Swift 按钮自动布局编程？

嘿，伙计们，我想把我的按钮放在屏幕的下部，但是我没有得到正确的代码。按钮太小，太大，在右边或左边的角落，。。。但是它应该集中在下屏幕的中间。

我用以下代码进行了尝试：

nextButton.translatesAutoresizingMaskIntoConstraints = false
        
        nextButton.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        nextButton.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        nextButton.widthAnchor.constraint(equalTo: view.widthAnchor, constant: 97)
        nextButton.heightAnchor.constraint(equalTo: view.heightAnchor, constant: 50)

或

---

有人能告诉我怎么做才能让它工作吗？我认为使用topAnchor会非常简单：（

这将把它定位在屏幕的底部中央

nextButton.translatesAutoresizingMaskIntoConstraints = false
    
NSLayoutConstraint.activate([
    nextButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
    nextButton.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant:-20),
    nextButton.widthAnchor.constraint(equalToConstant: 50),
    nextButton.heightAnchor.constraint(equalToConstant: 50) 
])

---

问题是您使用的是centerYAnchor而不是bottomAnchor

替换

nextButton.centerYAnchor.constraint(equalTo: view.centerYAnchor)

与

nextButton.centerYAnchor.constraint(equalTo: view.centerYAnchor)

let spacingConstant = 10.0
nextButton.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -spacingConstant)