App architecture | Android Developers

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本食譜示範如何使用 Navigation 3 和 Koin 進行依附元件插入，建構多模組應用程式。目標是建立解耦架構，在不同的功能模組中定義及實作導覽功能。這項功能會使用 koin-compose-navigation3 構件。

運作方式

應用程式分為多個 Android 模組：

app 模組：這是主要應用程式模組。這個模組提供 KoinDeepLinkActivity (示範一般和深層連結意圖啟動的進入點)、KoinModularActivity (代管 NavDisplay 並將深層連結意圖委派給 Navigator.handleDeepLink(intent))，並初始化常見的 Navigator (透過 getAll() 解析所有已註冊的 BackStackMatcher<*, NavKey>)。
common 模組：這個模組包含應用程式模組和功能模組使用的核心導覽邏輯，包括：
- Navigator 類別，可管理返回堆疊、解析傳入的深層連結 Intent，並透過 handleDeepLink(intent) 建構合成返回堆疊。
- 用於初始化返回堆疊的 startDestination: NavKey。
- BackStackMatcher<*, NavKey>，功能模組會使用這個類別，透過合成返回堆疊提供深層連結比對器。
功能模組 (例如 conversation、profile)：每個功能都會拆分成兩個子模組：
- api 模組：定義功能的公開 API，包括導覽路徑和深層連結 URI 模式。這樣一來，其他模組就能前往這項功能，而不必瞭解實作細節。
- impl 模組：提供功能的實作，包括可組合項和 Koin Module。Koin 模組會使用 navigation DSL 定義項目供應器安裝程式，並透過 .withBackStack 設定 single<BackStackMatcher<*, NavKey>>(named<...>())，建立適當的階層式返回堆疊 (例如 [ConversationList, ConversationDetail(id)])。

這種模組化方法可明確區隔職責，讓程式碼集更具擴充性且易於維護。每個功能都負責自己的導覽邏輯，而 app 模組只會將這些片段組合在一起。

探索

前往 GitHub 查看完整食譜。

package com.example.nav3recipes.modular.koin

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.navigation3.runtime.NavKey
import androidx.navigation3.runtime.deeplink.BackStackMatcher
import androidx.navigation3.runtime.deeplink.DeepLinkUri
import androidx.navigation3.runtime.deeplink.UriDeepLinkMatcher
import androidx.navigation3.runtime.deeplink.withBackStack
import kotlinx.serialization.Serializable
import org.koin.androidx.scope.dsl.activityRetainedScope
import org.koin.core.annotation.KoinExperimentalAPI
import org.koin.core.qualifier.named
import org.koin.dsl.module
import org.koin.dsl.navigation3.navigation

// API
@Serializable
object Profile : NavKey

const val PROFILE_URI = "https://www.nav3recipes.com/profile"

// IMPL
@OptIn(KoinExperimentalAPI::class)
val profileModule = module {
    activityRetainedScope {
        navigation<Profile> { ProfileScreen() }
    }

    single<BackStackMatcher<*, NavKey>>(named<Profile>()) {
        UriDeepLinkMatcher(
            uriPattern = DeepLinkUri(PROFILE_URI),
            serializer = Profile.serializer(),
        ).withBackStack { matchResult ->
            listOf(ConversationList, matchResult.key)
        }
    }
}

@Composable
private fun ProfileScreen() {
    val profileColor = MaterialTheme.colorScheme.surfaceVariant
    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(profileColor)
            .padding(16.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Text(
            text = "Profile Screen",
            style = MaterialTheme.typography.headlineMedium,
            color = MaterialTheme.colorScheme.onSurface
        )
    }
}
ProfileModule.kt

package com.example.nav3recipes.modular.koin

import androidx.compose.foundation.background
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.material3.Button
import androidx.compose.material3.ListItem
import androidx.compose.material3.ListItemDefaults
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.unit.dp
import androidx.lifecycle.compose.dropUnlessResumed
import androidx.navigation3.runtime.NavKey
import androidx.navigation3.runtime.deeplink.BackStackMatcher
import androidx.navigation3.runtime.deeplink.DeepLinkUri
import androidx.navigation3.runtime.deeplink.UriDeepLinkMatcher
import androidx.navigation3.runtime.deeplink.withBackStack
import com.example.nav3recipes.ui.theme.colors
import kotlinx.serialization.Serializable
import org.koin.androidx.scope.dsl.activityRetainedScope
import org.koin.core.annotation.KoinExperimentalAPI
import org.koin.core.qualifier.named
import org.koin.dsl.module
import org.koin.dsl.navigation3.navigation

// API
object ConversationList : NavKey

@Serializable
data class ConversationDetail(val id: Int) : NavKey {
    val color: Color
        get() = colors[id % colors.size]
}

const val CONVERSATION_URI = "https://www.nav3recipes.com/conversation"

// IMPL
@OptIn(KoinExperimentalAPI::class)
val conversationModule = module {
    activityRetainedScope {
        navigation<ConversationList> {
            ConversationListScreen(
                onConversationClicked = { conversationDetail ->
                    get<Navigator>().goTo(conversationDetail)
                }
            )
        }

        navigation<ConversationDetail> { key ->
            ConversationDetailScreen(key) {
                get<Navigator>().goTo(Profile)
            }
        }
    }

    single<BackStackMatcher<*, NavKey>>(named<ConversationDetail>()) {
        UriDeepLinkMatcher(
            uriPattern = DeepLinkUri("$CONVERSATION_URI/{id}"),
            serializer = ConversationDetail.serializer(),
        ).withBackStack { matchResult ->
            listOf(ConversationList, matchResult.key)
        }
    }
}

