I have just read the description of MVC desing pattern and I havesome questions: I am Android developer (junior), and I want to make my code more clear. So, should I use MVC for it? And must every activity has own model? Is there any good tutorial for it? Thank you.
It's already implemented. MVC pattern on Android
you need not to do anything, As Android is prebuilt MVC
MVC is kind of an idea more than a specific way of doing things (like a 1-to-1 relation between activities and models). The idea is to separate the model, view, and controller, so that stuff makes sense.
In Android, more than one activity can refer to a single model (for example, an activity with a list of houses you can search on, an "edit house" activity, and a map that shows them as points in their coordinates). So, to answer your second question: no, they don't need to have their own model.
And yes, you should use MVC, if it makes sense. Just think about your models as a separate entity from the actual application, and your activities as "users" of the models.
On Android, I've found the MVP (Model, View, Presenter) pattern to be a more direct correlation with the overall system architecture. Your activities comprise the Views, which in the MVP setup are responsible for managing their own events and controlling their own appearance. The presenter serves as a facilitator between the model and the view, providing the data when the View requests it. Depending on your needs, the presenters may or may not be a service. As for the View/Model ratio, it really depends on what you're trying to show on your screen at any one point. When android was running on phones only, it made sense to have pretty much a one to one correlation between Activities and your model. Now, the normal case is to have a one to one correlation between your model and your fragments, which your activity then marshalls about by showing the appropriate fragments.
If you want to do MVC, though, again, now that fragments are a tool in the toolbox this is much easier than it once was, especially with well developed event system (such as the one included in RoboGuice) - Think of your fragments as your Views, and your activities as controllers - Ordering your views about, providing them data from the model, and handling transitions to other controllers.
The choice of pattern depends on your needs - if one's application is to be heeavily service driven, MVP is probably a better way to go. If, however, the app is just a thin client over a database, then MVC might be easier. It's all up to you :)
'get started' resource for MVP : http://www.jamespeckham.com/blog/10-11-21/MVP_on_Android.aspx
