Question

I am switching gears from iOS to Android and I was wondering about how you re-use your view configuration in Android. In iOS I would typically create a BaseViewController that handled how my app would be “themed” and configured some common view components I wanted to be available everywhere and always (or with conditionals). I would then subclass BaseViewController to suit my view-specific needs. This may not be the ideal way to handle this sort of thing but it worked for me.

In Android I am not sure what I am supposed to do.

There appear to be far more options available for view configuration; I know that you can, like iOS, create views by inflating from XML layout files OR by creating them programatically. I also know that since Java offers inheritance, you could extend the Activity class. So I see a few paths: you could create a base_view.xml file and include it in future layout files, but I see this as being kind of hacky for some reason. You could also create that base_view.xml file, use it in a non-implementable BaseActivity class, and subclass BaseActivity to an implementable and activity-specific version. Or, you could do it programatically in BaseActivity and subclass. I am also vaguely aware of “theme” options in Android that may simplify some of this.

I am almost certain I am going about this in the wrong way and that there are thousands of people who have had to deal with re-using some view configuration before, so all help is appreciated.

Answer 1

There are many different things you may want to re-use. You are not being as specific as we would like to. For instance, these are just some of the things you may want to re-use:

• Styles and themes: If your concern is only how the app looks, then you just have to create a theme and applied to your whole application. You do so by configuring the android:theme attribute in the application tag of your AndroidManifest.xml file.
• Basic layout: as you may already know, android apps usually use actionbar ui pattern. For that kind of things, you can create a BaseActvitiy which handles and configures the actionbar (take a look at the iosched app source code). However, what I recommend in these cases is stick to libraries like ActionBarSherlock which will make things easier and nicer.
• Behavior: for instance, you want to have a search button in all your activities and all it does is calling the startSearch method. In those cases inheritance is encouraged.
• UI components: for instance, you want to reuse some dialogs. In those cases, and most of the OOP cases, composition is encouraged over inheritance. You will learn that for most of those cases you will need to be passing around your activity reference (as a Context). For this case, and in general, I highly recommend you to stick to the support library so that you can use the Fragments API; I know it could be somehow difficult to use at first, but it definitely worths the effort.

If your needs are more specific do not hesitate to comment so that I can try to advice how to proceed.