Implement Android's Text to speech function

package com.AndroidTTS;

import android.app.Activity;
import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class AndroidTTS extends Activity implements OnInitListener{
 
    TextToSpeech tts;
    EditText textIn;
    Button buttonSpeech;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        tts = new TextToSpeech(this, this);
        
        textIn = (EditText)findViewById(R.id.textin);
        buttonSpeech = (Button)findViewById(R.id.speech);
        
        buttonSpeech.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    String textToBeSpeech = textIn.getText().toString();
    tts.speak(textToBeSpeech, TextToSpeech.QUEUE_ADD, null);
   }});
    }

 @Override
 public void onInit(int arg0) {
  // TODO Auto-generated method stub
  //Make sure the Text-To-Speech engine is fully loaded
  //It can be configured and used
  buttonSpeech.setEnabled(true);
 }

 @Override
 protected void onDestroy() {
  // TODO Auto-generated method stub
  super.onDestroy();
  tts.shutdown();
 }
}

<?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"
    />
<EditText
    android:id="@+id/textin"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
<Button
    android:id="@+id/speech"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Speech"
    android:enabled="false"
    />
</LinearLayout>