New to android fragments - looking for a few answers

Question

I'm fairly new to android, and have been working on an app for a few weeks. I want the app to run on handhelds and tablets. I decided to implement fragments after running things on my tablet and am having trouble getting my head around it to get the ball rolling. My app is like most: The first page you see is a menu list of various activities you can navigate to, some of which call other activities. I've read countless tutorials, but still have a few questions, I'm hoping someone can help with. I haven't had any luck finding the answers on the internet.

1) Should the main menu be in a fragment or just remain an activity that calls fragments? (I'm thinking it should be a fragment as well)

2) I've read that the activities are just a portal to the fragment, so in the main menu all of my logic should go in the fragment?

3) Why does eclipse throw a dummy class into the wizard setup? Shouldn't this package just be deleted and the array adapter or whatever be put into the logic of the main menu or do I require another class for a good reason?

4) I also read somewhere that the Main activity must be called Main.java is this true? I don't see why it would be.

I realize these are all probably pretty simple questions to someone that has a grasp on fragments, but I don't! Thanks for any answers Ken

Answer 1

1) If you want different layouts depending on device and/or orientation then yes. Maybe you want the main menu to be located in a pane on the left on a tablet while it's a full screen list on a phone.

2) This is a bit more tricky to answer. It all depends on how you design your application, and there really is not right or wrong here. You could opt for an MVC like approach where you put the actual logic in a controller. You could let your Activity deal with what happens when a menu item is selected. You could use an eventbus (Otto or Guava) to communicate between fragments. It's up to you.

3) Not needed

4) No, you don't have to name it Main.java. I think you may be confusing this with the public static void main(String[] args) entry point of a standard J2SE program?

Answer 2

1) Yes, if you are handling logic and ui, and you are attempting to do your best and want to have a structure that you can easily support multiple screen sizes, your menu should be a fragment.

I think the activity is the mechanism to handle what fragments to display.

So on a phone the first activity just displays the menu fragment and launches a new activity to handle the selection.

While on a tablet you might have the menu fragment on the left side of the screen and do a fragment transition for the right side of the screen upon user selection

2) Your activity still has work to do to coordinate those fragments as my example in 1.

3) You don't need that class

4) You can name anything at all, anything at all. Pay attention to what's specified in your manifest. Your app can even have multiple starting points / icons in the launcher if you specify it as such in the manifest.