Associate two image

I wanted to create a app that when clicking on an image changed its image and waited to click on another image. If the two images were equal (with the same value) activate a button that gave the possibility to move to another Layout.

I only have the code to change the image.

botao.setOnClickListener(new View.OnClickListener() {

   @Override
   public void onClick(View v) {         
    if( ????????? ) 
       botao.setBackgroundResource(R.drawable.preto);                
    else
       botao.setBackgroundResource(R.drawable.verde);

}