androidx.savedstate.serialization

inline fun <T : Any> decodeFromSavedState(savedState: SavedState): T

Decode a serializable object from a SavedState with the default deserializer.

import androidx.savedstate.serialization.decodeFromSavedState

class UUIDSerializer : KSerializer<UUID> {
    override val descriptor: SerialDescriptor
        get() = PrimitiveSerialDescriptor("UUIDSerializer", PrimitiveKind.STRING)

    override fun deserialize(decoder: Decoder): UUID {
        return UUID.fromString(decoder.decodeString())
    }

    override fun serialize(encoder: Encoder, value: UUID) {
        encoder.encodeString(value.toString())
    }
}
val uuid = decodeFromSavedState(UUIDSerializer(), uuidSavedState)

fun <T : Any> decodeFromSavedState(
    deserializer: <Error class: unknown class><T>,
    savedState: SavedState
): T

Decode a serializable object from a SavedState with an explicit deserializer, which can be a custom or third-party one.

import androidx.savedstate.serialization.decodeFromSavedState

@Serializable data class User(val id: Int, val name: String)
val user = decodeFromSavedState<User>(userSavedState)

inline fun <T : Any> encodeToSavedState(serializable: T): SavedState

Encode a serializable object to a SavedState with the default serializer.

import androidx.savedstate.serialization.encodeToSavedState

class UUIDSerializer : KSerializer<UUID> {
    override val descriptor: SerialDescriptor
        get() = PrimitiveSerialDescriptor("UUIDSerializer", PrimitiveKind.STRING)

    override fun deserialize(decoder: Decoder): UUID {
        return UUID.fromString(decoder.decodeString())
    }

    override fun serialize(encoder: Encoder, value: UUID) {
        encoder.encodeString(value.toString())
    }
}
encodeToSavedState(UUIDSerializer(), UUID.randomUUID())

fun <T : Any> encodeToSavedState(
    serializer: <Error class: unknown class><T>,
    value: T
): SavedState

Encode a serializable object to a SavedState with an explicit serializer, which can be a custom or third-party one.

import androidx.savedstate.serialization.encodeToSavedState

@Serializable data class User(val id: Int, val name: String)
val user = User(123, "foo")
val savedState = encodeToSavedState(user)

inline fun <T : Any> SavedStateRegistryOwner.saved(noinline init: () -> T): ReadWriteProperty<Any?, T>

Returns a property delegate provider that manages the saving and restoring of a value of type T within the SavedStateRegistry of this SavedStateRegistryOwner.

This is a convenience overload that uses the serializer function to obtain the serializer for the reified type T.

The name of the property will be used as the key for storing the value in the SavedStateRegistry.

import androidx.activity.ComponentActivity

@Serializable data class User(val id: Int, val name: String)
class MyActivity : ComponentActivity() {
    val user by saved { User(id = 123, name = "John Doe") }
}

inline fun <T : Any> SavedStateRegistryOwner.saved(key: String, noinline init: () -> T): ReadWriteProperty<Any?, T>

Returns a property delegate provider that manages the saving and restoring of a value of type T within the SavedStateRegistry of this SavedStateRegistryOwner.

import androidx.activity.ComponentActivity

@Serializable data class User(val id: Int, val name: String)
class MyActivity : ComponentActivity() {
    val user by saved(key = "myKey") { User(id = 123, name = "John Doe") }
}

fun <T : Any> SavedStateRegistryOwner.saved(
    serializer: <Error class: unknown class><T>,
    init: () -> T
): ReadWriteProperty<Any?, T>

Returns a property delegate provider that manages the saving and restoring of a value of type T within the SavedStateRegistry of this SavedStateRegistryOwner.

This is a convenience overload that uses the name of the property as the key for storing the value in the SavedStateRegistry

import androidx.activity.ComponentActivity

@Serializable data class User(val id: Int, val name: String)
class MyActivity : ComponentActivity() {
    val user by saved(serializer = serializer()) { User(id = 123, name = "John Doe") }
}

fun <T : Any> SavedStateRegistryOwner.saved(
    key: String,
    serializer: <Error class: unknown class><T>,
    init: () -> T
): ReadWriteProperty<Any?, T>

Returns a property delegate provider that manages the saving and restoring of a value of type T within the SavedStateRegistry of this SavedStateRegistryOwner.

import androidx.activity.ComponentActivity

@Serializable data class User(val id: Int, val name: String)
class MyActivity : ComponentActivity() {
    val user by
        saved(key = "myKey", serializer = serializer()) { User(id = 123, name = "John Doe") }
}