Landmark Remark

Install Landmark Remark App on your device and enjoy saving short notes of your favourite places in your city. Find your notes easily by searching using a user name or contained text.

Requirements

• As a user (of the application) I can see my current location on a map
• As a user I can save a short note at my current location
• As a user I can see notes that I have saved at the location they were saved on the map
• As a user I can see the location, text, and user-name of notes other users have saved
• As a user I have the ability to search for a note based on contained text or user-name

implicit Requirements

• As a user I can save a short note in any location of the map
• As a user I can save a note only if I have a valid user account and I am authenticated
• As a user I can save a note of a maximum of 280 characters
• As a user I can read the notes by tapping on the markers displayed on the map
• As a user I can create a user account
• As a user I can log in using my user account
• As a user I can enable or deny location permissions of the application
• As a user I can be notified about any error in the app

Project setup

• Clone the repo and open the project in Android Studio
• Get a Google Maps API Key following this steps described in the Google Maps documentation and add it to the google_maps_api.xml file
• This project uses Firebase Cloud Firestore and Email/Password authentication as backend services. To configure this services go to the Firebase Console and create a new projectCreate a new project. Once the project has been created created, enable the Email/Password Sign-in method and create a database with a single collection called Notes. The project will use this collection to store the notes created in the map.
• Finally, download the google-services.json file from Firebase and add it to the project or follow the steps specified in the Firebase documentation

Architecture

The application architecture is based on Clean Architecture. It is composed of one Android module that includes three main layers:

• Presentation: This layer contains the UI elements ( Activities, Fragments, Views, Adapters, etc... ) and the Android ViewModels from the Android Architecture Components. The ViewModel receives events from the Views and proceeds to get the required data which is then turned into view states in the form of Livedata. The Views either listen to or react to directly via Data Binding.
• Domain: This holds the business logic. This layer contains the business models ( entities, Kotlin Data classes ), the contract definition for the Repositories and the business use cases.
• Data: This layer handles the data: Where it comes from and how to get it. This logic will conform to the contracts defined in the domain layer. The Repositories can choose whether the data should be fetched from a local o remote data sources.

Data Flow

On the presentation side the ViewModel will react to a user action or UI event and use use cases to get some data through the repositories. The information traveling from the data layer, through the domain layer and into the ViewModel in the presentation layer is contained in a Result object, which is either a Success or an Error.

Exceptions and errors happening along the way are caught and wrapped into custom Error objects which can be acted upon appropriately.

The communication between layers is done with Kotlin Coroutines in order to perform asynchronous tasks in a structured way.

To get the data from the data sources the system uses one-shot components which means that an action will perform an operation only once, therefore refresh-data operations have to be done manually (eg. press a refresh button). Multiple-values components or Real-time data handling is out of the scope could be implemented using Courtine Flows.

Technology stack

front-end

Android Native Application developed using Android Studio 4.0.1 and Google libraries.

• Kotlin 1.3.72
• Gradle 6.1.1
• minSdkVersion 26
• targetSdkVersion 29

lbraries

Navigation Components
androidx.navigation:navigation-fragment-ktx
androidx.navigation:navigation-ui-ktx
    
Google Maps
com.google.android.gms:play-services-maps

Location
com.google.android.gms:play-services-location

Material Components
com.google.android.material:material

Dependency injection
com.google.dagger:hilt-android

backend

Firebase for Android.

lbraries

Storage
com.google.firebase:firebase-firestore-ktx

User Authentication
com.google.firebase:firebase-auth-ktx:19.3.2

Testing

To run unit tests type in the command line: ./gradlew test

The architecture implemented in this application is based on SOLID principles, therefore, the business rules and the system layers can be unit tested.

The components included as part of the unit test coverage are:

• Presentation layer: Viewmodels and LiveData objects that hold the data that will be displayed in the UI
• Domain layer: Use cases and business logic tests
• Data layer: Repositories and Datasources tests
• Extension functions: Helper classes and extension functions with business logic

Note: Components that are not included as part of the unit test coverage:

• Autogenerated classes by the DI framework and Databinding
• UI and VIew components such us Activities, Fragments and Custom Views
• Third-party libraries

lbraries

testImplementation 'org.mockito:mockito-core:3.3.3'
testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.3.7'
testImplementation 'com.google.truth:truth:1.0.1
testImplementation 'junit:junit:4.13

Design

Based on the Material Components Specification.

Dark/Ligth modes supported.

Accesibility

Based on the Android accesibility Guidelines.

Out of the scope

• Localisation
• Real-time updates
• Note selection from the Search Notes List
• User Location updates
• Error handling depending on the Exception type, at the moment the app uses a DomainError to manage all types of exceptions

Known issues

• In some instances Google Maps MapFragment is extremely laggy on returning from the backstack.