Migrate from SharedPreferences to DataStore

app/build.gradle.kts

@@ -156,8 +156,9 @@ dependencies {
     implementation(Dependencies.Support.lifecycleCompiler)
     coreLibraryDesugaring(Dependencies.Support.desugarLibs)
 
+    implementation(Dependencies.Support.datastore)
+
     implementation(Dependencies.Support.vectordrawable)
-    implementation(Dependencies.Support.preference)
 
     // Compose
     implementation(Dependencies.Compose.animation)

app/src/main/kotlin/app/futured/androidprojecttemplate/data/persistence/JsonPersistence.kt

@@ -0,0 +1,104 @@
+package app.futured.androidprojecttemplate.data.persistence
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.firstOrNull
+import kotlinx.coroutines.flow.map
+import kotlinx.serialization.SerializationException
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import timber.log.Timber
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * [DataStore]-backed Persistence which allows storage and observing of complex JSON objects.
+ * Uses [kotlinx.serialization] to serialize and deserialize objects into Strings.
+ */
+@Singleton
+class JsonPersistence @Inject constructor(
+    val dataStore: DataStore<Preferences>,
+    val json: Json,
+) {
+
+    /**
+     * Saves provided [value] in persistence under provided [key].
+     */
+    suspend inline fun <reified T : Any> save(
+        key: Preferences.Key<String>,
+        value: T,
+    ) {
+        dataStore.edit { preferences -> preferences[key] = json.encodeToString<T>(value) }
+    }
+
+    /**
+     * Returns persisted object with provided [key].
+     *
+     * @return Persisted object, or `null` if does not exist.
+     * @throws [SerializationException] if object could not be deserialized as [T].
+     */
+    suspend inline fun <reified T : Any> get(key: Preferences.Key<String>): T? =
+        dataStore.data.firstOrNull()
+            ?.let { preferences -> preferences[key] }
+            ?.let { jsonString ->
+                json.decodeFromString<T>(jsonString)
+            }
+
+    /**
+     * Returns a [Flow] of persisted objects with provided [key].
+     *
+     * @return [Flow] of objects. Values in [Flow] can be `null` if not found in persistence.
+     * @throws [SerializationException] if object could not be deserialized as [T].
+     */
+    inline fun <reified T : Any> observe(key: Preferences.Key<String>): Flow<T?> =
+        dataStore.data
+            .map { preferences -> preferences[key] }
+            .map { jsonString ->
+                jsonString?.let { json.decodeFromString(jsonString) }
+            }
+
+    /**
+     * Removes persisted object with provided [key].
+     */
+    suspend fun delete(key: Preferences.Key<String>) = dataStore.edit { preferences -> preferences.remove(key) }
+
+    /**
+     * Returns persisted object with provided [key], catching any [SerializationException]s and mapping them to `null`.
+     *
+     * @return Persisted object, or `null` if does not exist or object cannot be deserialized as [T].
+     */
+    suspend inline fun <reified T : Any> getCatching(key: Preferences.Key<String>): T? =
+        runCatching { get<T>(key) }
+            .recoverCatching { error ->
+                if (error is SerializationException) {
+                    Timber.tag("JsonPersistence").e(error, "Unable to deserialize property with key '${key.name}'")
+                    null
+                } else {
+                    throw error
+                }
+            }
+            .getOrThrow()
+
+    /**
+     * Returns a [Flow] of persisted objects with provided [key], catching any [SerializationException]s that might occur
+     * and mapping them to `null` values.
+     *
+     * @return [Flow] of objects. Values in [Flow] can be `null` if not found in persistence or cannot be deserialized as [T].
+     */
+    inline fun <reified T : Any> observeCatching(key: Preferences.Key<String>): Flow<T?> =
+        dataStore.data
+            .map { preferences -> preferences[key] }
+            .map { jsonString ->
+                runCatching { jsonString?.let { json.decodeFromString<T>(jsonString) } }
+                    .recoverCatching { error ->
+                        if (error is SerializationException) {
+                            Timber.tag("JsonPersistence").e(error, "Unable to deserialize property with key '${key.name}'")
+                            null
+                        } else {
+                            null
+                        }
+                    }.getOrThrow()
+            }
+}

app/src/main/kotlin/app/futured/androidprojecttemplate/data/persistence/PrimitivePersistence.kt

