Add NiaBackStack and BackStack providers

Bump agp versions and add navigation 3 dependency

app/build.gradle.kts

@@ -79,6 +79,7 @@ dependencies {
     implementation(projects.core.designsystem)
     implementation(projects.core.data)
     implementation(projects.core.model)
+    implementation(projects.core.navigation)
     implementation(projects.core.analytics)
     implementation(projects.sync.work)
 

app/src/main/kotlin/com/google/samples/apps/nowinandroid/di/BackStackProvider.kt

@@ -0,0 +1,34 @@
+/*
+ * 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
+ *
+ *     https://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.di
+
+import com.google.samples.apps.nowinandroid.core.navigation.NiaBackStack
+import com.google.samples.apps.nowinandroid.navigation.TopLevelDestination
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import javax.inject.Singleton
+import dagger.hilt.components.SingletonComponent
+
+@Module
+@InstallIn(SingletonComponent::class)
+object NiaAppNavigation {
+    @Provides
+    @Singleton
+    fun provideNiaBackStack(): NiaBackStack =
+        NiaBackStack(startKey = TopLevelDestination.FOR_YOU)
+}

build-logic/convention/src/main/kotlin/AndroidApplicationConventionPlugin.kt

@@ -37,7 +37,7 @@ class AndroidApplicationConventionPlugin : Plugin<Project> {
 
             extensions.configure<ApplicationExtension> {
                 configureKotlinAndroid(this)
-                defaultConfig.targetSdk = 35
+                defaultConfig.targetSdk = 36
                 @Suppress("UnstableApiUsage")
                 testOptions.animationsDisabled = true
                 configureGradleManagedDevices(this)

build-logic/convention/src/main/kotlin/AndroidLibraryConventionPlugin.kt

@@ -37,7 +37,7 @@ class AndroidLibraryConventionPlugin : Plugin<Project> {
 
             extensions.configure<LibraryExtension> {
                 configureKotlinAndroid(this)
-                defaultConfig.targetSdk = 35
+                defaultConfig.targetSdk = 36
                 defaultConfig.testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
                 testOptions.animationsDisabled = true
                 configureFlavors(this)

build-logic/convention/src/main/kotlin/AndroidTestConventionPlugin.kt

@@ -30,7 +30,7 @@ class AndroidTestConventionPlugin : Plugin<Project> {
 
             extensions.configure<TestExtension> {
                 configureKotlinAndroid(this)
-                defaultConfig.targetSdk = 35
+                defaultConfig.targetSdk = 36
                 configureGradleManagedDevices(this)
             }
         }

build-logic/convention/src/main/kotlin/com/google/samples/apps/nowinandroid/KotlinAndroid.kt

@@ -35,7 +35,7 @@ internal fun Project.configureKotlinAndroid(
     commonExtension: CommonExtension<*, *, *, *, *, *>,
 ) {
     commonExtension.apply {
-        compileSdk = 35
+        compileSdk = 36
 
         defaultConfig {
             minSdk = 21

core/navigation/.gitignore

@@ -0,0 +1 @@
+/build

core/navigation/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    alias(libs.plugins.nowinandroid.jvm.library)
+    alias(libs.plugins.nowinandroid.hilt)
+}
+
+dependencies {
+    implementation(libs.androidx.navigation3.runtime)
+}

core/navigation/src/main/kotlin/com/google/samples/apps/nowinandroid/core/navigation/NiaBackStack.kt

@@ -0,0 +1,77 @@
+/*
+ * 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
+ *
+ *     https://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
+
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateListOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshots.SnapshotStateList
+import javax.inject.Inject
+import kotlin.collections.remove
+
+class NiaBackStack @Inject constructor(
+    startKey: Any,
+) {
+    val backStack = mutableStateListOf(startKey)
+
+    // Maintain a stack for each top level route
+    private var topLevelStacks : LinkedHashMap<Any, SnapshotStateList<Any>> = linkedMapOf(
+        startKey to mutableStateListOf(startKey)
+    )
+
+    // Expose the current top level route for consumers
+    var topLevelKey by mutableStateOf(startKey)
+        private set
+
+    private fun updateBackStack() =
+        backStack.apply {
+            clear()
+            addAll(topLevelStacks.flatMap { it.value })
+        }
+
+    fun navigateToTopLevelDestination(key: Any){
+        // If the top level doesn't exist, add it
+        if (topLevelStacks[key] == null){
+            topLevelStacks.put(key, mutableStateListOf(key))
+        } else {
+            // Otherwise just move it to the end of the stacks
+            topLevelStacks.apply {
+                remove(key)?.let {
+                    put(key, it)
+                }
+            }
+        }
+        topLevelKey = key
+        updateBackStack()
+    }
+
+    fun navigate(key: Any){
+        println("cfok navigate $key")
+        topLevelStacks[topLevelKey]?.add(key)
+        updateBackStack()
+    }
+
+    fun removeLast(){
+        val removedKey = topLevelStacks[topLevelKey]?.removeLastOrNull()
+        // If the removed key was a top level key, remove the associated top level stack
+        topLevelStacks.remove(removedKey)
+        topLevelKey = topLevelStacks.keys.last()
+        updateBackStack()
+    }
+
+}

gradle/libs.versions.toml

@@ -2,8 +2,8 @@
 accompanist = "0.37.0"
 androidDesugarJdkLibs = "2.1.4"
 # AGP and tools should be updated together
-androidGradlePlugin = "8.9.0"
+androidGradlePlugin = "8.9.3"
-androidTools = "31.9.0"
+androidTools = "31.9.3"
 androidxActivity = "1.9.3"
 androidxAppCompat = "1.7.0"
 androidxBrowser = "1.8.0"
@@ -21,6 +21,7 @@ androidxLintGradle = "1.0.0-alpha03"
 androidxMacroBenchmark = "1.3.4"
 androidxMetrics = "1.0.0-beta01"
 androidxNavigation = "2.8.5"
+androidxNavigation3 = "1.0.0-alpha03"
 androidxProfileinstaller = "1.4.1"
 androidxTestCore = "1.7.0-rc01"
 androidxTestExt = "1.3.0-rc01"
@@ -99,6 +100,8 @@ androidx-lint-gradle = { group = "androidx.lint", name = "lint-gradle", version.
 androidx-metrics = { group = "androidx.metrics", name = "metrics-performance", version.ref = "androidxMetrics" }
 androidx-navigation-compose = { group = "androidx.navigation", name = "navigation-compose", version.ref = "androidxNavigation" }
 androidx-navigation-testing = { group = "androidx.navigation", name = "navigation-testing", version.ref = "androidxNavigation" }
+androidx-navigation3-runtime = { group = "androidx.navigation3", name = "navigation3-runtime", version.ref = "androidxNavigation3" }
+androidx-navigation3-ui = { group = "androidx.navigation3", name = "navigation3-ui", version.ref = "androidxNavigation3" }
 androidx-profileinstaller = { group = "androidx.profileinstaller", name = "profileinstaller", version.ref = "androidxProfileinstaller" }
 androidx-test-core = { group = "androidx.test", name = "core", version.ref = "androidxTestCore" }
 androidx-test-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "androidxEspresso" }

settings.gradle.kts

@@ -59,6 +59,7 @@ include(":core:datastore-test")
 include(":core:designsystem")
 include(":core:domain")
 include(":core:model")
+include(":core:navigation")
 include(":core:network")
 include(":core:notifications")
 include(":core:screenshot-testing")