本文详细介绍了一种在Android环境中，如何使JavaScript能够调用Java方法的技术方案。具体包括使用WebView加载本地HTML文件，通过addJavascriptInterface将Java对象暴露给JavaScript，以及在JavaScript中调用这些方法的过程。
转载自品略图书馆 http://www.pinlue.com/article/2020/06/0300/1110672083746.html
ajax调用java后台的方法,其实是通过url链接来访问。下面是小编为大家带来一篇ajax调用java方法，希望对大家有所帮助。
android js调用java方法(一)
[java] view plaincopypublic class JsInterface {
/*interface for javascript to invokes*/
public interface wvClientClickListener {
public void wvHasClickEnvent();
}
private wvClientClickListener wvEnventPro = null;
public void setWvClientClickListener(wvClientClickListener listener) {
wvEnventPro = listener;
}
public void javaFunction() {
if(wvEnventPro != null)
wvEnventPro.wvHasClickEnvent();
}
}
/*Js2JavaActivity.JAVA*/
/*程序入口*/
[java] view plaincopypublic class Js2JavaActivity extends Activity{
private Button btn_show,btn_hide;
private WebView wv;
private JsInterface JSInterface2 = new JsInterface();
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.js2java);
btn_show = (Button)findViewById(R.id.btn_java2js_show);
btn_hide = (Button)findViewById(R.id.btn_java2js_hide);
wv = (WebView)findViewById(R.id.wv_js2java);
wv.getSettings().setJavaScriptEnabled(true);
wv.addJavascriptInterface(JSInterface2,"JSInterface2");
wv.setWebViewClient(new webviewClient());
wv.loadUrl("file:///android_asset/index.html");
}
class webviewClient extends WebViewClient {
@Override
public void onPageFinished(WebView view, String url) {
// TODO Auto-generated method stub
super.onPageFinished(view, url);
btn_show.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(getBaseContext(), "You click show button", 1000).show();
wv.loadUrl(String.format("javascript：java2js(0)"));//这里是java端调用webview的JS
}
});
btn_hide.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(getBaseContext(), "You click hide button", 1000).show();
wv.loadUrl(String.format("javascript：java2js(1)"));//这里是java端调用webview的JS
}
});
JSInterface2.setWvClientClickListener(new webviewClick());//这里就是js调用java端的具体实现
}
}
class webviewClick implements wvClientClickListener {
@Override
public void wvHasClickEnvent() {
// TODO Auto-generated method stub
Toast.makeText(getBaseContext(), "link be on click", 1000).show();
}
}
}
android js调用java方法(二)
JavaJsDemo.java
package com.demo.android.JavaJsDemo;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebView;
import java.util.ArrayList;
import java.util.List;
public class JavaJsDemo extends Activity {
/** Called when the activity is first created. */
private WebView web;
public List<String> list;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initData();
setContentView(R.layout.main);
web = (WebView)this.findViewById(R.id.webview);
//开启javascript设置
web.getSettings().setJavaScriptEnabled(true);
//把RIAExample的一个实例添加到js的全局对象window中
//这样就可以使用window.javatojs来调用它的方法
web.addJavascriptInterface(this, "javatojs");
//加载网页
web.loadUrl("file:///android_asset/index.html");
}
void initData(){
list=new ArrayList<String>();
for(int i=0;i<5;i++){
list.add("我是List中的第"+(i+1)+"行");
}
}
/**
* 该方法将在js脚本中，通过window.javatojs.....()进行调用
* @return
*/
public Object getObject(int index){
return list.get(index);
}
public int getSize(){
return list.size();
}
public void Callfunction(){
web.loadUrl("javascript： GetList()");
}
}
index.html
DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "xxx.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>demotitle>
<script language="javascript">
function GetList(){
var i=window.javatojs.getSize();
for(var n=0;n<i;n++){
var jsdata= window.javatojs.getObject(n);//拿到activity里面的属性javadata
var datalistdiv = document.getElementById("datalist"); //得到页面的div
pnode = document.createElement("p");//创建一个p标签，再建个textnode
tnode = document.createTextNode(jsdata);
pnode.appendChild(tnode);//p中加入数据
datalistdiv.appendChild(pnode);//div中键入新的p
}
}
script>
head>
<body onload="javascript：window.javatojs.Callfunction()">//调用java方法
<div id = "datalist">
this is a demo
div>
body>
html>
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