Home/ Questions/Q 6955083
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-27T14:41:26+00:00

I’m a relatively experienced .NET/iOS developer taking first steps in Android development – to

  • 0

I’m a relatively experienced .NET/iOS developer taking first steps in Android development – to help me avoid going down the wrong path I’d be grateful for some guidance:

Essentially, I have an app that displays locations on a map/list. As the user scrolls around the map, the locations are fetched from a JSON web service. A location can be tapped, at which point another JSON web service is called to retrieve live information for that location. The live info is then displayed.

So, having read the various ‘getting started’ Android docs, I would imagine I need:

  1. An Activity to display the main map view of the locations
  2. A second Activity to display the list view? These seems odd since I get the impression that each Activity has to be an entire screen of the app. I’d like to persist the other UI elements. (e.g. button to switch views, button for settings etc) Is this possible?
  3. A Service (or IntentService?) to retrieve the locations from the web. How should it let the Activity and ContentProvider know when new locations have been retrieved – via Broadcasts or should they bind to it?
  4. A ContentProvider, to cache and persist my locations. Perhaps the content provider should broadcast to the activities when new data is available to display?

Your help would be very much appreciated, since I feel a little lost!

Carlos

PS: I’ll be developing with Mono for Android, unless enough people advise against

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    An Activity to display the main map view of the locations

    Yes

    A second Activity to display the list view? These seems odd since I
    get the impression that each Activity has to be an entire screen of
    the app. I’d like to persist the other UI elements. (e.g. button to
    switch views, button for settings etc) Is this possible?

    Not necessarily so. Take a look at the Fragments API. It allows you to switch only parts of your UI. It was introduced in Android 3.0, but there exists an official backport of it, so that you can also use it in previous Android versions.

    With it, you can put your buttons into the activity, the map in one fragment and the list in another, and then just switch the map with list while retaining the buttons.

    A Service (or IntentService?) to retrieve the locations from the web.
    How should it let the Activity and ContentProvider know when new
    locations have been retrieved – via Broadcasts or should they bind to
    it?

    I would strongly advice against this. You should use a service if you have long-lasting downloads in the background, like downloading a file or something. Short term JSON requests can and should be handled in the UI process. Use AsyncTask or an Executor for that. There has been advice by Google to put almost all of your requests into a service, but believe me, it’s bull.

    A ContentProvider, to cache and persist my locations. Perhaps the
    content provider should broadcast to the activities when new data is
    available to display?

    Not required. You only really need a ContentProvider if you plan to make your content accessible to other Applications or the System. For HTTP caching, you can directly access the database/filesystem, or better yet, use the Apache HTTP Client Cache. Works well if you use the already embedded Apache HTTP Client, which you should.

    • 0