swift 加载 本地html 和 网络路径

先上代码： xcode 9.4  ios 11.4

import UIKit
import WebKit

class RootViewController: UIViewController, WKNavigationDelegate {
    var webView: WKWebView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // 创建视图
        let screen = UIScreen.main.bounds
        // 按钮栏
        let buttonBarWidth:CGFloat =
        let buttonBar = UIView(frame: CGRect(x: (screen.size.width - buttonBarWidth)/, y: , width:buttonBarWidth, height: ))
        self.view.addSubview(buttonBar)

        let width = buttonBar.frame.size.width /  -
    //添加按钮
        let buttonHTML = UIButton(type: UIButtonType.system)
        buttonHTML.setTitle("通过路径加载", for: UIControlState())
        buttonHTML.frame = CGRect(x:, y:, width: width, height: )
        //添加事件
        buttonHTML.addTarget(self, action: #selector(buttonHTML(_:)), for: .touchUpInside)
        buttonBar.addSubview(buttonHTML)

    //添加 loadHTMLString 按钮
        let loadHTMLString = UIButton(type: UIButtonType.system)
        loadHTMLString.setTitle("loadHTMLString", for: UIControlState())
        loadHTMLString.frame = CGRect(x: width + , y:, width: width, height: )
        //添加事件
        loadHTMLString.addTarget(self, action: #selector(loadHTMLString(_:)), for: .touchUpInside)
        buttonBar.addSubview(loadHTMLString)

    //添加loadData按钮
        let loadData = UIButton(type: UIButtonType.system)
        loadData.setTitle("loadData", for: UIControlState())
        loadData.frame = CGRect(x:, y: , width: width, height: )
        //添加事件
        loadData.addTarget(self, action: #selector(loadData(_:)), for: .touchUpInside)
        buttonBar.addSubview(loadData)

    //添加loadRequest按钮--- 加载网络地址
        let loadRequest = UIButton(type: UIButtonType.system)
        loadRequest.setTitle("loadRequest", for: UIControlState())
        loadRequest.frame = CGRect(x: width + , y: , width: width, height: )
        //添加事件
        loadRequest.addTarget(self, action: #selector(loadRequest(_:)), for: .touchUpInside)
        buttonBar.addSubview(loadRequest)

    //添加WKWebView
        self.webView = WKWebView(frame: CGRect(x:, y: , width: screen.size.width, height: screen.size.height -  ))
        self.view.addSubview(webView)
    }
    // 加载本地html 点击事件
    @objc func buttonHTML(_ sender: AnyObject){
        // 方法一 加载路径
        let htmlPath = Bundle.main.path(forResource: "index", ofType: "html")
        if let htmlPath =  htmlPath {
            let url = URL.init(fileURLWithPath: htmlPath) // 把字符串 转成 URL 类型
            let request = URLRequest(url: url)
            self.webView.load(request)
            self.webView.navigationDelegate = self
        }
        // 方法二 加载路径
        //        let htmlPath = Bundle.main.url(forResource: "index", withExtension: "html")
        //        if let htmlPath = htmlPath{
        //            let request = URLRequest(url: htmlPath)
        //            self.webView.load(request)
        //            self.webView.navigationDelegate = self
        //        }
    }
    // loadHTMLString
    @objc func loadHTMLString(_ sender: AnyObject){
        // 方法一 直接加载 html 字符串
        //        let bundleUrl = NSURL.fileURL(withPath: Bundle.main.bundlePath)
        //        self.webView.loadHTMLString("<html><head><meta charset='utf-8'/><title>测试</title></head><body><h1>测试标题</h1></body></html>", baseURL: bundleUrl)

        // 方法二 把本地文件转成字符串，进行加载
        let htmlPath = Bundle.main.path(forResource: "index2", ofType: "html")
        let bundleUrl = NSURL.fileURL(withPath: Bundle.main.bundlePath)
        do{
            let html = try NSString(contentsOfFile: htmlPath!, encoding: String.Encoding.utf8.rawValue)
            self.webView.loadHTMLString(html as String, baseURL: bundleUrl)
        }catch let err as NSError{
            err.description
        }
    }
    // loadData 方式加载 -- > loadData 已经转换成--> load
    @objc func loadData(_ sender: AnyObject){
        let htmlPath = Bundle.main.path(forResource: "index3", ofType: "html")
        let bundleUrl = NSURL.fileURL(withPath: Bundle.main.bundlePath)

        let htmlData = NSData(contentsOfFile: htmlPath!)
        // NSData 要先转换成 Data 类型
        self.webView.load(htmlData! as Data, mimeType: "text/html", characterEncodingName: "utf-8", baseURL: bundleUrl)

    }
    // loadRequest 加载网络路径 ---> loadRequest 已经改为 load , NSURL --> URL,NSURLRequest -->  URLRequest
    @objc func loadRequest(_ sender: AnyObject){
        let url = URL(string: "https://baidu.com")
        let request = URLRequest(url: url!)
        self.webView.load(request)
        self.webView.navigationDelegate = self
    }
    // 委托协议的监听方法
    func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
        print("开始加载")
    }
    func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
        print("内容开始返回")
    }
    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        print("加载完成")
    }
    func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
        print("加载失败 error:" + error.localizedDescription)
    }
}

上面 有四种方式 加载html 网页，

加载本地 html 的方法 有：

1. buttonHTML
2. loadHTMLString
3. loadData

加载网络路径

  loadRequest

案例中每一种方法都可以加载成功，加载方式大同小异


加载本地文件，会自动去找到文件，如上图 2 个静态文件夹，里面没找到就会寻找外面的静态文件夹。

加载网络资源会报错处理一下就好：https://www.cnblogs.com/bruce-gou/p/10517044.html

以上的方式 文件夹是通过 NEW Group 的方式创建的。
如果是 通过菜单 Add Files to 这种方式创建的 则不可以。这种方式创建的文件夹是蓝色的如图

通过以上方式创建的文件，通过 Bundle.main.path(forResource: "index", ofType: "html")  取不到路径

    @objc func test(_ sender: AnyObject){
        let bundlePath = Bundle.main.bundlePath
        let path = "file://\(bundlePath)/assets/index.html"
        let url = URL(string: path);
        let request = URLRequest(url: url!)
        self.webView.load(request)
    }

这样就可以取到路径值，就可以正常加载