Swift:以编程方式从另一个 VC 设置 VC 框架

Question

我有两个 ViewControllers - Slider 和 Foo。我将 Slider 添加为 Foo subview 并将其框架设置在 Foo VC 中，但是 Slider 的框架没有改变 -> 我可以看到仅应用了 x 和 y 。我应该如何更改代码才能使用 Slider(initWithFrame: CGFrame) 初始化 Slider？或者从 Foo VC 设置 Slider 大小的首选方法是什么？

//slider.swift

import UIKit

class Slider: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
    var collectionView: UICollectionView?


    override func viewDidLoad() {
        super.viewDidLoad()

        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.minimumLineSpacing = 0
        layout.sectionInset = UIEdgeInsets.zero
        layout.itemSize = self.view.frame.size
        layout.scrollDirection = UICollectionViewScrollDirection.horizontal

        collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView?.dataSource = self
        collectionView?.delegate = self
        collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
        collectionView?.backgroundColor = UIColor.white
        collectionView?.isPagingEnabled = true

        self.view.addSubview(collectionView!)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 14
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
        cell.backgroundColor = UIColor.red
        return cell
    }
}

//foo.swift

import UIKit

class Foo: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        slider = Slider();
        slider!.view.frame = CGRect(x: 50, y: 50, width: 20, height: 20)
        self.view.addSubview(slider!.view)
        self.addChildViewController(slider!)
    }

}

Answer 1

您的实现似乎存在一些问题。虽然看起来框架没有改变，但实际上是这样，但是您的 View 没有剪切到边界，因此看起来框架保持不变。

有几点需要注意。

首先，如果您要在代码中进行设置和布局，则需要更新 func“viewDidLayoutSubviews”中的框架/位置。 (看起来 dfd 在评论中也提到了这一点)

还要确保您正确实现 View Controller 包含。每当您尝试将一个 View Controller 的 View 添加到另一个 View Controller 的 View 时，您都应该使用 View Controller 包含。以下是该文档的链接:View Controller Containment Docs Here

根据 Apple 的说法，您应该实现的最低限度遏制措施如下:(您基本上是正确的，但您的调用没有顺序)

func displayContentController(content: UIViewController) {
    addChildViewController(content)
    content.view.frame = frameForContentController()
    view.addSubview(content.view)
    content.didMoveToParentViewController(self)
}

我在下面的示例中包含了一个 UIViewController 扩展示例。

尝试以下代码，它在测试项目中对我有用:

import UIKit


class Slider: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

var collectionView: UICollectionView?
var layout : UICollectionViewFlowLayout?

override func viewDidLoad() {
    super.viewDidLoad()

    layout = UICollectionViewFlowLayout()
    layout?.minimumLineSpacing = 0
    layout?.sectionInset = UIEdgeInsets.zero
    layout?.itemSize = view.bounds.size
    layout?.scrollDirection = UICollectionViewScrollDirection.horizontal

    collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout!)
    collectionView?.dataSource = self
    collectionView?.delegate = self
    collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
    collectionView?.backgroundColor = UIColor.blue
    collectionView?.isPagingEnabled = true

    self.view.addSubview(collectionView!)
}

override func viewDidLayoutSubviews() {

    // update layout item size here to your new view size
    layout?.itemSize = view.bounds.size
    // update collection view frame to new view size here
    collectionView?.frame = view.bounds

    super.viewDidLayoutSubviews()
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 14
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
    cell.backgroundColor = UIColor.red
    return cell
}
}


class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    let slider = Slider()

    // note clips to bounds here, avoids confusion as to where the frame is 
    slider.view.clipsToBounds = true
    addChild(child: slider, frame: CGRect(x: 50, y: 50, width: 30, height: 30))
}


}


extension UIViewController {

// MARK: View Controller Containment convenience functions

func addChild(child:UIViewController, frame:CGRect) {
    // notify child of containment
    child.willMove(toParentViewController: self)

    // add content as child
    self.addChildViewController(child)

    // set frame of child content
    child.view.frame = frame

    // add childs view to hierarchy
    self.view.addSubview(child.view)

    // call containment delegate
    child.didMove(toParentViewController: self)
}

/*
 * Call this function on a child view controller to remove it from it's parent controller and dismiss it.
 */
func remove(fromParentWithAnimationDuration animationDuration:TimeInterval)
{
    // notify child it's being removed
    self.willMove(toParentViewController: nil)

    // remove the view
    self.view.removeFromSuperview()

    // remove child controller from container
    self.removeFromParentViewController()
}

}