Extend MapActivity and another class: avoid multiple inheritance

Question

I would have a class hierarchy like in photo.

Usually in this case it's usefull pattern Decorator in Java, but with MapActivity is not possible, how can i do?

Valid XHTML http://dl.dropbox.com/u/278026/View.png

CommonsWare · Accepted Answer · 2011-04-27 20:49:07Z

2

You cannot "do". As you say, it is impossible in Java.

You can switch to composition instead of inheritance, and move the logic from AbstractMyActivity into something that a MapActivity can also hold onto.

answered Apr 27, 2011 at 20:49

CommonsWare

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3 Comments

Wroclai Over a year ago

Composition is the way to go here, thumbs up!

mardvd Over a year ago

Yes, but i cannot create a Composite class AbstractMapActivity where the component is MapActivity, because i cannot use MapView inside a class AbstractMapActivity that doesn't extends MapActivity

CommonsWare Over a year ago

@Mark: I recommend that you start by learning what object oriented programming is: en.wikipedia.org/wiki/Object-oriented_programming Then, I recommend that you learn what composition is: en.wikipedia.org/wiki/Composite_Pattern Now, I will admit that composition is not ideal here. I wish Java had mixins like Ruby does. But you are clearly confusing composition with abstraction, which are not related.

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