-11-01 15:03:33
【问题描述】：

根据documentation，

在水平紧凑的环境中，弹出框适应 UIModalPresentationOverFullScreen 默认呈现样式。

见下图。在紧凑的环境中，popover 从底部出现并动画到顶部直到覆盖整个屏幕。

是否可以覆盖此行为并让弹出框仅覆盖屏幕的特定高度，如下所示？

以下代码演示了在紧凑环境中弹出框适应全屏演示样式的默认行为。

import UIKit

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = .systemBackground
        
        let button = UIButton()
        button.translatesAutoresizingMaskIntoConstraints = false
        button.setImage(UIImage(systemName: "square.grid.2x2.fill"), for: .normal)
        button.addTarget(self, action: #selector(displayPopover), for: .touchUpInside)
        self.view.addSubview(button)
        
        NSLayoutConstraint.activate([
            button.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 100),
            button.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
            button.widthAnchor.constraint(equalToConstant: 40),
            button.heightAnchor.constraint(equalToConstant: 40),
        ])
        
    }
    
    @IBAction func displayPopover(sender: UIButton!) {
        let popoverVC = PopoverViewController()
        popoverVC.preferredContentSize = CGSize(width: 300, height: 200)
        popoverVC.modalPresentationStyle = .popover
        popoverVC.popoverPresentationController?.sourceView = sender
        popoverVC.popoverPresentationController?.permittedArrowDirections = .up
        self.present(popoverVC, animated: true, completion: nil)
    }
    
    
}

class PopoverViewController: UIViewController {
    override func viewDidLoad() {
        self.view.backgroundColor = .systemGray
    }
}

输出：

谢谢你????‍♂️

【问题讨论】：

标签： ios swift popover

【解决方案1】：

iOS 15 现已提供此功能。

观看 WWDC2021 短片video

从here下载WWDC示例项目

 @IBAction func showImagePicker(_ sender: UIBarButtonItem) {
    
    let imagePicker = UIImagePickerController()
    imagePicker.delegate = self
    imagePicker.modalPresentationStyle = .popover
    if let popover = imagePicker.popoverPresentationController {
        popover.barButtonItem = sender
        
        let sheet = popover.adaptiveSheetPresentationController
        sheet.detents = [.medium(), .large()]
        sheet.largestUndimmedDetentIdentifier = .medium
        sheet.prefersScrollingExpandsWhenScrolledToEdge = false
        sheet.prefersEdgeAttachedInCompactHeight = true 
        sheet.widthFollowsPreferredContentSizeWhenEdgeAttached = true
    }
    
    present(imagePicker, animated: true, completion: nil)
}

【讨论】：