UIButton不粘在UIView邊緣

Question

嗨，謝謝你。 我正在嘗試將兩個UIButton綁定到UIViewController的view如下所示：

首先通過聲明它們：

fileprivate var deleteButton: UIButton = UIButton(type: .system)
fileprivate var addButton: UIButton = UIButton(type: .system)

接下來進行設置：

private func setupButtons() {

    deleteButton.setTitle("Delete", for: .normal)
    addButton.setTitle("Add", for: .normal)

    deleteButton.sizeToFit()
    addButton.sizeToFit()

    deleteButton.alpha = 1
    addButton.alpha = 1

    view.addSubview(deleteButton)
    view.addSubview(addButton)

    view.addConstraint(NSLayoutConstraint(item: deleteButton,
                                          attribute: .leading,
                                          relatedBy: .equal,
                                          toItem: view,
                                          attribute: .leading,
                                          multiplier: 1.0,
                                          constant: 0))

    view.addConstraint(NSLayoutConstraint(item: deleteButton,
                                          attribute: .bottom,
                                          relatedBy: .equal,
                                          toItem: view,
                                          attribute: .bottom,
                                          multiplier: 1.0,
                                          constant: 0))

    view.addConstraint(NSLayoutConstraint(item: addButton,
                                          attribute: .trailing,
                                          relatedBy: .equal,
                                          toItem: view,
                                          attribute: .trailing,
                                          multiplier: 1.0,
                                          constant: 0))

    view.addConstraint(NSLayoutConstraint(item: addButton,
                                          attribute: .bottom,
                                          relatedBy: .equal,
                                          toItem: view,
                                          attribute: .bottom,
                                          multiplier: 1.0,
                                          constant: 0))

}

但是運行模擬器會將兩個UIButton粘在左上角，這是分配給它們的默認CGRect框架。

您知道我在做什么錯嗎？ 我覺得我已經接近了，但也許與重繪視圖有關嗎？

Answer 1

您應該將translatesAutoresizingMaskIntoConstraints設置為false

// before activate constraint

deleteButton.translatesAutoresizingMaskIntoConstraints = false
addButton.translatesAutoresizingMaskIntoConstraints = false

另外，您必須設置isActive = true而不是使用addConstraint方法