Swift：以編程方式自動布局底部錨點無法正常工作

Question

我在代碼中為我的按鈕設置了約束，這就是我的代碼的樣子：

       addSubview(stackViewOne)
       
       stackViewOne.bottomAnchor.constraint(equalTo: bottomAnchor, constant: -250).isActive = true
       stackViewOne.leftAnchor.constraint(equalTo: leftAnchor, constant: 20).isActive = true
       stackViewOne.rightAnchor.constraint(equalTo: rightAnchor, constant: -20).isActive = true
       stackViewOne.heightAnchor.constraint(equalToConstant: frame.size.height * 0.065).isActive = true

但現在我的底錨有問題。 我想從底部使我的stackview 80。 只有當我輸入八十作為距離時，我的堆棧視圖才會顯示。 只有當我在負范圍內輸入一個非常高的值時，才會顯示堆棧視圖。 （等於：bottomAnchor，常量：-250）

有誰知道為什么？ 此致

Answer 1

您通常不需要在 stackview 上指定高度約束 - stackview 本身將通過其排列的子視圖（標簽？）來調整大小。 我將首先刪除該約束。 確保您排列的子視圖具有大小，並且您的堆棧視圖的間距/對齊等配置正確。

也可能 safeArea / layoutMargins 干擾您的布局 - 但如果沒有更多代碼就不可能知道。

Answer 2

I created a UIView class and there I created objects look: import UIKit `` class TimerSequenzeView: UIView {

lazy var plusButton: UIButton = {
    let btn = UIButton(type: .system)
    btn.setTitle("5", for: .normal)
    btn.titleLabel?.font = .systemFont(ofSize: 35)
    btn.titleLabel?.font = UIFont(name: "Arial", size: 35)
    btn.setTitleColor(.red, for: .normal)
    btn.layer.borderColor = UIColor.red.cgColor
    btn.layer.borderWidth = 3
    btn.layer.cornerRadius = 30
    btn.setImage(UIImage(systemName: "plus"), for: .normal)
    btn.tintColor = .red
    btn.translatesAutoresizingMaskIntoConstraints = false
    
    return btn
}()

lazy var minusButton: UIButton = {
    let btn = UIButton(type: .system)
    btn.setTitle("5", for: .normal)
    btn.titleLabel?.font = .systemFont(ofSize: 35)
    btn.titleLabel?.font = UIFont(name: "Arial", size: 35)
    btn.setTitleColor(.red, for: .normal)
    btn.layer.borderColor = UIColor.red.cgColor
    btn.layer.borderWidth = 3
    btn.layer.cornerRadius = 30
    btn.setImage(UIImage(systemName: "minus"), for: .normal)
    btn.tintColor = .red
    btn.translatesAutoresizingMaskIntoConstraints = false
    
    return btn
}()

lazy var stackViewOne: UIStackView = {
    let stackView = UIStackView()
    stackView.axis = .horizontal
    stackView.distribution = .fillEqually
    stackView.spacing = 20
    stackView.translatesAutoresizingMaskIntoConstraints = false
    
    stackView.addArrangedSubview(plusButton)
    stackView.addArrangedSubview(minusButton)
    
    return stackView
}()


override init(frame: CGRect) {
    super.init(frame: frame)
    setConstrains()
}

required init?(coder: NSCoder) {
    super.init(coder: coder)
}


func setConstrains() {
    addSubview(stackViewOne)

    stackViewOne.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -80).isActive = true
    stackViewOne.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 20).isActive = true
    stackViewOne.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -20).isActive = true
    stackViewOne.heightAnchor.constraint(equalToConstant: frame.size.height * 0.065).isActive = true
}

}