Alex Vanyo
2 years ago
committed by
Don Turner
parent
707c9d04e7
commit
f9d8d45ecb
@ -1,91 +0,0 @@
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/*
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* Copyright 2022 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.samples.apps.nowinandroid.feature.foryou.util
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import androidx.compose.runtime.MutableState
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import androidx.compose.runtime.getValue
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import androidx.compose.runtime.saveable.Saver
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import androidx.compose.runtime.saveable.autoSaver
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import androidx.compose.runtime.setValue
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import androidx.lifecycle.SavedStateHandle
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import androidx.lifecycle.viewmodel.compose.SavedStateHandleSaveableApi
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import androidx.lifecycle.viewmodel.compose.saveable
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import kotlin.properties.PropertyDelegateProvider
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import kotlin.properties.ReadOnlyProperty
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import kotlin.properties.ReadWriteProperty
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import kotlin.reflect.KProperty
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// These are placeholder solutions for https://issuetracker.google.com/issues/224565154 and
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// https://issuetracker.google.com/issues/225014345.
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// With the following, it is possible to use the Compose Saver APIs to back values in the
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// SavedStateHandle to persist through process death, in a similar form as rememberSaveable
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/**
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* A [PropertyDelegateProvider] allowing the use of [saveable] with the key provided by the name
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* of the property.
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*
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* https://issuetracker.google.com/issues/225014345
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*/
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@OptIn(SavedStateHandleSaveableApi::class)
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fun <T : Any> SavedStateHandle.saveable(
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saver: Saver<T, out Any> = autoSaver(),
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init: () -> T,
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): PropertyDelegateProvider<Any, ReadOnlyProperty<Any, T>> =
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PropertyDelegateProvider { _, property ->
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val value = saveable(
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key = property.name,
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saver = saver,
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init = init
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)
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ReadOnlyProperty { _, _ -> value }
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}
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/**
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* A nested [PropertyDelegateProvider] allowing the use of [saveable] with the key provided by the
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* name, as well as direct access to the value contained with [MutableState].
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*
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* This allows the main usage to look almost identical to
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* `rememberSaveable { mutableStateOf(...) }`:
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*
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* ```
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* val value by savedStateHandle.saveable { mutableStateOf("initialValue") }
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* ```
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*
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* https://issuetracker.google.com/issues/225014345
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*/
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@OptIn(SavedStateHandleSaveableApi::class)
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@JvmName("saveableMutableState")
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fun <T : Any> SavedStateHandle.saveable(
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stateSaver: Saver<T, out Any> = autoSaver(),
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init: () -> MutableState<T>,
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): PropertyDelegateProvider<Any, ReadWriteProperty<Any, T>> =
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PropertyDelegateProvider<Any, ReadWriteProperty<Any, T>> { _, property ->
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val mutableState = saveable(
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key = property.name,
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stateSaver = stateSaver,
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init = init
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)
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object : ReadWriteProperty<Any, T> {
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override fun getValue(thisRef: Any, property: KProperty<*>): T =
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mutableState.getValue(thisRef, property)
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override fun setValue(thisRef: Any, property: KProperty<*>, value: T) =
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mutableState.setValue(thisRef, property, value)
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}
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}
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