FragmentState.kt
/*
* Copyright 2024 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.fragment.compose
import androidx.compose.runtime.Composable
import androidx.compose.runtime.MutableState
import androidx.compose.runtime.Stable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.saveable.Saver
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.fragment.app.Fragment
/**
* Creates a [FragmentState] used to store the state of a [Fragment] that is created via
* [AndroidFragment].
*/
@Composable
fun rememberFragmentState(): FragmentState {
return rememberSaveable(saver = fragmentStateSaver()) {
FragmentState()
}
}
/**
* Holder for the fragment state.
*/
@Stable
class FragmentState(
internal var state: MutableState<Fragment.SavedState?> = mutableStateOf(null)
)
/**
* Saver to save and restore the [FragmentState] across config change and process death.
*/
private fun fragmentStateSaver(): Saver<FragmentState, *> = Saver(
save = { it.state },
restore = { FragmentState(it) }
)