AOskari / Parliament-Today

An Android application used for reviewing Members of the Finnish Parliament.

Parliament-Today

This project implements the Android MVVM and Single-Activity architecture, uses a SQLite Database (Room) for data storage, Retrofit and Moshi for fetching and parsing JSON data into data class objects. Work Manager is used for regular updates for the SQLite Database.

This is an Android application, which fetches Member of Parliament data from https://avoindata.eduskunta.fi/ and stores the data into a SQLite database. The user is able to search the database by giving an input to a SearchView. In addition, the found MP's can be filtered by party and age. Specific data of the MP can be viewed by clicking the MP's name. The user can also create reviews for the chosen MP.

Fragments

The MainActivity contains a FragmentContainerView which is navigated according to the navigation component.

// Navigation to another Fragment.

val action = MemberFragmentDirections.actionMemberFragmentToMemberReviewFragment(memberViewModel.member)
findNavController().navigate(action)

ViewModel

ViewModels are used for storing data displayed in the Views. As ViewModels are lifecycle-aware, data displayed in the Views survive configuration changes.

// Instantiation of a ViewModel in a Fragment class.

memberListViewModelFactory = MemberListViewModelFactory((activity?.application as MPApplication).memberRepository,
            (activity?.application as MPApplication).settingsRepository)
memberListViewModel = ViewModelProvider(this, memberListViewModelFactory).get(MemberListViewModel::class.java)

SQLite Database

The database is implemented using Room. DAOs (Data Access Object) are used for accessing and modifying data in the database tables.

// Creation of the database.

@Volatile
private var INSTANCE: MemberDatabase? = null

// Returns an instance of the MemberDatabase if it is not null.
// Otherwise, create a new instance and return it.
fun getDatabase(context: Context, scope: CoroutineScope): MemberDatabase {
    return INSTANCE ?: synchronized(this) {
        val instance = Room.databaseBuilder(
            context.applicationContext,
            MemberDatabase::class.java,
            "member_database"
        )
            .addCallback(MemberDatabaseCallback(scope))
            .build()
        INSTANCE = instance
        instance
    }
}

DAO

Data Access Objects (DAO) are used for accessing and modifying the database.

// A function in the MemberDao interface, which returns a list of Members from the database wrapped in a LiveData object.
// The parameters are used for querying the wanted members.

@Query("SELECT * FROM member_table WHERE (first || ' ' || last) LIKE :param AND party IN (:parties) AND age >= :minAge AND age <= :maxAge")
fun getMembers(param: String, parties: List<String>, minAge: Int, maxAge: Int): LiveData<List<Member>>

WorkManager

A WorkManager is applied to the MainActivity for regular updates to the SQLite database.

// Applying a periodic work request to the WorkManager, which updates the database once a day.

val workRequest = PeriodicWorkRequest.Builder(DatabaseUpdateWorker::class.java, 1, TimeUnit.DAYS).build()
WorkManager.getInstance(applicationContext)
    .enqueueUniquePeriodicWork("updateDB", ExistingPeriodicWorkPolicy.KEEP, workRequest)