Webview里面的js如何访问的后台

Android代码

package com.example.sss.helloworld;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        WebView mWebView = (WebView) findViewById(R.id.webview);
        WebSettings webSettings = mWebView.getSettings();
        //允许chrome://inspect调试
        WebView.setWebContentsDebuggingEnabled(true);
        webSettings.setJavaScriptEnabled(true);
        mWebView.loadUrl("file:///android_asset/demo.html");
    }
}

node server.js

var http = require('http');
var URL = require('url');
http.createServer(function (req, res) {
    res.writeHead(200, {
        'Content-Type': 'application/json',
        "access-control-allow-origin": "*",
    });
    res.end((parseInt(Math.random()*100)+""));
}).listen(8080);

console.log('Server running on port 8080.');

demo.html

    
    


Load Text

这种常见的混合模式App开发中，js并不能访问到后台。那么到底是怎么通信的呢。答案：代理。