This Day In History Jetpack Compose App - Saving Onboarded Status

Objective:

Build UserPreferences API and connect

Components built

We will add the following components:

• UserPreferencesRepository: User Preferences API based on Preferences Data Store.
• SettingsViewModelFactory:

Code

User Preferences API

Add UserPreferencesRepository class to the com.coroutines.thisdayinhistory.preferences package in the app module.

package com.coroutines.thisdayinhistory.preferences

import androidx.datastore.core.DataStore
import androidx.datastore.preferences.core.Preferences
import com.coroutines.common.preferences.getEnum
import com.coroutines.common.preferences.setEnum
import com.coroutines.data.models.LangEnum
import com.coroutines.data.models.OnboardingStatusEnum
import com.coroutines.thisdayinhistory.ui.theme.ThisDayInHistoryThemeEnum
import kotlinx.coroutines.flow.Flow


class UserPreferencesRepository constructor(
    private val dataStore: DataStore<Preferences>
) {
    fun getLanguagePreference(): Flow<LangEnum> {
        return dataStore.getEnum<LangEnum>()
    }
    fun getThemePreference(): Flow<ThisDayInHistoryThemeEnum> {
        return dataStore.getEnum<ThisDayInHistoryThemeEnum>()
    }

    fun getOnboardedStatus(): Flow<OnboardingStatusEnum>{
        return dataStore.getEnum<OnboardingStatusEnum>()
    }

    suspend fun setLanguagePreference(langEnum: LangEnum){
        dataStore.setEnum(langEnum)
    }

    suspend fun setThemePreference(historyCatThemeEnum: ThisDayInHistoryThemeEnum){
        dataStore.setEnum(historyCatThemeEnum)
    }

    suspend fun setOnboarded(){
        dataStore.setEnum(OnboardingStatusEnum.Onboarded)
    }
}

SettingsViewModelFactory

Add SettingsViewModelFactory class to the SettingsViewModel.kt file in the com.coroutines.thisdayinhistory.ui.viewmodels package in the app module. Until we introduce Hilt for dependency injection (to do later), we will need this custom view model factory because it expects UserPreferencesRepository passed to integratingin the constructor.

class SettingsViewModelFactory(private val userPreferencesRepository: UserPreferencesRepository) : ViewModelProvider.Factory {@Suppress("UNCHECKED_CAST")
override fun  create(modelClass: Class): T {
    return SettingsViewModel(userPreferencesRepository) as T
    }
}

runUi

Update runUi function in the activity in the app module to create an instance of Preferences Data Store and pass it to SettingsViewModelFactory to create a SettingsViewModel.

package com.coroutines.thisdayinhistory

private fun runUi() = setContent {

        val prefStore = PreferenceDataStoreFactory.create(
            corruptionHandler = ReplaceFileCorruptionHandler(
                produceNewData = { emptyPreferences() }
            ),
            scope = CoroutineScope(Dispatchers.IO + SupervisorJob()),
            produceFile = { application.applicationContext.preferencesDataStoreFile("USER_PREF") }
        )
        val userPreferencesRepository = UserPreferencesRepository(prefStore)
        val settingsViewModel : ISettingsViewModel  by viewModels { SettingsViewModelFactory (userPreferencesRepository) }
        val deviceLanguage = getDeviceLanguage()
        settingsViewModel.setDeviceLanguage(deviceLanguage)

        val appConfigState by settingsViewModel.appConfigurationState.collectAsStateWithLifecycle()


        when (!appConfigState.isLoading) {
            true ->
                { }//load animation
            false -> {
                if (deviceLanguage != appConfigState.appLanguage.langId) {
                    setPerAppLanguage(appConfigState)
                }

                isStatePendingRestore = false

                MainContent(settingsViewModel, appConfigState)
            }
        }
    }