Android WebView and Javascript-Java interaction process

<?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"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
</LinearLayout>

/*from w w  w  . jav  a 2 s .  c  o m*/
//package com.prasanta;

package com.java2s.myapplication3.app;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Handler.Callback;
import android.util.Log;
import android.webkit.WebView;

/**
 * Demonstrates usage of Android WebView and Javascript-Java
 * interaction process.
 *
 * @author prasanta
 *
 */
public class MainActivity extends Activity implements Callback {

    WebView mWebView;
    String TAG = "Prasanta";
    Handler mHandler;
    ProgressDialog dialog;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mHandler = new Handler(this);
        setContentView(initWebView());
    }

    /**
     * Initialize WebView
     * @return
     */
    private WebView initWebView() {
        mWebView = new WebView(this);

        mWebView.getSettings().setJavaScriptEnabled(true);
        mWebView.getSettings().setSupportZoom(false);
        // Scale
        mWebView.setInitialScale(0);

        // Define the JS-Java interaction object
        mWebView.addJavascriptInterface(new JSImp(), "native_java");

        // load content
        mWebView.loadUrl("file:///android_asset/web/index.html");

        return mWebView;
    }

    private class JSImp {

        public String getDataFromJava(final String name){
            // Ask handler to show Dialog Box
            mHandler.sendEmptyMessage(0);

        /*
         * Schedule one Task to Cancel Dialog and Update HTML element
         */
            Timer timer = new Timer();
            TimerTask task = new TimerTask(){
                public void run(){
                    if(dialog != null && dialog.isShowing())
                        dialog.cancel();

                    // Call JS method
              /*
               * Make sure you call this once the respective HTML/JavaScript code loading is over
               */
                    mWebView.loadUrl("javascript:updateMsg('"+ name +" got 750 messages')");
                }
            };

            timer.schedule(task, 2000);

            return name +" - you got 750 messages";
        }

    }

    public boolean handleMessage(Message msg) {
        // Show progress bar
        Log.i(TAG, "Showing progress....");
        dialog = new ProgressDialog(this);
        dialog.setTitle("Please wait...");
        dialog.show();
        return false;
    }
}