//declare and define the button

Button button = (Button) findViewById(R.id.button1);

​

​

​

​

//method 1: set the onclick eventlistener with java only

button.setOnClickListener(new OnClickListener() {

  public void onClick(View v) {

    // TODO Auto-generated method stub

  }

 });

/////

​

​

​

​

//method 2:use also layout code (xml)

​

//xml:

//add the following :

android:onClick="functionName"

//to the view you want to add the eventlistener to 

//java: add to the main class

  public void functionName(View v) {

​

}