UISegmentedControl的程序約束不起作用

Question

我正在嘗試使用UIKit編程約束來創建一個簡單的界面，在該界面的左側是一個帶有UISegmentedControl的行，右側是一個黃色的UIView。

問題是我希望UIView可以擴展到整個視圖高度，但是由於某種原因，它的底部錨點不在段控制器的實際底部。

這是代碼

parentGuide = top.layoutMarginsGuide

let choices = UISegmentedControl(items: ["Op1", "Op2"])
choices.translatesAutoresizingMaskIntoConstraints = false
top.addSubview(choices)
choices.leadingAnchor.constraint(equalTo: parentGuide.leadingAnchor).isActive = true
choices.topAnchor.constraint(equalTo: parentGuide.topAnchor).isActive = true

let yellow = UIView()
yellow.translatesAutoresizingMaskIntoConstraints = false
top.addSubview(yellow)
yellow.backgroundColor = UIColor.yellow
yellow.trailingAnchor.constraint(equalTo: parentGuide.trailingAnchor).isActive = true
yellow.topAnchor.constraint(equalTo: parentGuide.topAnchor).isActive = true
yellow.leadingAnchor.constraint(equalTo: parentGuide.trailingAnchor, constant: -40).isActive = true
yellow.bottomAnchor.constraint(equalTo: choices.layoutMarginsGuide.bottomAnchor).isActive = true

為什么會發生這種情況，我該如何解決？

Answer 1

代替

yellow.bottomAnchor.constraint(equalTo: choices.layoutMarginsGuide.bottomAnchor).isActive = true

做了

yellow.bottomAnchor.constraint(equalTo: choices.bottomAnchor).isActive = true