findViewById(R.id.myButton).setOnClickListener(new View.OnClickListener() {   
    public void onClick(View v) {   
        // Do stuff   
    }   
});

View.OnClickListener handler = View.OnClickListener() {   
    public void onClick(View v) {   
        switch (v.getId()) {   
            case R.id.Button01: // doStuff   
                break;   
            case R.id.Button02: // doStuff   
                break;   
        }   
    }   
}   

findViewById(R.id.myButton).setOnClickListener(handler);   
findViewById(R.id.myOtherButton).setOnClickListener(handler); 

<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"  
    />  
<Button    
    android:text="Button01"    
    android:id="@+id/Button01"    
    android:layout_width="wrap_content"    
    android:layout_height="wrap_content"  
    android:onClick="myClickHandler01"  
    />  
<Button    
    android:text="Button02"    
    android:id="@+id/Button02"    
    android:layout_width="wrap_content"    
    android:layout_height="wrap_content"  
    android:onClick="myClickHandler02"  
    />  
<TextView     
    android:layout_width="fill_parent"    
    android:layout_height="wrap_content"    
    android:text="@string/hello"  
    />  
</LinearLayout> 

package com.ray.test;   

import android.app.Activity;   
import android.os.Bundle;   
import android.view.View;   

public class TestOnClickListener extends Activity {   

    @Override  
    public void onCreate(Bundle savedInstanceState) {   
        super.onCreate(savedInstanceState);   
        setContentView(R.layout.main);   

  
    }   
    public void myClickHandler01(View target){   
        setTitle("myClickHandler01");   
    }   
    public void myClickHandler02(View target){   
        setTitle("myClickHandler02");   
    }   
} 

package com.ray.test;   

import android.app.Activity;   
import android.os.Bundle;   
import android.view.View;   

public class TestOnClickListener extends Activity {   

    @Override  
    public void onCreate(Bundle savedInstanceState) {   
        super.onCreate(savedInstanceState);   
        setContentView(R.layout.main);   
    }   
    public void myClickHandler(View target){   
         switch (target.getId()) {   
         case R.id.Button01:    
             setTitle("myClickHandler01");   
             break;   
         case R.id.Button02:    
             setTitle("myClickHandler02");   
             break;   
         }   
    }   
}