Swift - 如何按文本长度设置自定义视图

Question

这是我的代码，

func bannerNotification(text: String){
    let container = UIView()
    let image = UIImageView()
    let label = UILabel()
    container.frame = CGRect(x: 0, y:0, width: self.view.frame.size.width, height: 100)
    container.backgroundColor = .blue
    image.frame = CGRect(x: 15, y: 50, width: 30, height: 30)
    image.image = UIImage(named: "passport")
    label.frame = CGRect(x: image.bounds.maxX + 35, y: 50, width: container.frame.size.width - 100, height: 50)
    label.backgroundColor = .red
    label.numberOfLines = 0
    label.font = UIFont(name:"Helvetica Neue", size: 15)
    label.text = text
    container.addSubview(image)
    container.addSubview(label)
    self.view.addSubview(container)
}

根据此代码，容器和图像位于正确位置，但如果我传递小文本，因此我的文本不与图像内联，则意味着 我的图像顶部位置和文本顶部位置应该相同 .

如果我要传递一个大文本，那么 容器底部和标签底部应该是相同的，并且所有文本都应该没有被截断，图像和标签应该从顶部内联.

Answer 1

您确实想为此使用自动布局，特别是因为您使用的是多行标签——也就是说，它的高度会有所不同。

这是一个示例 - 通读 cmets 以了解自动布局约束：

class KingViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        bannerNotification(text: "Banner Test")
        //bannerNotification(text: "Banner Test with lots of text to wrap onto multiple lines. Of the many advantages with using auto-layout, notice that the banner will stretch when you rotate the device.")
    }

    func bannerNotification(text: String){
        let container = UIView()
        let image = UIImageView()
        let label = UILabel()
        container.addSubview(image)
        container.addSubview(label)
        self.view.addSubview(container)
        
        [image, label, container].forEach {
            $0.translatesAutoresizingMaskIntoConstraints = false
        }

        container.backgroundColor = UIColor(red: 0.0, green: 0.5, blue: 1.0, alpha: 1.0)
        //image.image = UIImage(named: "passport")
        image.image = UIImage(named: "swiftRed")
        label.backgroundColor = .yellow
        label.numberOfLines = 0
        label.font = UIFont(name:"Helvetica Neue", size: 15)
        label.text = text

        // respect the safe area
        let g = view.safeAreaLayoutGuide
        
        NSLayoutConstraint.activate([
            
            // constrain container Top / Leading / Trailing
            container.topAnchor.constraint(equalTo: view.topAnchor),
            container.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            container.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            
            // we'll use the label height to determine the container height
            
            // image view Top = 8 / Leading = 15
            image.topAnchor.constraint(equalTo: g.topAnchor, constant: 8.0),
            image.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 15.0),
            
            // image view width = 30 / height == width (1:1 ratio)
            image.widthAnchor.constraint(equalToConstant: 30.0),
            image.heightAnchor.constraint(equalTo: image.widthAnchor),
            
            // label Top aligned to Top of image view
            label.topAnchor.constraint(equalTo: image.topAnchor),
            
            // label Leading == image view Trailing + 20
            label.leadingAnchor.constraint(equalTo: image.trailingAnchor, constant: 20.0),
            
            // label Trailing = container Trailing - 15
            label.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: -15.0),

            // container bottom should be
            //  At Least 8-pts below the image view bottom
            // AND
            //  At Least 8-pts below the label bottom
            container.bottomAnchor.constraint(greaterThanOrEqualTo: image.bottomAnchor, constant: 8.0),
            container.bottomAnchor.constraint(greaterThanOrEqualTo: label.bottomAnchor, constant: 8.0),

        ])
        
    }

}

结果，短文本：

长文本结果：

请注意，它会在大小变化时自动调整 - 例如设备旋转：