title: In what situation are listener parameters mandatory?
body: <p>I wrote two different listeners for my button:</p>
  
  <pre><code>myButton.setOnClickListener{myOnClick()}
  myButton.setOnKeyListener{myOnKeyListener()}
  </code></pre>
  
  <p>The first one is OK for the compiler. But second one gives an error. It says <strong>Expected 3 parameters of types View!, Int, KeyEvent!</strong></p>
  
  <p>Considering that these are the listeners in the View class:</p>
  
  <pre><code>public interface OnClickListener {
       void onClick(View v);
  }
  
  public interface OnKeyListener {
       boolean onKey(View v, int keyCode, KeyEvent event);
  }
  </code></pre>
  
  <p>Any idea about why is asking me for the parameters in one situation but not in the other?</p>