Android project architecture: database and map?

Issue

My project is a visitor app for a University, that basically displays places and events on a map, and allows the users to interact with one another by making posts with advice/recommendations/questions and so on.

So far I've been trying out bits of code seperately (lists, tabs, the basics), following the android tutorials and trying things for myself. My problem is that I'm not sure how to combine all the bits of code into one project.

I know that I need to make a database, and a map (using OSM rather than google). The database will store information on places, events, and posts that users have made. With co-ordinate information because they need to go on the map. This information is also displayed in seperate tabs - e.g. a list of places.

My problem is that I don't know how this will all fit together. Will I need seperate classes for the database, populating the lists, and displaying on the map? Or can they all be in a single class?

I'm a little hazy on how the classes and activities are going to communicate, too. At the moment I'm thinking the database object is going to get passed to the listviews and mapview, which then take and display some of the information?

Any advice on how to cobble these elements together would be much appreciated. :D

I think I will need to subclass SQLiteOpenHelper for my database, so it'll need to be its own class? I'm thinking of using OSMdroid for the map, which I'm not sure how to do yet. And everything needs to be inside a tabview.

Solution

Welcome to StackOverflow!

Your question is very vague and broad, and likely to get closed as "not a real question" - I suggest you take problems one by one and ask specific questions as you go along and run into problems. Try to think about your problem in these terms: what's the minimal thing I need to get it to do the thing I want. Keep in mind that ANYTHING you want to do is possible, the main question to ask yourself is: what do you want your application to do exactly? Think about the number of different screens (activities), and how they would communicate to each other (when you click XXX, that will lead you to YYY, and so on). One advice: start simple, it's very easy to get buried in too much complexity, especially since it's your first project. It can quickly become very complex, even with a simple concept.

As you didn't specify your level of expertise in coding, it's difficult to give precise advices: but coding an android application is not very different from a "regular" application, with a web or Swing or C# user interface. So I would advise you to learn about OO programming in general, things like composition, inheritance, encapsulation, dependency injection, unit-testing, etc.

Then start writing a base Activity for your main view, write its layout, and add views and graphical elements to it. Then add the listener code for your widgets, that will generate Intents to other Activity.

Then add a DatabaseHelper when you want to save stuff in a database (that can come later, to begin with, you can just "stub" the interactions to a database, by writing what you would save to db on screen using Toast for example).

All objects can be injected into other objects by passing a reference to them, either at construction time or through setters.

Sorry not to be more precise, as I said it's a very vague question.

Answered By - Guillaume