@Composable
private fun ConversationListScreen(
    onConversationClicked: (ConversationDetail) -> Unit
) {
    LazyColumn(
        modifier = Modifier.fillMaxSize(),
    ) {
        items(10) { index ->
            val conversationId = index + 1
            val conversationDetail = ConversationDetail(conversationId)
            val backgroundColor = conversationDetail.color
            ListItem(
                modifier = Modifier
                    .fillMaxWidth()
                    .clickable(onClick = dropUnlessResumed {
                        onConversationClicked(conversationDetail)
                    }),
                headlineContent = {
                    Text(
                        text = "Conversation $conversationId",
                        style = MaterialTheme.typography.headlineSmall,
                        color = MaterialTheme.colorScheme.onSurface
                    )
                },
                colors = ListItemDefaults.colors(
                    containerColor = backgroundColor // Set container color directly
                )
            )
        }
    }
}

@Composable
private fun ConversationDetailScreen(
    conversationDetail: ConversationDetail,
    onProfileClicked: () -> Unit
) {
    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(conversationDetail.color)
            .padding(16.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Text(
            text = "Conversation Detail Screen: ${conversationDetail.id}",
            style = MaterialTheme.typography.headlineMedium,
            color = MaterialTheme.colorScheme.onSurface
        )
        Spacer(modifier = Modifier.height(16.dp))
        Button(onClick = dropUnlessResumed(block = onProfileClicked)) {
            Text("View Profile")
        }
    }
}
ConversationModule.kt

package com.example.nav3recipes.modular.koin

import android.content.Intent
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.snapshots.SnapshotStateList
import androidx.navigation3.runtime.NavKey
import androidx.navigation3.runtime.deeplink.BackStackMatcher
import androidx.navigation3.runtime.deeplink.DeepLinkRequest
import androidx.navigation3.runtime.deeplink.invoke

class Navigator(
    startDestination: NavKey,
    private val deepLinkMatchers: List<BackStackMatcher<*, NavKey>>,
) {
    val backStack: SnapshotStateList<NavKey> = mutableStateListOf(startDestination)

    fun goTo(destination: NavKey) {
        backStack.add(destination)
    }

    fun handleDeepLink(intent: Intent) {
        if (intent.data == null && intent.extras == null) return

        val request = DeepLinkRequest(intent)
        val matchResult = deepLinkMatchers.firstNotNullOfOrNull { matcher ->
            matcher.match(request)
        } ?: return

        backStack.clear()
        backStack.addAll(matchResult.backStack)
    }

    fun goBack() {
        backStack.removeLastOrNull()
    }
}CommonModule.kt

package com.example.nav3recipes.modular.koin

import org.koin.androidx.scope.dsl.activityRetainedScope
import org.koin.dsl.module

val appModule = module {
    includes(profileModule, conversationModule)

    activityRetainedScope {
        scoped {
            Navigator(
                startDestination = ConversationList,
                deepLinkMatchers = getAll(),
            )
        }
    }
}AppModule.kt

package com.example.nav3recipes.modular.koin

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.padding
import androidx.compose.material3.Scaffold
import androidx.compose.ui.Modifier
import androidx.navigation3.ui.NavDisplay
import com.example.nav3recipes.ui.setEdgeToEdgeConfig
import org.koin.android.ext.android.inject
import org.koin.android.scope.AndroidScopeComponent
import org.koin.androidx.compose.navigation3.getEntryProvider
import org.koin.androidx.scope.activityRetainedScope
import org.koin.core.Koin
import org.koin.core.annotation.KoinExperimentalAPI
import org.koin.core.component.KoinComponent
import org.koin.core.scope.Scope
import org.koin.dsl.koinApplication

/**
 * This recipe demonstrates how to use a modular approach with Navigation 3,
 * where different parts of the application are defined in separate modules and injected
 * into the main app using Koin.
 * 
 * Features (Conversation and Profile) are split into two modules: 
 * - api: defines the public facing routes for this feature
 * - impl: defines the entryProviders for this feature, these are injected into the app's main activity
 * The common module defines:
 * - a common navigator class that exposes a back stack and methods to modify that back stack
 * - a type that should be used by feature modules to inject entryProviders into the app's main activity
 * The app module creates the navigator by supplying a start destination and provides this navigator
 * to the rest of the app module (i.e. MainActivity) and the feature modules.
 */
@OptIn(KoinExperimentalAPI::class)
class KoinModularActivity : ComponentActivity(), AndroidScopeComponent, KoinComponent {
    // Local Koin Context Instance
    companion object {
        private val localKoin = koinApplication {
            modules(appModule)
        }.koin
    }
    // Override default Koin context to use the local one
    override fun getKoin(): Koin = localKoin
    override val scope : Scope by activityRetainedScope()
    val navigator: Navigator by inject()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setEdgeToEdgeConfig()
        navigator.handleDeepLink(intent)
        setContent {
            Scaffold { paddingValues ->
                NavDisplay(
                    backStack = navigator.backStack,
                    modifier = Modifier.padding(paddingValues),
                    onBack = { navigator.goBack() },
                    entryProvider = getEntryProvider()
                )
            }
        }
    }

}
KoinModularActivity.kt

模組化導覽指南 (Koin)

運作方式