SavedStateHandleSaver.kt
/*
* Copyright 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.lifecycle.viewmodel.compose
import android.os.Bundle
import androidx.compose.runtime.saveable.autoSaver
import androidx.compose.runtime.saveable.Saver
import androidx.compose.runtime.saveable.SaverScope
import androidx.core.os.bundleOf
import androidx.lifecycle.SavedStateHandle
import androidx.lifecycle.SavedStateHandle.Companion.validateValue
/**
* Inter-opt between [SavedStateHandle] and [rememberSaveable] so that any state holder that is
* being saved via [rememberSaveable] can also be saved with [SavedStateHandle].
*/
@SavedStateHandleSaveableApi
fun <T : Any> SavedStateHandle.saveable(
key: String,
saver: Saver<T, out Any> = autoSaver(),
init: () -> T,
): T {
@Suppress("UNCHECKED_CAST")
saver as Saver<T, Any>
// value is restored using the SavedStateHandle or created via [init] lambda
@Suppress("DEPRECATION") // Bundle.get has been deprecated in API 31
val value = get<Bundle?>(key)?.get("value")?.let(saver::restore) ?: init()
// Hook up saving the state to the SavedStateHandle
setSavedStateProvider(key) {
bundleOf("value" to with(saver) {
SaverScope { validateValue(value) }.save(value)
})
}
return value
}