用代码创建图像并将其显示到UIImageView中

// 创建一个自定义颜色的UIImage
func createImageWithColor(_ color: UIColor, size: CGSize) -> UIImage {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
    color.setFill()
    UIRectFill(rect)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image!
}

// 假设你有一个UIImageView实例叫做imageView
let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))

// 创建一个红色的UIImage
let redImage = createImageWithColor(.red, size: CGSize(width: 200, height: 200))

// 将UIImage设置到UIImageView
imageView.image = redImage

// 将UIImageView添加到你的视图层级中
view.addSubview(imageView)

UIGraphicsBeginImageContextWithOptions(size, opaque, UIScreen.main.scale)