@@ -0,0 +1,35 @@
+package app.futured.androidprojecttemplate.data.persistence
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.firstOrNull
+import kotlinx.coroutines.flow.mapNotNull
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * [DataStore]-backed Persistence which allows storage and observing of persisted entities.
+ */
+@Singleton
+class PrimitivePersistence @Inject constructor(
+    private val dataStore: DataStore<Preferences>,
+) {
+
+    suspend fun <T : Any> get(key: Preferences.Key<T>): T? = dataStore.data.firstOrNull()?.run {
+        this[key]
+    }
+
+    fun <T : Any> observe(key: Preferences.Key<T>): Flow<T> = dataStore.data.mapNotNull {
+        it[key]
+    }
+
+    suspend fun <T : Any> save(key: Preferences.Key<T>, value: T) {
+        dataStore.edit { it[key] = value }
+    }
+
+    suspend fun delete(key: Preferences.Key<*>) = dataStore.edit {
+        it.remove(key)
+    }
+}

app/src/main/kotlin/app/futured/androidprojecttemplate/injection/modules/ApplicationModule.kt

@@ -2,7 +2,10 @@ package app.futured.androidprojecttemplate.injection.modules
 
 import android.content.Context
 import android.content.res.Resources
-import androidx.preference.PreferenceManager
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.preferencesDataStore
+import app.futured.androidprojecttemplate.tools.Constants
 import app.futured.androidprojecttemplate.tools.serialization.ZonedDateTimeSerializer
 import dagger.Module
 import dagger.Provides
@@ -16,6 +19,9 @@ import kotlinx.serialization.modules.SerializersModule
 @Module
 @InstallIn(SingletonComponent::class)
 class ApplicationModule {
+    private val Context.dataStore: DataStore<Preferences> by preferencesDataStore(
+        name = Constants.DataStore.DEFAULT_DATASTORE_NAME
+    )
 
     @Provides
     fun resources(
@@ -33,8 +39,5 @@ class ApplicationModule {
     }
 
     @Provides
-    fun sharedPrefs(
-        @ApplicationContext context: Context,
-    ) =
-        PreferenceManager.getDefaultSharedPreferences(context)
+    fun dataStore(@ApplicationContext context: Context): DataStore<Preferences> = context.dataStore
 }

app/src/main/kotlin/app/futured/androidprojecttemplate/tools/Constants.kt

@@ -6,4 +6,8 @@ interface Constants {
         const val BASE_PROD_URL = "https://reqres.in/"
         const val TIMEOUT_IN_SECONDS = 30L
     }
+
+    object DataStore {
+        const val DEFAULT_DATASTORE_NAME = "preferences"
+    }
 }

buildSrc/src/main/kotlin/Dependencies.kt

@@ -37,9 +37,10 @@ object Dependencies {
         const val lifecycleCompiler = "androidx.lifecycle:lifecycle-compiler:${Versions.lifecycle}"
         const val desugarLibs = "com.android.tools:desugar_jdk_libs:${Versions.desugarLibs}"
 
+        const val datastore = "androidx.datastore:datastore-preferences:${Versions.datastore}"
+
         // Questionable
         const val vectordrawable = "androidx.vectordrawable:vectordrawable:${Versions.vectorDrawable}"
-        const val preference = "androidx.preference:preference-ktx:${Versions.preference}"
     }
 
     object NavigationComponents {

buildSrc/src/main/kotlin/Versions.kt

@@ -27,7 +27,7 @@ object Versions {
     const val lifecycle = "2.7.0"
     const val constraintLayout = "1.0.1"
     const val vectorDrawable = "1.2.0-beta01"
-    const val preference = "1.2.1"
+    const val datastore = "1.1.2"
 
     const val activity = "1.9.0"
     const val desugarLibs = "2.0.4"