Button btn1 = (Button)findViewById(R.id.btn1);
btn1.setOnClickLlistener(new OnClickListener() {
    public void onClick(View v) {
        // Button 1 Command
    }
});

Button btn2 = (Button)findViewById(R.id.btn2);
btn2.setOnClickLlistener(new OnClickListener() {
    public void onClick(View v) {
        // Button 2 Command
    }
});