ios - Swift:使用编程大小的 UIView 制作垂直滚动提要

Question

我正在使用从数据库 (firebase) 获取的数据在我的应用中构建一个滚动提要。我在 Swift 方面不是很有经验，因为我所做的大部分工作都是网页设计。我正在寻找的是调整 UIView 高度的好方法。这是我目前拥有的(固定高度):

这是我的 UIView 类代码:

class eventView: UIView {

    let eventDate : UILabel = {
        let eventDate = UILabel()
        eventDate.translatesAutoresizingMaskIntoConstraints = false
        eventDate.numberOfLines = 0
        eventDate.textAlignment = .center
        return eventDate
    }()
    let eventTitle : UILabel = {
    Same thing as eventDate
    }()
    let eventDesc : UILabel = {
    same thing as eventDate
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = UIColor.lightGray
        self.layer.cornerRadius = 10
        self.addSubview(eventDate)
        eventDate.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        eventDate.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        self.addSubview(eventTitle)
        eventTitle.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        eventTitle.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        eventTitle.topAnchor.constraint(equalTo: eventDate.bottomAnchor).isActive = true

        self.addSubview(eventDesc)
        eventDesc.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
        eventDesc.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
        eventDesc.topAnchor.constraint(equalTo: eventTitle.bottomAnchor).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

这是显示这些 UIView 的列表:

    var i = 0
    for data in self.eventViewData {
        let view = eventView(frame: CGRect(x: 0, y: ( CGFloat(170 * i)), width: self.scrollView.frame.width - 20, height: CGFloat(150)))
        view.center.x = self.scrollView.center.x
        view.eventDate.text = data.date
        view.eventTitle.text = data.title
        view.eventDesc.text = data.description
        self.scrollView.addSubview(view)

        i += 1
    }

我通常使用 HTML div 等，所以我很难弄清楚如何设置它们的样式。任何关于如何以编程方式调整对我的事件 View 中的 UILabel 的约束的信息或教程链接也很受欢迎。

Answer 1

如何计算所需的高度似乎是个问题。虽然有很多方法可以做到这一点，但其中一种方法是这样的:

    func heightForView(text:String, font:UIFont, width:CGFloat) -> CGFloat{
        let label:UILabel = UILabel(frame: CGRectMake(0, 0, width, CGFloat.greatestFiniteMagnitude))
        label.numberOfLines = 0
        label.lineBreakMode = NSLineBreakMode.byWordWrapping
        label.font = font
        label.text = text
        label.sizeToFit()
        return label.frame.height
}

    let font = UIFont(name: "Helvetica", size: 20.0)
    var height = heightForView("This is just a load of text", font: font, width: 100.0)
    // apply height to desired view

我更喜欢自己将 heightForView 函数放在一个扩展中，但这不是必需的。