Rezept für dynamische Feature-Module

object ExampleModule : DynamicModule(
    entryBuilderClassName = "com.example.module.ExampleEntryBuilder",
    moduleName = "example"
) {
    @Serializable
    data object Screen : AppNavKey
}

// Inside :example module

@Suppress("unused")
class ExampleEntryBuilder : DynamicModuleEntryBuilder {
    override fun EntryProviderScope<NavKey>.build() {
        appEntry<ExampleModule.Screen> {
            ExampleScreen()
        }
    }
}

@Composable
private fun ExampleScreen() {
    // ...
}

// Inside :app module

val ALL_DYNAMIC_MODULES_MAP = listOf(
   ExampleModule,
   // ...
).associateBy { it.moduleName }

NavDisplay(
    // ...
    entryProvider = entryProvider {
        // ...
        dynamicFeatureManager.installedModules
            .mapNotNull { ALL_DYNAMIC_MODULES_MAP[it] }
            .forEach { buildDynamicEntries(it) }
    }
)

// Inside :app module

// Initialize the manager
val dynamicFeatureManager = retainDynamicFeatureManager()

// E.g. in a Button's onClick
dynamicFeatureManager.installModule(
    moduleName = ExampleModule.moduleName,
    onModuleInstalled = {
        backStack.add(ExampleModule.Screen)
    }
)

DynamicFeatureDownloadProgressDialog(dynamicFeatureManager)

-keep class * implements com.example.nav3recipes.dynamicfeature.DynamicModuleEntryBuilder {
   public <init>();
}

/*
 * Copyright 2026 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.dynamicfeature

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.Button
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.lifecycle.compose.dropUnlessResumed
import androidx.navigation3.runtime.entryProvider
import androidx.navigation3.runtime.rememberNavBackStack
import androidx.navigation3.ui.NavDisplay
import com.example.nav3recipes.content.ContentGreen
import com.example.nav3recipes.ui.setEdgeToEdgeConfig
import kotlinx.serialization.Serializable

class DynamicFeatureActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        setEdgeToEdgeConfig()
        super.onCreate(savedInstanceState)
        setContent {
            val backStack = rememberNavBackStack(Home)
            val dynamicFeatureManager = retainDynamicFeatureManager()

            DynamicFeatureDownloadProgressDialog(dynamicFeatureManager)

            NavDisplay(
                backStack = backStack,
                onBack = { backStack.removeLastOrNull() },
                modifier = Modifier.fillMaxSize(),
                entryProvider = entryProvider {
                    appEntry<Home> {
                        HomeScreen(
                            onNavigateToInstallTime = {
                                dynamicFeatureManager.installModule(
                                    moduleName = InstallTimeModule.moduleName,
                                    onModuleInstalled = {
                                        backStack.add(InstallTimeModule.Home)
                                    }
                                )
                            },
                            onNavigateToOnDemand = {
                                dynamicFeatureManager.installModule(
                                    moduleName = OnDemandModule.moduleName,
                                    onModuleInstalled = {
                                        backStack.add(OnDemandModule.Home)
                                    }
                                )
                            },
                        )
                    }

                    dynamicFeatureManager.installedModules
                        .mapNotNull { ALL_DYNAMIC_MODULES_MAP[it] }
                        .forEach { buildDynamicEntries(it) }
                }
            )
        }
    }
}

@Composable
fun HomeScreen(
    onNavigateToInstallTime: () -> Unit,
    onNavigateToOnDemand: () -> Unit,
    modifier: Modifier = Modifier,
) {
    ContentGreen(
        title = "Home screen",
        modifier = modifier,
    ) {
        Column {
            Button(onClick = dropUnlessResumed { onNavigateToInstallTime() }) {
                Text(text = "Go to Install Time Module Screen")
            }
            Button(onClick = dropUnlessResumed { onNavigateToOnDemand() }) {
                Text(text = "Go to On Demand Module Screen")
            }
        }
    }
}

