WebSettings webSettings = mWebView.getSettings();
// 使用默认的缓存策略，cache 没有过期就用 cache
webSettings.setCacheMode(WebSettings.LOAD_DEFAULT);
// 加载网页图片资源
webSettings.setBlockNetworkImage(false);
// 支持 JavaScript 脚本
webSettings.setJavaScriptEnabled(true);
// 支持缩放
webSettings.setSupportZoom(true);
mWebView.setWebViewClient(new WebViewClient() {
    // API 21及之后使用此方法
    @SuppressLint("NewApi")
    @Override
    public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
        if (request != null && request.getUrl() != null && request.getMethod().equalsIgnoreCase("get")) {
            String scheme = request.getUrl().getScheme().trim();
            String url = request.getUrl().toString();
            Log.d(TAG, "url:" + url);
            // HTTPDNS 解析 css 文件的网络请求及图片请求
            if ((scheme.equalsIgnoreCase("http") || scheme.equalsIgnoreCase("https"))
            && (url.contains(".css") || url.endsWith(".png") || url.endsWith(".jpg") || url .endsWith(".gif"))) {
                try {
                    URL oldUrl = new URL(url);
                    URLConnection connection = oldUrl.openConnection();
                    // 获取 HTTPDNS 域名解析结果
                    String ips = MSDKDnsResolver.getInstance().getAddrByName(oldUrl.getHost());
                    String[] ipArr = ips.split(";");
                    if (2 == ipArr.length && !"0".equals(ipArr[0])) { // 通过 HTTPDNS 获取 IP 成功，进行 URL 替换和 HOST 头设置
                        String ip = ipArr[0];
                        String newUrl = url.replaceFirst(oldUrl.getHost(), ip);
                        connection = (HttpURLConnection) new URL(newUrl).openConnection(); // 设置 HTTP 请求头 Host 域名
                        connection.setRequestProperty("Host", oldUrl.getHost());
                    }
                    Log.d(TAG, "contentType:" + connection.getContentType());
                    return new WebResourceResponse("text/css", "UTF-8", connection.getInputStream());
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

    // API 11至 API20使用此方法
    public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
        if (!TextUtils.isEmpty(url) && Uri.parse(url).getScheme() != null) {
            String scheme = Uri.parse(url).getScheme().trim();
            Log.d(TAG, "url:" + url);
            // HTTPDNS 解析 css 文件的网络请求及图片请求
            if ((scheme.equalsIgnoreCase("http") || scheme.equalsIgnoreCase("https"))
            && (url.contains(".css") || url.endsWith(".png") || url.endsWith(".jpg") || url.endsWith(".gif"))) {
                try {
                    URL oldUrl = new URL(url);
                    URLConnection connection = oldUrl.openConnection();
                    // 获取 HTTPDNS 域名解析结果
                    String ips = MSDKDnsResolver.getInstance().getAddrByName(oldUrl.getHost());
                    String[] ipArr = ips.split(";");
                    if (2 == ipArr.length && !"0".equals(ipArr[0])) { // 通过 HTTPDNS 获取 IP 成功，进行 URL 替换和 HOST 头设置
                        String ip = ipArr[0];
                        String newUrl = url.replaceFirst(oldUrl.getHost(), ip);
                        connection = (HttpURLConnection) new URL(newUrl).openConnection(); // 设置 HTTP 请求头 Host 域名
                        connection.setRequestProperty("Host", oldUrl.getHost());
                    }
                    Log.d(TAG, "contentType:" + connection.getContentType());
                    return new WebResourceResponse("text/css", "UTF-8", connection.getInputStream());
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                }
            }
        }
        return null;
    }});
// 加载web资源
mWebView.loadUrl(targetUrl);