Well, that's not exactly it. The pointer is needed in setOnClickListener to distinguish that specific instance of the listener class from the thousand other possible instances in the machine. You'll find the analogous pointer in C++ based systems, eg.
And note that it need not be "this". One might very well do: MyListenerClass listener = new MyListenerClass(<some args>); someWidget.setOnClickListener(listener); On Jul 18, 4:53 pm, Sam Hobbs <[email protected]> wrote: > I am new to Java, but since Justin says that the this reference is > essentially the same as in C++ and C# I hope my comments are helpful. > > I think one point that was not made clear is that the operating system > (Android, Linux or whatever) is not written in Java but if it was > written in Java it would need to call event handlers in a manner that is > independent of the language. So when Android calls the > setOnClickListener event handler, it does not have a this reference and > could not call the event handler with this even if it knew what this is. > So it is quite common to pass the this as an argument so the event > handler can access the other members of it's class. > > Keith Roberts wrote: > > Hey all, > > > I know that the keyword "this" refers to an instance variable or can > > invoke a constructor, but I don't understand how passing "this" as the > > arg for setOnClickListener () works?Could someone explain? > > > Thanks, > > > keith > > -- > Sam Hobbs > Los Angeles, CA -- You received this message because you are subscribed to the Google Groups "Android Beginners" group. NEW! Try asking and tagging your question on Stack Overflow at http://stackoverflow.com/questions/tagged/android To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-beginners?hl=en
