1. 确认自定义的字体文件(.ttf或.otf)已放置在res/font目录中。
2. 创建一个自定义的WebViewClient并覆盖shouldInterceptRequest方法，用来拦截请求自定义字体的URL。 示例代码：

WebView myWebView = findViewById(R.id.myWebView);
myWebView.setWebViewClient(new WebViewClient() {
   @Nullable
   @Override
   public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
       String url = request.getUrl().toString();
       if (url.contains("file:///android_res/font/")) {
           try {
               InputStream inputStream = getApplicationContext().getAssets().open("font.ttf"); // 替换为自己想使用的字体文件
               WebResourceResponse response = new WebResourceResponse("application/x-font-ttf", "UTF-8", inputStream);
               return response;
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
       return super.shouldInterceptRequest(view, request);
   }
});

3. 在WebSettings中启用字体支持。

WebSettings webSettings = myWebView.getSettings();
webSettings.setAllowFileAccess(true);
webSettings.setLoadsImagesAutomatically(true);
webSettings.setJavaScriptEnabled(true);
webSettings.setAllowUniversalAccessFromFileURLs(true);