Don Turner
9 months ago
parent
adcc3871be
commit
c9bba49957
@ -0,0 +1,108 @@
|
|||||||
|
/*
|
||||||
|
* Copyright 2025 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 com.google.samples.apps.nowinandroid.core.navigation.simple
|
||||||
|
|
||||||
|
import androidx.compose.runtime.Composable
|
||||||
|
import androidx.compose.runtime.MutableState
|
||||||
|
import androidx.compose.runtime.getValue
|
||||||
|
import androidx.compose.runtime.mutableStateOf
|
||||||
|
import androidx.compose.runtime.remember
|
||||||
|
import androidx.compose.runtime.saveable.rememberSerializable
|
||||||
|
import androidx.compose.runtime.setValue
|
||||||
|
import androidx.compose.runtime.snapshots.SnapshotStateList
|
||||||
|
import androidx.compose.runtime.toMutableStateList
|
||||||
|
import androidx.navigation3.runtime.NavBackStack
|
||||||
|
import androidx.navigation3.runtime.NavEntry
|
||||||
|
import androidx.navigation3.runtime.NavKey
|
||||||
|
import androidx.navigation3.runtime.rememberDecoratedNavEntries
|
||||||
|
import androidx.navigation3.runtime.rememberNavBackStack
|
||||||
|
import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
|
||||||
|
import androidx.navigation3.runtime.serialization.NavKeySerializer
|
||||||
|
import androidx.savedstate.compose.serialization.serializers.MutableStateSerializer
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Create a navigation state that persists config changes and process death.
|
||||||
|
*/
|
||||||
|
@Composable
|
||||||
|
fun rememberNavigationState(
|
||||||
|
startRoute: NavKey,
|
||||||
|
topLevelRoutes: Set<NavKey>
|
||||||
|
): NavigationState {
|
||||||
|
|
||||||
|
val topLevelRoute = rememberSerializable(
|
||||||
|
startRoute, topLevelRoutes,
|
||||||
|
serializer = MutableStateSerializer(NavKeySerializer())
|
||||||
|
) {
|
||||||
|
mutableStateOf(startRoute)
|
||||||
|
}
|
||||||
|
|
||||||
|
val backStacks = topLevelRoutes.associateWith { key -> rememberNavBackStack(key) }
|
||||||
|
|
||||||
|
return remember(startRoute, topLevelRoutes) {
|
||||||
|
NavigationState(
|
||||||
|
startRoute = startRoute,
|
||||||
|
topLevelRoute = topLevelRoute,
|
||||||
|
backStacks = backStacks
|
||||||
|
)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* State holder for navigation state.
|
||||||
|
*
|
||||||
|
* @param startRoute - the start route. The user will exit the app through this route.
|
||||||
|
* @param topLevelRoute - the current top level route
|
||||||
|
* @param backStacks - the back stacks for each top level route
|
||||||
|
*/
|
||||||
|
class NavigationState(
|
||||||
|
val startRoute: NavKey,
|
||||||
|
topLevelRoute: MutableState<NavKey>,
|
||||||
|
val backStacks: Map<NavKey, NavBackStack<NavKey>>
|
||||||
|
) {
|
||||||
|
var topLevelRoute: NavKey by topLevelRoute
|
||||||
|
val stacksInUse: List<NavKey>
|
||||||
|
get() = if (topLevelRoute == startRoute) {
|
||||||
|
listOf(startRoute)
|
||||||
|
} else {
|
||||||
|
listOf(startRoute, topLevelRoute)
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Convert NavigationState into NavEntries.
|
||||||
|
*/
|
||||||
|
@Composable
|
||||||
|
fun NavigationState.toEntries(
|
||||||
|
entryProvider: (NavKey) -> NavEntry<NavKey>
|
||||||
|
): SnapshotStateList<NavEntry<NavKey>> {
|
||||||
|
|
||||||
|
val decoratedEntries = backStacks.mapValues { (_, stack) ->
|
||||||
|
val decorators = listOf(
|
||||||
|
rememberSaveableStateHolderNavEntryDecorator<NavKey>(),
|
||||||
|
)
|
||||||
|
rememberDecoratedNavEntries(
|
||||||
|
backStack = stack,
|
||||||
|
entryDecorators = decorators,
|
||||||
|
entryProvider = entryProvider
|
||||||
|
)
|
||||||
|
}
|
||||||
|
|
||||||
|
return stacksInUse
|
||||||
|
.flatMap { decoratedEntries[it] ?: emptyList() }
|
||||||
|
.toMutableStateList()
|
||||||
|
}
|
||||||
@ -0,0 +1,47 @@
|
|||||||
|
/*
|
||||||
|
* Copyright 2025 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 com.example.nav3recipes.multiplestacks
|
||||||
|
|
||||||
|
import androidx.navigation3.runtime.NavKey
|
||||||
|
import com.google.samples.apps.nowinandroid.core.navigation.simple.NavigationState
|
||||||
|
|
||||||
|
/**
|
||||||
|
* Handles navigation events (forward and back) by updating the navigation state.
|
||||||
|
*/
|
||||||
|
class Navigator(val state: NavigationState){
|
||||||
|
fun navigate(route: NavKey){
|
||||||
|
if (route in state.backStacks.keys){
|
||||||
|
// This is a top level route, just switch to it
|
||||||
|
state.topLevelRoute = route
|
||||||
|
} else {
|
||||||
|
state.backStacks[state.topLevelRoute]?.add(route)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
fun goBack(){
|
||||||
|
val currentStack = state.backStacks[state.topLevelRoute] ?:
|
||||||
|
error("Stack for ${state.topLevelRoute} not found")
|
||||||
|
val currentRoute = currentStack.last()
|
||||||
|
|
||||||
|
// If we're at the base of the current route, go back to the start route stack.
|
||||||
|
if (currentRoute == state.topLevelRoute){
|
||||||
|
state.topLevelRoute = state.startRoute
|
||||||
|
} else {
|
||||||
|
currentStack.removeLastOrNull()
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
Loading…
Reference in new issue