一共有2中方法：

1. 

  mWebView.loadUrl("file:///android_asset/index.html");

2,.

 private void ProcessWebString() {
        // 載入 asset 檔案
        String tpl = getFromAssets("index.html");
        mWebView.loadDataWithBaseURL(null, tpl, "text/html", "utf-8", null);
    }


    /*
     * 獲取html檔案
     */
    public String getFromAssets(String fileName) {
        try {
            InputStreamReader inputReader = new InputStreamReader(
                    getResources().getAssets().open(fileName));
            BufferedReader bufReader = new BufferedReader(inputReader);
            String line = "";
            String Result = "";
            while ((line = bufReader.readLine()) != null)
                Result += line;
            return Result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }