問題描述

我正在嘗試創(chuàng)建一個只占用部分屏幕的滾動頁面視圖控制器.我已經(jīng)使用 Storyboard 和 ContainerView 對象成功完成了這項工作，但我現(xiàn)在需要復(fù)制以編程方式創(chuàng)建項目的功能.

I am trying to create a scrolling pageviewcontroller that only takes up part of my screen. I have successfully done this using Storyboard and a ContainerView object, but I now need to replicate the functionality creating the project programmatically.

似乎 ContainerView 不是我可以使用 swift 創(chuàng)建的東西，所以我嘗試使用 UIView 作為容器來執(zhí)行此操作，我嘗試使用 UIPageViewController 執(zhí)行 addSubview，但我收到錯誤 cannot將 UIPageViewController 類型的值轉(zhuǎn)換為預(yù)期的參數(shù)類型 UIView.

It seems that ContainerView is not something that I can create using swift, so I tried to do this using a UIView to act as a container that I tried to do addSubview with a UIPageViewController, but I get the error cannot convert value of type UIPageViewController to expected argument type UIView.

我認為我必須在這里遺漏一些簡單的東西，因為正如我所說，我已經(jīng)使用 Storyboard/Interface Builder 完成了這一點，但是如何在使用 Swift 以編程方式構(gòu)建時獲得類似的功能?

I assume that I must be missing something simple here, since as I said, I've accomplished this with Storyboard/Interface Builder, but how can I get similar functionality while building programmatically with Swift?

推薦答案

UIContainerView 實際上只是一個 Storyboard 的便利.它添加了一個普通的 UIView 并允許你連接一個 View Controller 作為它的嵌入內(nèi)容".

UIContainerView is really just a Storyboard convenience. It adds a normal UIView and allows you to connect a View Controller as its "embedded content."

但是，在幕后，它正在做你可以通過代碼做的事情:

But, under the hood, it is doing exactly what you can do from code:

• 將 UIView 添加到您將用作容器"的主視圖中
• 實例化您的頁面視圖控制器
• 使用 addChild(_ childController: UIViewController) 將該頁面視圖控制器添加為子控制器
• 將子 VC 的視圖添加到您的容器"視圖中

• add a UIView to your main view that you will use as the "container"
• instantiate your page view controller
• use addChild(_ childController: UIViewController) to add that page view controller as a child controller
• add the child VC's view to your "container" view

這是一個完整的例子:

//
//  Created by Don Mag on 5/31/19.
//

import UIKit

// simple example view controller
// has a label 90% of the width, centered X and Y
class ExampleViewController: UIViewController {

    let theLabel: UILabel = {
        let v = UILabel()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .white
        v.textAlignment = .center
        return v
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(theLabel)
        NSLayoutConstraint.activate([
            theLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            theLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            theLabel.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.9),
            ])

    }

}

// example Page View Controller
class MyPageViewController: UIPageViewController {

    let colors: [UIColor] = [
        .red,
        .green,
        .blue,
        .cyan,
        .yellow,
        .orange
    ]

    var pages: [UIViewController] = [UIViewController]()

    override init(transitionStyle style: UIPageViewController.TransitionStyle, navigationOrientation: UIPageViewController.NavigationOrientation, options: [UIPageViewController.OptionsKey : Any]? = nil) {
        super.init(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        dataSource = self
        delegate = nil

        // instantiate "pages"
        for i in 0..<colors.count {
            let vc = ExampleViewController()
            vc.theLabel.text = "Page: (i)"
            vc.view.backgroundColor = colors[i]
            pages.append(vc)
        }

        setViewControllers([pages[0]], direction: .forward, animated: false, completion: nil)
    }

}

// typical Page View Controller Data Source
extension MyPageViewController: UIPageViewControllerDataSource {
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {

        guard let viewControllerIndex = pages.index(of: viewController) else { return nil }

        let previousIndex = viewControllerIndex - 1

        guard previousIndex >= 0 else { return pages.last }

        guard pages.count > previousIndex else { return nil }

        return pages[previousIndex]
    }

    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        guard let viewControllerIndex = pages.index(of: viewController) else { return nil }

        let nextIndex = viewControllerIndex + 1

        guard nextIndex < pages.count else { return pages.first }

        guard pages.count > nextIndex else { return nil }

        return pages[nextIndex]
    }
}

// typical Page View Controller Delegate
extension MyPageViewController: UIPageViewControllerDelegate {

    // if you do NOT want the built-in PageControl (the "dots"), comment-out these funcs

    func presentationCount(for pageViewController: UIPageViewController) -> Int {
        return pages.count
    }

    func presentationIndex(for pageViewController: UIPageViewController) -> Int {

        guard let firstVC = pageViewController.viewControllers?.first else {
            return 0
        }
        guard let firstVCIndex = pages.index(of: firstVC) else {
            return 0
        }

        return firstVCIndex
    }
}

class MyTestViewController: UIViewController {

    let myContainerView: UIView = {
        let v = UIView()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.backgroundColor = .gray
        return v
    }()

    var thePageVC: MyPageViewController!

    override func viewDidLoad() {
        super.viewDidLoad()

        // add myContainerView
        view.addSubview(myContainerView)

        // constrain it - here I am setting it to
        //  40-pts top, leading and trailing
        //  and 200-pts height
        NSLayoutConstraint.activate([
            myContainerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 40.0),
            myContainerView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
            myContainerView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -40.0),
            myContainerView.heightAnchor.constraint(equalToConstant: 200.0),
            ])

        // instantiate MyPageViewController and add it as a Child View Controller
        thePageVC = MyPageViewController()
        addChild(thePageVC)

        // we need to re-size the page view controller's view to fit our container view
        thePageVC.view.translatesAutoresizingMaskIntoConstraints = false

        // add the page VC's view to our container view
        myContainerView.addSubview(thePageVC.view)

        // constrain it to all 4 sides
        NSLayoutConstraint.activate([
            thePageVC.view.topAnchor.constraint(equalTo: myContainerView.topAnchor, constant: 0.0),
            thePageVC.view.bottomAnchor.constraint(equalTo: myContainerView.bottomAnchor, constant: 0.0),
            thePageVC.view.leadingAnchor.constraint(equalTo: myContainerView.leadingAnchor, constant: 0.0),
            thePageVC.view.trailingAnchor.constraint(equalTo: myContainerView.trailingAnchor, constant: 0.0),
            ])

        thePageVC.didMove(toParent: self)
    }

}

結(jié)果:

這篇關(guān)于以編程方式創(chuàng)建部分屏幕 UIPageViewController的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！