Android Reddit Reader

Context

This project is being carried out by Mauricio Guignard for elective "Android Programming: Introduction" of the Faculty of Mathematics, Astronomy, Physics and Computing (FaMAF), UNC, Argentina dictated by Professor Diego Mercado.

Activities Assignment | Step 1

Objectives

• Learn the communication between activities and their lifecycle

Statement

• Download the tag "activities_assignment" from the repository https://github.com/mercadodiego/RedditReader
• Pressing "Sign in or register" should invoke LoginActivity
• Once logged in, the user name should be displayed on the screen

LayoutAssignment | Step 2

Objectives

• Learn the basic principles of Layouts, View and View Groups on Android
• Learn to modify and add graphics and text resources to the application

Statement

• Download the tag "layout_assignment" from the repository https://github.com/mercadodiego/RedditReader
• Add Spanish translation
• Change application name to "Reddit Reader" in English and "Lector de Reddit" in Spanish
• Change application icon to ./images/reddit_icon.png
• Change package name to ar.edu.unc.famaf.redditreader
• Add a subreddit item layout as shown in ./images/screenshot1.jpg

AdaptersAssignment | Step 3

Objectives

• Implement a ListView that gets its content from a custom ArrayAdapter

Statement

• Download the tag "adapters_assignment" from the repository https://github.com/mercadodiego/RedditReader
• The class ar.edu.unc.famaf.redditreader.model.PostModel should represent a Post in Reddit. Add the attributes relating to title, author, creation date, number of comments, image preview / thumbnail, etc. with the corresponding setter / getter
• Implement the method List<PostModel> getTopPosts() of the class ar.edu.unc.famaf.redditreader.backend.Backend. It should always return 5 dummy PostModel instances
• Create a ar.edu.unc.famaf.redditreader.ui.PostAdapter class that extends android.widget.ArrayAdapter and re-implement the necessary methods
• NewsActivityFragment should show a ListView occupying all the space available and must display the contents of each of the posts following the design implemented in the previous activity LayoutAssignment. Keep in mind that the title should always be displayed and the height of each row should be adjusted to allow it
• Implement a ViewHolder in the ar.edu.unc.famaf.redditreader.ui.PostAdapter class to improve the performance of the ListView

ThreadsAssignment | Step 4

Objectives

• Implement an AsyncTask within the ListView to download the thumbnails from Internet

Prerequisites

• Having completed the AdaptersAssignment activity

Statement

• The class ar.edu.unc.famaf.redditreader.ui.PostAdapter should implement an AsyncTask that given an URL previously defined in the ar.edu.unc.famaf.redditreader.model.PostModel class, allows to download the image and displays it in the ImageView representative of the image preview / thumbnail
• An animated android.widget.ProgressBar must be shown while the image is being downloaded

WebServicesAssignment | Step 5

Objectives

• Make a call to a REST service, interpret the returned JSON and display the results on screen.

Prerequisites

• Having completed the ThreadsAssignment activity

Statement

• The class ar.edu.unc.famaf.redditreader.backend.GetTopPostsTask should get the content of the first 50 Reddit's Top posts via HTTP in JSON format, interpret it and return as result a List<PostModel>
• The content must be displayed in the ListView of the NewsActivityFragment class
• When no INTERNET connection is available, an AlertDialog or Toast must be displayed indicating the error
• The JSON interpreter must be defined in a new ar.edu.unc.famaf.redditreader.backend.Parser class and must implement the following input method, internally using an instance of JsonReader that returns an instance of a new class called ar.edu.unc.famaf.redditreader.model.Listing (according to the structure of objects of the Reddit API)

    public Listing readJsonStream(InputStream in) throws IOException {....}

PersistenceAssignment | Step 6

Objectives

• Implement a small SQLite database

Prerequisites

• Having completed the WebServicesAssignment activity

Statement

• The class ar.edu.unc.famaf.redditreader.backend.GetTopPostsTask should implement the following behaviour:

1. Invoke Reddit's REST service to get the 50 first TOP posts
2. Persist the results in an internal database
3. Return the results from the internal database
4. If no internet connection is available, the last results obtained from the internal database must be returned

• The internal database must be implemented in a new class ar.edu.unc.famaf.redditreader.backend.RedditDBHelper that extends SQLiteOpenHelper
• Should only store the last 50 posts. All the others must be deleted
• The thumbnails/preview should also be stored in the internal database as they are downloaded. Remember that they can be stored as a byte array:

   public static byte[] getBytes(Bitmap bitmap)
   {
        ByteArrayOutputStream stream=new ByteArrayOutputStream();
        bitmap.compress(CompressFormat.JPEG,0, stream);
        return stream.toByteArray();
   }
   public static Bitmap getImage(byte[] image)
   {
        return BitmapFactory.decodeByteArray(image, 0, image.length);
   }

Licence

• Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Public License