在视图中使用 textview 自动布局 [Swift]

Question

我正在尝试在主视图中创建两个视图，这些视图由 textView 自动调整大小，我想添加第一个视图，然后通过单击按钮添加秒数，但我遇到了一些错误。但我不想对主视图设置等高约束，它必须根据其 2 个子视图中的文本视图调整大小这是我的代码片段和我的意思的图像：

        @objc func buttonAction() {
            print("action")

            mainView.addSubview(secondView)

            firstView.topAnchor.constraint(equalTo: mainView.topAnchor).isActive = false
            // I've tried to disable it to change the topAnchor of firstView 

            NSLayoutConstraint.activate([

                secondView.bottomAnchor.constraint(equalTo: firstView.topAnchor),
                secondView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor),
                secondView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor),
                secondView.topAnchor.constraint(equalTo: mainView.topAnchor)
            ])
        }

        func addConstraints() {

            NSLayoutConstraint.activate([

                firstView.topAnchor.constraint(equalTo: mainView.topAnchor),
                firstView.bottomAnchor.constraint(equalTo: mainView.bottomAnchor),
                firstView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor),
                firstView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor),
            ])

            NSLayoutConstraint.activate([
                mainView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
                mainView.centerXAnchor.constraint(equalTo: view.centerXAnchor)
            ])
        }

        class View1: UIView { // the same as View2 class

        lazy var textView: UITextView = {
           let tv = UITextView()
            tv.backgroundColor = .red
            tv.isScrollEnabled = false
            tv.font = UIFont(name: "Avenir", size: 16)
            tv.text = "First"
            tv.translatesAutoresizingMaskIntoConstraints = false
            return tv
        }()

        init() {
            super.init(frame: .zero)
            setup()
        }

        required init?(coder: NSCoder) {
            fatalError()
        }

        func setup() {
            addSubview(textView)

            textView.fillSuperview(padding: .init(top: 4, left: 4, bottom: 4, right: 4))
            // fillSuperview() put 4 in top,left,right,bottom of superview

        }
    }

这是我的意思的图片：

Answer 1

您需要保存对 firstView 顶部约束的引用并停用该引用。您试图停用对 firstView 顶部约束的新引用。

class ViewController: UIViewController {

    var firstViewTop: NSLayoutConstraint!

    func addConstraints() {

        firstViewTop = firstView.topAnchor.constraint(equalTo: mainView.topAnchor)
        NSLayoutConstraint.activate([
            firstViewTop,
            firstView.bottomAnchor.constraint(equalTo: mainView.bottomAnchor),
            firstView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor),
            firstView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor),
        ])

        NSLayoutConstraint.activate([
            mainView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            mainView.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        ])
    }

    @objc func buttonAction() {
        mainView.addSubview(secondView)
        firstViewTop.isActive = false

        NSLayoutConstraint.activate([
            secondView.bottomAnchor.constraint(equalTo: firstView.topAnchor),
            secondView.leadingAnchor.constraint(equalTo: mainView.leadingAnchor),
            secondView.trailingAnchor.constraint(equalTo: mainView.trailingAnchor),
            secondView.topAnchor.constraint(equalTo: mainView.topAnchor)
        ])
    }

}

在视图中使用 textview 自动布局 [Swift]

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