WebView-java与js的互调

打电话、发邮件（html页面）

需求：html 页面调用打电话、发邮件功能

<a href="tel:1234567890">拨打电话</a>

<a href="mailto:example@example.com">发送邮件</a>

webView.loadUrl("file:///android_asset/demo.html") 
webView.settings.javaScriptEnabled = true
webView.webViewClient = object :WebViewClient(){
            override fun shouldOverrideUrlLoading(
                view: WebView?,
                request: WebResourceRequest?
            ): Boolean {
                val url = request?.url.toString()
                if (url.startsWith("tel:")){
                    val intent = Intent(Intent.ACTION_DIAL , Uri.parse(url))
                    startActivity(intent)
                    return true ;
                }else  if(url.startsWith("mailto:")){
                    val intent = Intent(
                        Intent.ACTION_SENDTO,
                        Uri.parse(url)
                    )
                    startActivity(intent)
                    return true ;
                }
                return super.shouldOverrideUrlLoading(view, request)
            }
        }

Js调Java方法

javascipt调用java的方法

<button onclick="AndroidInterface.showToast('Hello from JavaScript')">调用Java方法</button>

//定义javascript接口类
inner class MyJavaScriptInterface {
        @JavascriptInterface
        fun showToast(message: String?) {
            Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show()
        }
}

//添加
webView.addJavascriptInterface(MyJavaScriptInterface(),"AndroidInterface")

Java调js方法

java层调html定义的javascript方法

<script>
   function javascriptMethodName(parameter) {
        // 获取<h1>元素
        var h1Element = document.querySelector("h1");
        // 修改<h1>元素的内容
        h1Element.textContent = "新的标题: "+parameter;
        return "ok from html5"
    }
</script>

findViewById<Button>(R.id.btn).setOnClickListener{
     val time = System.currentTimeMillis()
     webView.evaluateJavascript("javascriptMethodName($time)" ,object : ValueCallback<String>{ //当html方法结束，会执行的回调函数

          override fun onReceiveValue(value: String?) {
              Toast.makeText(getApplicationContext(), value, Toast.LENGTH_SHORT).show()

          }

   })
}