如何保持UIButton在scrollViewDidScroll（_ scrollView：UIScrollView）到达底部后浮动？

Question

以下是当前的实施。灰色按钮浮动在滚动视图上。是否有一种方法可以在黄色视图（滚动视图的结束）到达时显示按钮。然后保持它在最底部的屏幕上浮动。

我用下面的代码：

override func scrollViewDidScroll(scrollView: UIScrollView) { 

if (scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)) { 
    //reached bottom - how to show button below yellow 
    // and keep it floating as shown above 
} 
} 

添加的什么我试过到目前为止附加代码：

@IBOutlet weak var btnScroll: UIButton! 

var startingFrame : CGRect! 
var endingFrame : CGRect! 

func scrollViewDidScroll(_ scrollView: UIScrollView) { 
    if (scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)) && self.btnScroll.isHidden { 
     self.btnScroll.isHidden = false 
     self.btnScroll.frame = startingFrame // outside of screen somewhere in bottom 
     UIView.animate(withDuration: 1.0) { 
      self.btnScroll.frame = self.endingFrame // where it should be placed 
     } 
    } 
} 

func configureSizes() { 
    let screenSize = UIScreen.main.bounds 
    let screenWidth = screenSize.width 
    let screenHeight = screenSize.height 

    startingFrame = CGRect(x: 0, y: screenHeight+100, width: screenWidth, height: 100) 
    endingFrame = CGRect(x: 0, y: screenHeight-100, width: screenWidth, height: 100) 

} 

override func viewDidLoad() { 
    super.viewDidLoad() 

    configureSizes() 
} 

Answer 1

如果我理解你的权利，你想把按钮放在gif上显示的位置

试试这个代码：

override func scrollViewDidScroll(scrollView: UIScrollView) { 
    if (scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)) && self.button.isHidden { 
    self.button.isHidden = false 
    self.button.frame = startingFrame // outside of screen somewhere in bottom 
    UIView.animate(withDuration: 1.0) { 
     self.button.frame = yourFrame // where it should be placed 
    } 
    } 
} 

UPDATE

添加该代码隐藏按钮之前的动画将显示它

override func viewDidLoad() { 
    super.viewDidLoad() 
    self.button.isHidden = true 
    ... 
}