在UIWebView上显示背景图像

import UIKit

class CustomUIWebView: UIWebView {
    override func drawRect(rect: CGRect) {
        let image = UIImage(named: "background_image.png")
        image?.drawAsPatternInRect(rect)
    }
}

let webView = CustomUIWebView(frame: CGRectMake(0, 0, 320, 480))
webView.loadRequest(NSURLRequest(URL: NSURL(string: "https://www.example.com")!))
view.addSubview(webView)