@Serializable
private data object Home : AppNavKey

private val ALL_DYNAMIC_MODULES_MAP = listOf(
    InstallTimeModule,
    OnDemandModule
).associateBy { it.moduleName }

object InstallTimeModule : DynamicModule(
    entryBuilderClassName = "com.example.dynamicfeature.installtime.InstallTimeEntryBuilder",
    moduleName = "installtime",
) {
    @Serializable
    data object Home : AppNavKey {
        override fun toContentKey(): Any {
            return "InstallTimeHome"
        }
    }
}

object OnDemandModule : DynamicModule(
    entryBuilderClassName = "com.example.dynamicfeature.ondemand.OnDemandEntryBuilder",
    moduleName = "ondemand"
) {
    @Serializable
    data object Home : AppNavKey {
        override fun toContentKey(): Any {
            return "OnDemandHome"
        }
    }
}
DynamicFeatureActivity.kt

/*
 * Copyright 2026 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.dynamicfeature

import android.content.Context
import androidx.activity.result.ActivityResultLauncher
import androidx.activity.result.IntentSenderRequest
import androidx.compose.runtime.Composable
import androidx.compose.runtime.DisposableEffect
import androidx.compose.runtime.Stable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.retain.retain
import androidx.compose.runtime.setValue
import androidx.compose.ui.platform.LocalContext
import com.google.android.play.core.ktx.bytesDownloaded
import com.google.android.play.core.ktx.errorCode
import com.google.android.play.core.ktx.sessionId
import com.google.android.play.core.ktx.status
import com.google.android.play.core.ktx.totalBytesToDownload
import com.google.android.play.core.splitinstall.SplitInstallManagerFactory
import com.google.android.play.core.splitinstall.SplitInstallRequest
import com.google.android.play.core.splitinstall.SplitInstallSessionState
import com.google.android.play.core.splitinstall.SplitInstallStateUpdatedListener
import com.google.android.play.core.splitinstall.model.SplitInstallSessionStatus

@Composable
fun retainDynamicFeatureManager(): DynamicFeatureManager {
    val applicationContext = LocalContext.current.applicationContext

    val manager = retain {
        DynamicFeatureManager(applicationContext)
    }

    DisposableEffect(manager) {
        onDispose {
            manager.dispose()
        }
    }

    return manager
}

sealed interface InstallStatus {
    data object Idle : InstallStatus
    data class Pending(val sessionId: Int) : InstallStatus
    data class Downloading(val sessionId: Int, val progress: Float) : InstallStatus
    data class Installing(val sessionId: Int) : InstallStatus
    data class RequiresUserConfirmation(val state: SplitInstallSessionState) : InstallStatus
    data class Failed(val sessionId: Int, val errorCode: Int) : InstallStatus
}

@Stable
class DynamicFeatureManager(context: Context) {
    private val splitInstallManager = SplitInstallManagerFactory.create(context)

    // Maintain a single listener for the lifetime of the manager
    private val listener = SplitInstallStateUpdatedListener { state ->
        val sessionId = state.sessionId
        // Capture session ID if we're expecting an install but haven't got the ID yet (race condition)
        if (activeSessionId == null && activeModuleName != null) {
            if (state.moduleNames().contains(activeModuleName)) {
                activeSessionId = sessionId
            }
        }

        if (sessionId == activeSessionId) {
            updateStatus(state)
        }
    }

    private var activeSessionId: Int? = null
    private var activeModuleName: String? = null
    private var onModuleInstalledCallback: (() -> Unit)? = null

    var status by mutableStateOf<InstallStatus>(InstallStatus.Idle)
        private set

    var installedModules: Set<String> by mutableStateOf(splitInstallManager.installedModules.toSet())
        private set

    init {
        splitInstallManager.registerListener(listener)
    }

    fun dispose() {
        splitInstallManager.unregisterListener(listener)
    }

    fun installModule(moduleName: String, onModuleInstalled: () -> Unit) {
        if (splitInstallManager.installedModules.contains(moduleName)) {
            onModuleInstalled()
            return
        }

