现在的 APP，Android 与 H5 混合开发已很常见。当 Android 通过 WebView 加载 H5 页面，且需要向其传参时，可以用 loaclstorage 来实现。代码如下：
WebView 先要设置如下属性：

 webView.getSettings().setDomStorageEnabled(true);
        webView.getSettings().setAppCacheMaxSize(1024*1024*8);
        String appCachePath = getApplicationContext().getCacheDir().getAbsolutePath();
        webView.getSettings().setAppCachePath(appCachePath);
        webView.getSettings().setAllowFileAccess(true);
        webView.getSettings().setAppCacheEnabled(true);
        JavaScriptInterface jsInterface = new JavaScriptInterface(this);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.addJavascriptInterface(jsInterface, "JSInterface");

然后，传递参数：

   webView.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageFinished(WebView view, String url) {
               String key = "hello";
               String val = "world";
               if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
                   webView.evaluateJavascript("localStorage.setItem('"+ key +"','"+ val +"');", null);
               } else {
                   webView.loadUrl("javascript:localStorage.setItem('"+ key +"','"+ val +"');");
               }
            }
   });

JavaScriptInterface 部分的代码如下：

 public class JavaScriptInterface {
        private Activity activity;

        public JavaScriptInterface(Activity activiy) {
            this.activity = activiy;
        }

        public string getData(String someParameter){
           //also you can return json data as string  and at client side do JSON.parse
           if (someParameter == "transmitData" && this.activity.data) {
                return this.activity.data;
           }else{
                return null;
           }
        }
    }

Js 部分的代码如下：

<script>
  function ready() {
     
     
        var data = window.JSInterface.getData("transmitData");
        localStorage.put("transmitData", data)
  };

  document.addEventListener("DOMContentLoaded", ready);
</script>