Filter Android JetPack Preferences DataStore

Question

Suppose that I have a datastore that contains some booleanPrefrencesKey

val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "settings")

I want to get all the keys that its value is true:

suspend fun getTrueKeys(): Set<Preferences.Key<*>>? {
     ...
}

How can I achieve that? Thanks

Answer 1

First we create a function to get all available keys and can modify the solution of @rasfarr5 to filter these key

suspend fun getAllKeys(): Set<Preferences.Key<*>>? = context.assetStatusDS.data
    .map {
        it.asMap().keys
    }.firstOrNull()

suspend fun getKeysWith(condition: Boolean): Set<Preferences.Key<*>>? {
    return getAllKeys()?.filter { key ->
        context.assetStatusDS.data.map {
            it[key] == condition
        }.firstOrNull()!!
    }?.toSet()
}

Answer 2

One possible approach that I can think of, keep all your keys in list like:

  val keys = listOf("key1", "key2")
  context.dataStore.data.map { preferences ->
      val keyWithTrueValue = keys.filter { key ->
        preferences[key]!! == true
      }

      // keyWithTrueValue now contains all true value keys
  }

Answer 3

I faced a similar issue. Here's what I ended up implementing:

suspend fun getTrueKeys() : Set<Preferences.Key<*>>? {
    var keys = context.dataStore.data.map {
            preferences ->
        preferences.asMap().filter {
            it.value == true
        }.keys
    }.first()

    return keys
}

Hope that it can help someone else facing this!

And in my specific case, it was to support a Datastore I can use across multiple widgets with a prefix