        // Avoid starting multiple installs if one is already in progress
        if (status !is InstallStatus.Idle && status !is InstallStatus.Failed) return

        activeModuleName = moduleName
        onModuleInstalledCallback = onModuleInstalled
        // Use a placeholder ID to indicate we are waiting for a session
        status = InstallStatus.Pending(-1)

        splitInstallManager.startInstall(
            SplitInstallRequest.newBuilder().addModule(moduleName).build()
        ).addOnSuccessListener { sessionId ->
            if (activeSessionId == null) {
                activeSessionId = sessionId
            }
            // Only update status if it hasn't progressed beyond our placeholder
            if (status is InstallStatus.Pending && (status as InstallStatus.Pending).sessionId == -1) {
                status = InstallStatus.Pending(sessionId)
            }
        }.addOnFailureListener {
            status = InstallStatus.Failed(-1, -1)
            onModuleInstalledCallback = null
        }
    }

    private fun clearSessionState() {
        activeSessionId = null
        activeModuleName = null
        onModuleInstalledCallback = null
    }

    private fun updateStatus(state: SplitInstallSessionState) {
        val sessionId = state.sessionId
        when (state.status) {
            SplitInstallSessionStatus.PENDING -> {
                status = InstallStatus.Pending(sessionId)
            }

            SplitInstallSessionStatus.DOWNLOADING -> {
                val progress = if (state.totalBytesToDownload > 0) {
                    state.bytesDownloaded.toFloat() / state.totalBytesToDownload
                } else 0f
                status = InstallStatus.Downloading(sessionId, progress)
            }

            SplitInstallSessionStatus.DOWNLOADED -> {
                status = InstallStatus.Installing(sessionId)
            }

            SplitInstallSessionStatus.INSTALLING -> {
                status = InstallStatus.Installing(sessionId)
            }

            SplitInstallSessionStatus.REQUIRES_USER_CONFIRMATION -> {
                status = InstallStatus.RequiresUserConfirmation(state)
            }

            SplitInstallSessionStatus.INSTALLED -> {
                status = InstallStatus.Idle
                installedModules = splitInstallManager.installedModules.toSet()
                onModuleInstalledCallback?.invoke()
                clearSessionState()
            }

            SplitInstallSessionStatus.FAILED -> {
                status = InstallStatus.Failed(sessionId, state.errorCode)
                clearSessionState()
            }

            SplitInstallSessionStatus.CANCELING -> {
                status = InstallStatus.Pending(sessionId)
            }

            SplitInstallSessionStatus.CANCELED -> {
                status = InstallStatus.Idle
                clearSessionState()
            }

            SplitInstallSessionStatus.UNKNOWN -> {
                status = InstallStatus.Failed(sessionId, -1)
                clearSessionState()
            }
        }
    }

    fun startConfirmationDialogForResult(
        state: SplitInstallSessionState,
        launcher: ActivityResultLauncher<IntentSenderRequest>
    ) {
        splitInstallManager.startConfirmationDialogForResult(state, launcher)
    }

    fun cancelInstallModule() {
        activeSessionId?.let { id ->
            splitInstallManager.cancelInstall(id)
        }
        status = InstallStatus.Idle
        clearSessionState()
    }
}
DynamicFeatureManager.kt

/*
 * Copyright 2026 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.dynamicfeature

import androidx.navigation3.runtime.EntryProviderScope
import androidx.navigation3.runtime.NavKey

interface AppNavKey : NavKey {
    // By default, `toString()` is used to generate the `contentKey` for NavEntries.
    // Instead of overriding `toString()`, we provide a dedicated `toContentKey()` function to make
    // it possible to uniquely identify keys for nested objects with the same simple name
    // (e.g., `ModuleA.Home` vs `ModuleB.Home`), without polluting the `toString()` representation.
    fun toContentKey(): Any = this.toString()
}

/**
 * An extension on [EntryProviderScope] specifically for [AppNavKey]s that overrides the default
 * `contentKey` resolution. It explicitly resolves the key via `it.toContentKey()` instead of the default
 * string representation.
 */
inline fun <reified K : AppNavKey> EntryProviderScope<NavKey>.appEntry(
    noinline clazzContentKey: (key: @JvmSuppressWildcards K) -> Any = { it.toContentKey() },
    metadata: Map<String, Any> = emptyMap(),
    noinline content: @androidx.compose.runtime.Composable (K) -> Unit,
) {
    addEntryProvider(K::class, clazzContentKey, { metadata }, content)
}
AppNavKey.kt

/*
 * Copyright 2026 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.dynamicfeature


import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Button
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.dp
import kotlin.math.roundToInt

