ios - 快速滑动导航调整 View Controller 大小

Question

我正在尝试使用本教程使用 View Controller 而不是 xib 文件进行滑动导航:https://www.youtube.com/watch?v=3jAlg5BnYUU

我已经设法用 View Controller 替换 xib 文件，但是当我运行应用程序时， View Controller 的宽度小于正常宽度:

我不明白，因为它的设置与 xib 文件相同。有人知道如何解决这个问题吗？

这是我的代码:

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var scrollView: UIScrollView!

override func viewDidLoad() {
    super.viewDidLoad()

    let vc0 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController0")

    self.addChildViewController(vc0!)
    self.scrollView.addSubview(vc0!.view)
    vc0!.didMoveToParentViewController(self)


    let vc1 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController1")

    var frame1 = vc1!.view.frame
    frame1.origin.x = self.view.frame.size.width
    vc1!.view.frame = frame1

    self.addChildViewController(vc1!)
    self.scrollView.addSubview(vc1!.view)
    vc1!.didMoveToParentViewController(self)


    let vc2 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController2")

    var frame2 = vc2!.view.frame
    frame2.origin.x = self.view.frame.size.width * 2
    vc2!.view.frame = frame2

    self.addChildViewController(vc2!)
    self.scrollView.addSubview(vc2!.view)
    vc2!.didMoveToParentViewController(self)


    let vc3 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController3")

    var frame3 = vc3!.view.frame
    frame3.origin.x = self.view.frame.size.width * 3
    vc3!.view.frame = frame3

    self.addChildViewController(vc3!)
    self.scrollView.addSubview(vc3!.view)
    vc3!.didMoveToParentViewController(self)


    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * 4, self.view.frame.size.height - 66)


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

Answer 1

请注意，手动使用 viewDidLoad 来设置框架有点冒险，应该避免，因为未设置边界。相反，请使用 viewDidLayoutSubviews 来执行此操作，但请看一下，因为当 UI 元素发生更改(包括约束)时，该方法会一直被调用。

    var scrollViewAdded = false

override func viewDidLayoutSubviews() {

    super.viewDidLayoutSubviews()

    if !scrollViewAdded {

        self.loadSrollView()

        self.scrollViewAdded = true
    }
}


func loadSrollView() {

    self.scrollView.pagingEnabled = true

    let vc0 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController0")

    self.addChildViewController(vc0!)
    self.scrollView.addSubview(vc0!.view)
    vc0!.didMoveToParentViewController(self)

    let vc1 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController1")

    var frame1 = vc1!.view.frame
    frame1.origin.x = self.view.frame.size.width
    vc1!.view.frame = frame1

    self.addChildViewController(vc1!)
    self.scrollView.addSubview(vc1!.view)
    vc1!.didMoveToParentViewController(self)

    let vc2 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController2")

    var frame2 = vc2!.view.frame
    frame2.origin.x = self.view.frame.size.width * 2
    vc2!.view.frame = frame2

    self.addChildViewController(vc2!)
    self.scrollView.addSubview(vc2!.view)
    vc2!.didMoveToParentViewController(self)

    let vc3 = self.storyboard?.instantiateViewControllerWithIdentifier("ViewController3")

    var frame3 = vc3!.view.frame
    frame3.origin.x = self.view.frame.size.width * 3
    vc3!.view.frame = frame3

    self.addChildViewController(vc3!)
    self.scrollView.addSubview(vc3!.view)
    vc3!.didMoveToParentViewController(self)

    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * 4, self.view.frame.size.height - 66)
}