Simple example of Button and OnClickListener

Basic example of Button and OnClickListener to handle button click:

package com.example.androidbutton;

import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  Button button1 = (Button)findViewById(R.id.button1);
  button1.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    Toast.makeText(getApplicationContext(), 
      "Button 1 clicked", 
      Toast.LENGTH_LONG).show();
   }});
  
  Button button2 = (Button)findViewById(R.id.button2);
  button2.setOnClickListener(button2OnClickListener);
 }

 OnClickListener button2OnClickListener =
   new OnClickListener(){

    @Override
    public void onClick(View v) {
     Toast.makeText(getApplicationContext(), 
       "Button 2 clicked", 
       Toast.LENGTH_LONG).show();
    }};

}

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="android-er.blogspot.com" />
    
    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button 1"/>
    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button 2"/>

</LinearLayout>

Next:
- Determine event source in event listener