android 中Java和javascript的交互

来源：互联网发布：python案例讲解编辑：程序博客网时间：2024/05/01 14:50

webview提供了接口让javascript访问Java应用程序，WebView.addJavascriptInterface()方法就是实现交互接口的好东西呀！当然也是很危险的！看下面例子：

//main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<EditText
android:id="@+id/txt"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    />
<Button
android:id="@+id/btn"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Send To JavaScript"
    />
<TextView
android:id="@+id/show"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    />
<WebView
android:id="@+id/wv"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    />
</LinearLayout>

//WebJavaScript.java

package com.hl;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class WebJavaScript extends Activity {
private EditText txt;
private WebView wv;
private Button btn;
private Handler h = new Handler();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        txt = (EditText) findViewById(R.id.txt);
        wv = (WebView) findViewById(R.id.wv);
        btn = (Button) findViewById(R.id.btn);

        WebSettings webSettings = wv.getSettings();

        webSettings.setJavaScriptEnabled(true);
        webSettings.setSaveFormData(false);
        webSettings.setSavePassword(false);
        webSettings.setSupportZoom(false);

        wv.addJavascriptInterface(new runJavaScript(), "myjs");
        //myjs是自己定义的，供javascript访问的接口

        String url = "file:///android_asset/android.html";
        wv.loadUrl(url);

        btn.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {
    //调用javascript的函数get4Android(str)
    wv.loadUrl("javascript:get4Android('"+ txt.getText().toString() + "')");
   }
  });
    }
    //The Java object that is bound runs in another thread and not in the thread that it was constructed in.文档的一句话！
    final class runJavaScript{//这个Java 对象是绑定在另一个线程里的，
      public void runOnAndroidJavaScript(final String str){
       h.post(new Runnable(){
    @Override
    public void run() {//这里应该特别注意的
     TextView show = (TextView) findViewById(R.id.show);
          show.setText("This is a message from javascript:"+str);
    }

   });
      }
    }
}

//放在assets文件夹的html文件，android.html

<!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd ">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script language="javascript" type="text/javascript">
function get4Android(str){
document.getElementById("show").innerHTML="This is a message from android:"+str;
}
function send2Android(){
var str = document.getElementById("mess").value;
window.myjs.runOnAndroidJavaScript(str);//调用android的函数
}
</script>
</head>

<body>
<input type="text" id="mess" />
<input type="button" value="Send To Android" onclick="send2Android()"/>
<div id="show"></div>
</body>
</html>
看看效果图吧！

点击查看原图