btn_other.setOnClickListener(this);

<Button ...
    android:id="+@id/landButton
    android:onClick = "onClick"/>

public void onClick(View view){
  switch (view.getId()){
   case R.id.landButton: //нажали на кнопку landButtin;
        break;
   }
}

Button landButton = (Button) findViewById(R.id.landButton);
if (landButton != null) {
    // действия с кнопкой
}

@OnClick(R.id.myButton)
public void onClickMyButton(View view) {
  //blah-blah
}

@Optional
@OnClick(R.id.myButton)
public void onClickMyButton(View view) {
  //blah-blah
}