Build a small Android application that connects to world.openfoodfacts.org HTTP API.

This API provides product information based on barcode number.

In this application, the user should be able to:


• see a product information by using its barcode number;
• see previously searched products while online and offline.

Target SDK : 28 AKA Android Pie (min SDK 19, covering ~95% of Android devices).

As an app user :

1. I should be able to search product information by the barcode number
2. If a product is found, I should be able to see the 
product name, the picture of the products, the ingredients and the 
energy value (kcal) 

3. I should be able to browse a history of the previously 
searched products 

4. I should be able to see the information about a 
product in my history of searches even If I am offline 


This first release will be created by implementing this features step by step:

• Create and configure project
• Add library for barcode scanning and show result on secondary activity
• Add library for HTTP GET operation on API: for simplify the code, the app will save only desired data from JSON
• Add entity model of product and create database
• Save data found from GET operation on DB and show found data on detail activity
• Show saved data on a list / grid on main activity
• Create an UI (icons, launcher icons, activity interfaces, theme)
• Improve / create test

• Add animations
• Add delete function of unwanted product
• Add option to allow manual bar code insertion
• Add placeholder text / images when data is not loaded correctly from server or is missing
• Add more info about products: additives, product quality, manufacturer
• Improve camera activity UI
• Improve tests
• Bug fix

The following is a list of know bug to fix on next release:

• API search is not working on Android 7.0, see this link for more info
• Handle correctly missing internet connection
• Handle correctly product found from another country

The UI of the app is composed by:

• A main activity that show a history of previous research, done with RecyclerView as list (coupled with Android Architecture)
• A detail activity, which is used to show product details
• Each activity has is own fragment
• CardView for a lovely sight and content organization
• A secondary activity used to read the bar code and send results to detail activity

• api : contains API calls, using Retrofit
• barcode : contains Android Vision class which create an overlay showing found bar code
• camera : contains Android Vision class which handle camera and capturing frames for inspecting bar code
• data : contains the repository class, responsible for triggering API requests and saving the response in the database
• db : contains database cache for network data
• model : contains the data model, which is also a table in the Room database
• rawmodel : contains the raw data model used by Retrofit in order to deserialize JSON data returned by API
• ui : contains all classes concerning UI
• util : package containing various data class
• viewmodel : contains all classes designed to store and manage UI-related data

The app uses following patterns:

• Model-View-ViewModel MVVM pattern for the presentation layer.
• Repository pattern, which handle all communications with DAO and search on API.
• Observer pattern.

You will find some code about listed libraries / framework / language:

• Kotlin
• Room
• ViewModel
• LiveData
• DataBinding
• RxJava and RxAndroid with reactivenetwork-rx library
• Glide which will load and cache images from web
• Gson coupled with Retrofit in order to create POJO of data searched on API
• Retrofit HTTP client for network operation
• Mobile Vision API Google official code which provide bar code detection APIs that read and decode a myriad of different bar code types