模組化導覽食譜 (Hilt)

這項做法示範如何使用 Navigation 3 和 Dagger/Hilt 進行依附元件注入，建構多模組應用程式。目標是建立解耦架構，在個別功能模組中定義及實作導覽功能。

運作方式

應用程式分為多個模組：

  • app 模組：這是主要應用程式模組。這個函式會初始化通用 Navigator，並從功能模組注入一組 EntryProviderInstaller。然後使用這些安裝程式，為 NavDisplay 建構最終 entryProvider。

  • common 模組：這個模組包含核心導覽邏輯，包括：

    • 管理返回堆疊的 Navigator 類別。
    • EntryProviderInstaller 型別，這是功能模組用來將導覽項目提供給應用程式 entryProvider 的函式。

  • 功能模組 (例如 conversation、profile)：每個功能都會分成兩個子模組：

    • api 模組：定義功能的公開 API，包括導覽路徑。這樣一來，其他模組就能導覽至這項功能，而不必瞭解實作詳細資料。
    • impl 模組：提供功能的實作項目，包括可組合函式和 EntryProviderInstaller，可將功能的路徑對應至可組合函式。然後，使用 Dagger/Hilt 將這個安裝程式提供給 app 模組。

這種模組化做法可清楚區隔問題，讓程式碼集更具擴充性和可維護性。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。

package com.example.nav3recipes.modular.hilt

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 dagger.Module
import dagger.Provides
import dagger.hilt.InstallIn
import dagger.hilt.android.components.ActivityRetainedComponent
import dagger.multibindings.IntoSet

// API
object Profile

// IMPLEMENTATION
@Module
@InstallIn(ActivityRetainedComponent::class)
object ProfileModule {

    @IntoSet
    @Provides
    fun provideEntryProviderInstaller() : EntryProviderInstaller = {
        entry<Profile>{
            ProfileScreen()
        }
    }
}

@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
        )
    }
}

package com.example.nav3recipes.modular.hilt

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.runtime.entryProvider
import androidx.navigation3.ui.NavDisplay
import com.example.nav3recipes.ui.setEdgeToEdgeConfig
import dagger.hilt.android.AndroidEntryPoint
import javax.inject.Inject

@AndroidEntryPoint
class HiltModularActivity : ComponentActivity() {

    @Inject
    lateinit var navigator: Navigator

    @Inject
    lateinit var entryProviderScopes: Set<@JvmSuppressWildcards EntryProviderInstaller>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setEdgeToEdgeConfig()
        setContent {
            Scaffold { paddingValues ->
                NavDisplay(
                    backStack = navigator.backStack,
                    modifier = Modifier.padding(paddingValues),
                    onBack = { navigator.goBack() },
                    entryProvider = entryProvider {
                        entryProviderScopes.forEach { builder -> this.builder() }
                    }
                )
            }
        }
    }
}

package com.example.nav3recipes.modular.hilt

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 com.example.nav3recipes.ui.theme.colors
import dagger.Module
import dagger.Provides
import dagger.hilt.InstallIn
import dagger.hilt.android.components.ActivityRetainedComponent
import dagger.multibindings.IntoSet

// API
object ConversationList
data class ConversationDetail(val id: Int) {
    val color: Color
        get() = colors[id % colors.size]
}

// IMPL
@Module
@InstallIn(ActivityRetainedComponent::class)
object ConversationModule {

    @IntoSet
    @Provides
    fun provideEntryProviderInstaller(navigator: Navigator): EntryProviderInstaller =
        {
            entry<ConversationList> {
                ConversationListScreen(
                    onConversationClicked = { conversationDetail ->
                        navigator.goTo(conversationDetail)
                    }
                )
            }
            entry<ConversationDetail> { key ->
                ConversationDetailScreen(key) { navigator.goTo(Profile) }
            }
        }
}

@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")
        }
    }
}

package com.example.nav3recipes.modular.hilt

import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.snapshots.SnapshotStateList
import androidx.navigation3.runtime.EntryProviderScope
import dagger.hilt.android.scopes.ActivityRetainedScoped


typealias EntryProviderInstaller = EntryProviderScope<Any>.() -> Unit

@ActivityRetainedScoped
class Navigator(startDestination: Any) {
    val backStack : SnapshotStateList<Any> = mutableStateListOf(startDestination)

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

    fun goBack(){
        backStack.removeLastOrNull()
    }
}
 
package com.example.nav3recipes.modular.hilt

import dagger.Module
import dagger.Provides
import dagger.hilt.InstallIn
import dagger.hilt.android.components.ActivityRetainedComponent
import dagger.hilt.android.scopes.ActivityRetainedScoped

@Module
@InstallIn(ActivityRetainedComponent::class)
object AppModule {

    @Provides
    @ActivityRetainedScoped
    fun provideNavigator() : Navigator = Navigator(startDestination = ConversationList)
}