Question

Android SDK has an interface in TouchEvent. (android.view.View.OnTouchListener)
I don’t know why the following line fails. (and Eclipse notices error at OnTouchListener)

public class TouchHandler extends OnTouchListener{

And it works if change to:

public interface TouchHandler extends OnTouchListener{

It means that I cannot create a class that extends OnTouchListener. Can somebody explain why?

thanks 🙂

Answer 1

You should use TouchHandler implements OnTouchListener

extending an interface is only possible when defining an interface (ie:extending a contract)
implementing an interface is the java way to have a class provide code for methods of an interface. (ie: defining how the contract is handled)