Swift：如何以编程方式创建可重用视图？

Question

假设我在描述我自己的 UIView，我们称它为 HeaderView。我希望 HeaderView 具有完全相同的属性，但仅在标签文本上有所不同。这是我目前拥有的方式：

private let headerView: UIView = {
    let screenSize = UIScreen.main.bounds
    let screenWidth = screenSize.width
    let screenHeight = screenSize.height

    let view = UIView()
    view.backgroundColor = .white
    view.heightAnchor.constraint(equalToConstant: 65).isActive = true

    let label = UILabel()
    label.font = UIFont.systemFont(ofSize: 30)
    label.textAlignment = .left
    label.textColor = .black
    label.text = "Search"

    view.addSubview(label)
    label.translatesAutoresizingMaskIntoConstraints = false
    label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 8).isActive = true
    label.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 5).isActive = true

    return view
}()

我会如何使用它：

 view.addSubview(headerView)
 headerView.translatesAutoresizingMaskIntoConstraints = false
 headerView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
 headerView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
 headerView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true

如果我想要其中 3 个带有不同文本的标题视图怎么办？我如何将其变成可重用的程序化视图？

Answer 1

您可以创建UIView 的子类并在任何地方重用它

class HeaderView: UIView {

  let innerview = UIView()
  let innerlabel = UILabel() 

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

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

private func sharedLayout() {

    self.addSubview(innerview)
    self.innerView.backgroundColor = UIColor.red
    innerview.translatesAutoresizingMaskIntoConstraints = false
    innerview.trailingAnchor.constraint(equalTo:self.trailingAnchor).isActive = true
    innerview.leadingAnchor.constraint(equalTo: self.leadingAnchor).isActive = true
    innerview.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
    innerview.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true

    // configure other items here
}

}

Answer 2

你可以有一个函数，而不是一个变量：

func buildHeaderView(withText text: String) -> UIView {
    let screenSize = UIScreen.main.bounds
    let screenWidth = screenSize.width
    let screenHeight = screenSize.height

    let view = UIView()
    view.backgroundColor = .white
    view.heightAnchor.constraint(equalToConstant: 65).isActive = true

    let label = UILabel()
    label.font = UIFont.systemFont(ofSize: 30)
    label.textAlignment = .left
    label.textColor = .black
    label.text = text

    view.addSubview(label)
    label.translatesAutoresizingMaskIntoConstraints = false
    label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 8).isActive = true
    label.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 5).isActive = true

    return view
}

现在你可以像这样使用这个函数：

let searchHeaderView = buildHeaderView(withText: "Search")
view.addSubview(searchHeaderView)

let otherView = buildHeaderView(withText: "Other")