如何以编程方式从视图控制器绘制一条线？

import UIKit

class LineView: UIView {
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        
        // 获取绘图上下文
        guard let context = UIGraphicsGetCurrentContext() else { return }
        
        // 设置线条颜色
        context.setStrokeColor(UIColor.black.cgColor)
        
        // 设置线条宽度
        context.setLineWidth(2.0)
        
        // 设置线条起点
        context.move(to: CGPoint(x: 0, y: rect.height / 2))
        
        // 设置线条终点
        context.addLine(to: CGPoint(x: rect.width, y: rect.height / 2))
        
        // 绘制线条
        context.strokePath()
    }
}

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建LineView实例
        let lineView = LineView(frame: CGRect(x: 0, y: 100, width: view.bounds.width, height: 2))
        
        // 将LineView添加到当前视图控制器的视图中
        view.addSubview(lineView)
    }
}