ios - 为什么我的 View Controller 没有显示在 ScrollView Controller 上？

Question

我有三步 View Controller 。我试图使用 ScrollView 在单个 View Controller (RegisterViewController)上显示这三个步骤，以便用户可以滑动这些步骤。

我看到了其他一些帖子并了解到了这一点。当我运行该应用程序时，我得到一个带有 RegisterViewController 背景颜色的空白屏幕。我在步骤 View Controller 中编写了一些 println 语句来检查它们是否正在实例化，并且我可以在控制台上看到这些语句的输出。请问有人可以帮忙吗？

class RegisterViewController: UIViewController {

  @IBOutlet weak var scrollView: UIScrollView!
  @IBOutlet weak var registerStepsPageControl: UIPageControl!

  override func viewDidLoad() {
    super.viewDidLoad()
    setupScrollView()
  }

  func setupScrollView() {
    let storyboard = UIStoryboard(name: "Login", bundle: nil)
    let stepOneViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepOne") as! RegisterStepOneViewController
    let stepTwoViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepTwo") as! RegisterStepTwoViewController
    let stepThreeViewController = storyboard.instantiateViewControllerWithIdentifier("RegisterStepThree") as! RegisterStepThreeViewController

    var stepViewControllers = [stepOneViewController, stepTwoViewController, stepThreeViewController]

    for index in 0..<stepViewControllers.count {
      self.addChildViewController(stepViewControllers[index])

      let originX: CGFloat = CGFloat(index) * CGRectGetWidth(self.scrollView.frame);
      stepViewControllers[index].view.frame = CGRectMake(originX, 0, self.view.frame.size.width, self.view.frame.size.height);
      stepViewControllers[index].view.frame.size = self.view.frame.size
      self.scrollView.addSubview(stepViewControllers[index].view)
      stepViewControllers[index].didMoveToParentViewController(self)
    }
    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepViewControllers.count), self.view.frame.height)
    self.scrollView.delegate = self
    self.registerStepsPageControl.numberOfPages = stepViewControllers.count
  }
}

编辑01: 下面的代码有效。它加载图像并且它们按预期显示。但我不知道从其他 View Controller 加载 View 时可能会出现什么问题。

@IBOutlet weak var tutorialStepsPageControl: UIPageControl!

@IBOutlet weak var scrollView: UIScrollView!

var stepImages: [UIImage] = [UIImage(named: "tutorial_image_step1")!, UIImage(named: "tutorial_image_step2")!, UIImage(named: "tutorial_image_step3")!]


override func viewDidLoad() {
  super.viewDidLoad()
  self.tutorialStepsPageControl.numberOfPages = stepImages.count
  setupScrollView()
}

func setupScrollView() {
  var imageFrame: CGRect = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)
  var imageView: UIImageView!

  for index in 0..<stepImages.count {
    imageFrame.origin.x = self.view.frame.size.width * CGFloat(index)
    imageFrame.size = self.view.frame.size

    imageView = UIImageView(frame: imageFrame)
    imageView.image = stepImages[index]
    imageView.contentMode = .ScaleAspectFit
    self.scrollView.addSubview(imageView)
  }

  self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepImages.count), self.view.frame.size.height)
  self.scrollView.delegate = self
}

Answer 1

尝试移动线条:

self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(stepViewControllers.count), self.view.frame.height)

此行上方:

for index in 0..<stepViewControllers.count {

此问题可能是由于您在发送 contentSize 之前添加 subview 所致。