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun DynamicFeatureDownloadProgressDialog(
    dynamicFeatureManager: DynamicFeatureManager,
    modifier: Modifier = Modifier,
) {
    val status = dynamicFeatureManager.status

    if (status is InstallStatus.Idle) return

    val launcher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.StartIntentSenderForResult()
    ) {
        // The session status will be updated automatically via the
        // SplitInstallStateUpdatedListener in DynamicFeatureManager,
        // so no explicit handling is required here.
    }

    val progress = if (status is InstallStatus.Downloading) status.progress else 0f
    val progressPercentage = "${(progress * 100).roundToInt()}%"

    AlertDialog(
        onDismissRequest = {},
        modifier = modifier,
        title = {
            Text(text = getStatusTitle(status))
        },
        text = {
            Column(
                verticalArrangement = Arrangement.spacedBy(16.dp),
                horizontalAlignment = Alignment.CenterHorizontally,
                modifier = Modifier.fillMaxWidth(),
            ) {
                if (status is InstallStatus.Downloading) {
                    CircularProgressIndicator(
                        progress = { progress },
                        modifier = Modifier.semantics {
                            contentDescription = "Downloading: $progressPercentage"
                        }
                    )
                    Text(
                        text = progressPercentage,
                        style = MaterialTheme.typography.labelSmall,
                    )
                } else if (status !is InstallStatus.Failed && status !is InstallStatus.RequiresUserConfirmation) {
                    CircularProgressIndicator()
                }

                if (status is InstallStatus.Failed) {
                    Text(
                        text = "Error code: ${status.errorCode}",
                        color = MaterialTheme.colorScheme.error,
                        style = MaterialTheme.typography.bodySmall,
                    )
                }
            }
        },
        confirmButton = {
            if (status is InstallStatus.RequiresUserConfirmation) {
                Button(onClick = {
                    dynamicFeatureManager.startConfirmationDialogForResult(
                        status.state,
                        launcher
                    )
                }) {
                    Text(text = "Confirm Download")
                }
            }
        },
        dismissButton = {
            TextButton(onClick = dynamicFeatureManager::cancelInstallModule) {
                Text(text = "Cancel")
            }
        }
    )
}

private fun getStatusTitle(status: InstallStatus): String {
    return when (status) {
        is InstallStatus.Pending -> "Requesting..."
        is InstallStatus.Downloading -> "Downloading..."
        is InstallStatus.Installing -> "Installing..."
        is InstallStatus.RequiresUserConfirmation -> "Requires Confirmation"
        is InstallStatus.Failed -> "Installation Failed"
        else -> ""
    }
}
DynamicFeatureDownloadProgressDialog.kt

/*
 * Copyright 2026 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.dynamicfeature

import androidx.navigation3.runtime.EntryProviderScope
import androidx.navigation3.runtime.NavKey

/**
 * Base class for defining a dynamic feature module.
 *
 * Caches the [DynamicModuleEntryBuilder] instance to guarantee that the reflection instantiation
 * via [Class.forName] and [Class.newInstance] occurs exactly once per application process lifetime,
 * optimizing performance during recompositions when the `entryProvider` block is re-evaluated.
 */
abstract class DynamicModule(
    val entryBuilderClassName: String,
    val moduleName: String,
) {
    private var dynamicModuleEntryBuilder: DynamicModuleEntryBuilder? = null

    internal fun getDynamicModuleEntryBuilder(): DynamicModuleEntryBuilder {
        return dynamicModuleEntryBuilder ?: (Class.forName(entryBuilderClassName)
            .getConstructor()
            .newInstance() as DynamicModuleEntryBuilder).also { dynamicModuleEntryBuilder = it }
    }
}

/**
 * Interface that every dynamic feature module must implement to register its navigation entries.
 *
 * It is invoked by [buildDynamicEntries] to add the module's routes into the base [EntryProviderScope].
 *
 * **Example:**
 * ```kotlin
 * class ExampleEntryBuilder : DynamicModuleEntryBuilder {
 *     override fun EntryProviderScope<NavKey>.build() {
 *         appEntry<ExampleModule.Screen> {
 *             ExampleScreen()
 *         }
 *     }
 * }
 * ```
 */
fun interface DynamicModuleEntryBuilder {
    fun EntryProviderScope<NavKey>.build()
}

fun EntryProviderScope<NavKey>.buildDynamicEntries(
    module: DynamicModule,
) {
    with(module.getDynamicModuleEntryBuilder()) {
        build()
    }
}
DynamicModule.kt