android WebView (4) Interacting with html_html/css_WEB-ITnose

How WebView interacts with html
Many times WebView needs to interact with html, either by controlling page activities through Java code, or by triggering Java code through js. WebView provides a mechanism.

First, let’s take a look at the html code we need to interact with:

      <title>MyHtml.html</title>               <br>    <br>大家晚上好    <br>    <br>大家晚上好    <br>    <br>大家晚上好    <br>  <input type="button" value="测试" onclick="javascript:window.handler.show(document.body.innerHTML);">  

Simple html code, three lines of text, and one button. document.body.innerHTML is to get the content in the body node in html.
Then we load it in and enable js:

	webView.loadUrl("file:///android_asset/MyHtml.html");	webView.getSettings().setJavaScriptEnabled(true);			webView.setWebViewClient(new WebViewClient() {		@Override		public void onPageFinished(WebView view, String url) {			Toast.makeText(WebViewActivity.this, "网页加载完成", 0).show();			view.loadUrl("javascript:window.handler.show(document.body.innerHTML);");			super.onPageFinished(view, url);		}	});

The click event of the button in the above html uses an excuse: window.handler. To use this excuse, we need to define it first:

	class Handler {		public void show(String data) {			new AlertDialog.Builder(WebViewActivity.this).setMessage(data).create().show();		}	}

The function public void show(String data) is provided by this excuse, and has been called by the above html and Java code. But how does WebView know that there is such an excuse to call
? The answer is as follows:

webView.addJavascriptInterface(new Handler(), "handler");

This sentence is used to bind the interface.

The running results are as follows: