如何调整视图的大小，同时按比例调整其子视图的大小？

Question

我正在尝试创建一个自定义 segue，其中第一个视图控制器缩小一点，第二个在它上面滑动。以下是我的 segue 实现：

override func perform() {
    let firstView = self.sourceViewController.view as UIView!
    let secondView = self.destinationViewController.view as UIView!
    let screenSize = UIScreen.mainScreen().bounds.size
    let window = UIApplication.sharedApplication().keyWindow

    secondView.frame = CGRectMake(0.0, screenSize.height, screenSize.width, screenSize.height)
    window?.insertSubview(secondView, aboveSubview: firstView)

    UIView.animateWithDuration(2, delay: 0, options: .CurveEaseIn, animations: {

        // BEGIN RELEVANT PORTION
        let offset: CGFloat = 20

        firstView.frame = CGRectMake(offset, offset, screenSize.width - (offset * 2), screenSize.height - (offset * 2))
        firstView.autoresizesSubviews = true
        firstView.layoutIfNeeded()
        // END RELEVANT PORTION

    }, completion: nil)

    UIView.animateWithDuration(5, delay: 1, options: .CurveEaseOut, animations: {

        secondView.frame = CGRectMake(0.0, 0.0, screenSize.width, screenSize.height)

    }, completion: nil)
}

这会产生如下结果：

这已经很棒了，但不是我想要的。我需要子视图（“嗨，我是 Matt。”标签和按钮）与父视图成比例地调整大小，就好像整个视图都在 z 轴上下降一样。

我正在使用自动布局。

非常感谢您！

Answer 1

我使用CGAffineTransform解决了这个问题。

override func perform() {
    let firstView = self.sourceViewController.view as UIView!
    let secondView = self.destinationViewController.view as UIView!
    let screenSize = UIScreen.mainScreen().bounds.size
    let window = UIApplication.sharedApplication().keyWindow

    secondView.frame = CGRectMake(0.0, screenSize.height, screenSize.width, screenSize.height)
    window?.insertSubview(secondView, aboveSubview: firstView)

    firstView.layer.anchorPoint = CGPoint(x: 0.0, y: 0.0)
    firstView.layer.position = CGPoint(x: 0.0, y: 0.0)

    UIView.animateWithDuration(0.2, delay: 0, options: .CurveEaseInOut, animations: {

        print(firstView.frame)

        let offset: CGFloat = 25
        let offsetX = 2 * (offset / firstView.frame.width)
        let offsetY = 2 * (offset * (firstView.frame.height / firstView.frame.width) / firstView.frame.height)

        let transform = CGAffineTransformScale(CGAffineTransformIdentity, 1 - offsetX, 1 - offsetY)
        firstView.transform = transform
        firstView.layer.position = CGPoint(x: offset, y: offset)

    }, completion: nil)

    UIView.animateWithDuration(0.5, delay: 0.05, options: .CurveEaseOut, animations: {

        secondView.frame = CGRectMake(0.0, 0.0, screenSize.width, screenSize.height)

        }) { finished -> Void in
            self.sourceViewController.presentViewController(self.destinationViewController, animated: false, completion: nil)
    }
}

谢谢大家的帮助！

Answer 2

应用变换是实现它的好方法。

还有另一种方法可以实现它，而不会修改第一个视图控制器的视图框架。拍摄第一个 viewcontroller 视图的快照并使用它而不是视图本身。您可以在 UIView 中使用以下方法来拍摄快照：

- (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates;

Answer 3

我在 Xcode 中使用您的场景进行了尝试，现在您必须按照以下步骤操作

1- Give UIButton & UILabel Leading and Trailing Space to their SuperView
2- Make UIButton central Vertically
3- Give Vertical Space from UIButton to UILabel

重要：

希望它会起作用，因为技巧是您必须为超级视图提供前导和尾随空间，以使 InnerViews 收缩或扩展其超级视图

Answer 4

一种方法可以是：

• 给它们（标签和按钮）宽度限制。
• 制作两个宽度限制的出口。 constraintWidthLabel、constraintWidthButton
• 您可以像这样解除约束

• 当您执行 segue 时，您必须通过动画将这些宽度约束设为零。

  UIView.animateWithDuration(2, delay: 0, options: .CurveEaseIn, animations: {
  
  // BEGIN RELEVANT PORTION
  let offset: CGFloat = 20
  constraintWidthLabel.constant = 0
  constraintWidthButton.constant = 0;
  
  firstView.frame = CGRectMake(offset, offset, screenSize.width - (offset * 2), screenSize.height - (offset * 2))
  firstView.autoresizesSubviews = true
  firstView.layoutIfNeeded()
  // END RELEVANT PORTION
  
  }, completion: nil)