Preference via delegates + JetPack DataStore Storage + DSL for RecyclerView

MaterialPreferences

This library is based on Flows and Coroutines and works with the provided DataStore Storage or even with a custom storage implementation.
It supports LiveData by default as Flows can easily be converted to LiveData. Preferences are elegantly declared via delegates.
Additionally the preference-screen module provides a DSL to easily set up RecyclerView based preference screens.
It also supports custom extensions for custom preference screens.

Following are the key features:

• define preferences elegantly via delegates
• flow and coroutine based
• allows to observe single / some / all preferences
• provides suspending update functions
• provides a DSL for a RecyclerView based setting screen

Core

With this library you can declare preferences via kotlin delegates,and observe and update them via kotlin Flows. This works with any storage implementation, an implementation for JetPack DataStore is provided already.

1/4 Define preferences:

object UserSettingsModel : SettingsModel(DataStoreStorage(name = "user")) {

  // Basic
  val name by stringPref("User")
  val alive by boolPref(true)
  val hairColor by intPref(Color.parseColor("#A52A2A"))
  val age by intPref(40)
  val income by floatPref(50000f)
  val dayOfBirth by longPref(0L)
  
  // Sets
  val childrenAges by intSetPref(setOf(20, 18, 16))
  val childrenIncomes by floatSetPref(setOf(30000f, 10000f, 0f))
  val childrenDaysOfBirth by longSetPref(setOf(0L, 0L, 0L))
  
  // Enum
  val car by enumPref(Car.Tesla)
  
  // custom class - provide a custom converter (String <=> Class)
  val testClass by anyPref(TestClass.CONVERTER, TestClass())
}

2/4 Observe/Read preferences:

// 1) simply observe a setting
UserSettingsModel.name.observe(lifecycleScope) {
	L.d { "name = $it"}
}

// 2) direct read (not recommended if not necessary but may be useful in many cases => simply returns flow.first() in a blocking way)
val name = UserSettingsModel.name.value

// 3) observe a setting once
UserSettingsModel.name.observeOnce(lifecycleScope) {
	L.d { "name = $it"}
}

// 4) observe ALL settings
UserSettingsModel.changes.onEach {
	L.d { "[ALL SETTINGS OBSERVER] Setting '${it.setting.key}' changed its value to ${it.value}" }
}.launchIn(lifecycleScope)

// 5) observe SOME settings
UserSettingsModel.changes´
	.filter {
		it.setting == UserSettingsModel.name ||
		it.setting == UserSettingsModel.age
	}.onEach {
		// we know that either the name or the age changes
		L.d { "[SOME SETTINGS OBSERVER] Setting '${it.setting.key}' changed its value to ${it.value}" }
	}.launchIn(lifecycleScope)
	
// 6) read multiple settings in a suspending way
lifecycleScope.launch(Dispatchers.IO) {
  val name = UserSettingsModel.childName1.flow.first()
  val alive = DemoSettingsModel.alive.flow.first()
  val hairColor = DemoSettingsModel.hairColor.flow.first()
  withContext(Dispatchers.Main) {
	textView.text = "Informations: $name, $alive, $hairColor"
  }
}

3/4 Lifedata:

val lifedata = UserSettingsModel.name.flow.asLiveData()

4/4 Update preferences:

lifecycleScope.launch(Dispatchers.IO)  {
  UserSettingsModel.name.update("Some new name")
  UserSettingsModel.age.update(30)
}

Storage

The Storage is an abstraction to support any storage implementation. The datastore module provides an implementation based on the Android JetPack DataStore.

Preference Screen

The preference-screen* modules allow you to create preference screens like following easily via DSL.

Gradle (via JitPack.io)

1. add jitpack to your project's build.gradle:

repositories {
    maven { url "https://jitpack.io" }
}

2. add the compile statement to your module's build.gradle:

dependencies {

  // core module
  implementation "com.github.MFlisar.MaterialPreferences:core:<LATEST-VERSION>"

  // data store module
  implementation "com.github.MFlisar.MaterialPreferences:datastore:<LATEST-VERSION>"
    
  // screen modules
  implementation "com.github.MFlisar.MaterialPreferences:screen:<LATEST-VERSION>"
  implementation "com.github.MFlisar.MaterialPreferences:screen-input:<LATEST-VERSION>"
  implementation "com.github.MFlisar.MaterialPreferences:screen-choice:<LATEST-VERSION>"
  implementation "com.github.MFlisar.MaterialPreferences:screen-color:<LATEST-VERSION>"
}

GitHub

https://github.com/MFlisar/MaterialPreferences