Implement TextToSpeech (TTS) function, with TTS engine selectable.

package com.example.androidtexttospeech;

import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Set;

import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.EngineInfo;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.app.Activity;

public class MainActivity extends Activity implements OnInitListener{
 
 TextView tvDefaultTTS, tvTTSInfo;
 EditText textIn;
 Button buttoSpeak;
 
 Spinner spInstalledEngines;
 TextToSpeech tts;
 List<TextToSpeech.EngineInfo> listInstalledEngines;
 List<String> listInstalledEnginesName;
 String defaultTTS;
 
 private ArrayAdapter<String> adapter;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tvDefaultTTS = (TextView)findViewById(R.id.defaulttts);
  spInstalledEngines = (Spinner)findViewById(R.id.installedengines);
  tvTTSInfo = (TextView)findViewById(R.id.ttsinfo);
  
  tts = new TextToSpeech(this, this);
  listInstalledEngines = tts.getEngines();
  listInstalledEnginesName = new ArrayList<String>();

        for(int i = 0; i < listInstalledEngines.size(); i++){
         listInstalledEnginesName.add(listInstalledEngines.get(i).label);
        }
        
        adapter = new ArrayAdapter<String>(
    this, android.R.layout.simple_spinner_item, listInstalledEnginesName);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spInstalledEngines.setAdapter(adapter);
  
        defaultTTS = tts.getDefaultEngine();
        tvDefaultTTS.setText("Default TTS Engine: " + defaultTTS);
        
        spInstalledEngines.setOnItemSelectedListener(myOnItemSelectedListener);
        
        textIn = (EditText)findViewById(R.id.textin);
        textIn.setText("Android Coding"); //pre-set text
     buttoSpeak = (Button)findViewById(R.id.speak);
     buttoSpeak.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    String textToBeSpeech = textIn.getText().toString();
       tts.speak(textToBeSpeech, TextToSpeech.QUEUE_ADD, null);
    
   }});
     
 }
 
 OnItemSelectedListener myOnItemSelectedListener
 = new OnItemSelectedListener(){

  @Override
  public void onItemSelected(AdapterView<?> parent, View iew, int position,
    long id) {
   
   //shutdown old tts
   if(tts != null){
    tts.shutdown();
   }
   
   //switch to new tts
   EngineInfo selectedEngineInfo = listInstalledEngines.get(position);
   String engine = selectedEngineInfo.name;
   tts = new TextToSpeech(MainActivity.this, MainActivity.this, engine);
   
  }

  @Override
  public void onNothingSelected(AdapterView<?> arg0) {
   // TODO Auto-generated method stub
   
  }};
 
 private void updateTTSInfo(){
  
  String info = "";
  
  Locale locale = tts.getLanguage();
  
  if(locale != null){
   info += "Country: " + locale.getDisplayCountry() + "\n"
     + "Language: " + locale.getDisplayLanguage() + "\n";
   
   Set<String> feature = tts.getFeatures(locale);
   
   String[] featureArray = new String[feature.size()];
   feature.toArray(featureArray);
   for(int i = 0; i < featureArray.length; i++){
    info += "feature : " + featureArray[i] + "\n";
   }
  }
  
  tvTTSInfo.setText(info);
 }

 @Override
 public void onInit(int status) {
  updateTTSInfo();
 }

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

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/hello_world" />
    <TextView
        android:id="@+id/defaulttts"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    <Spinner 
        android:id="@+id/installedengines"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <EditText
        android:id="@+id/textin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <Button
        android:id="@+id/speak"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Speak"/>
    <TextView
        android:id="@+id/ttsinfo"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    
</LinearLayout>