模块化导航配方 (Hilt)

此方案演示了如何使用 Navigation 3 和 Dagger/Hilt 进行依赖项注入，从而构建多模块应用。目标是创建一个解耦的架构，其中导航在单独的功能模块中定义和实现。

工作原理

该应用分为多个模块：

  • app 模块：这是主应用模块。它会初始化一个通用 Navigator，并从功能模块注入一组 EntryProviderInstaller。然后，它使用这些安装程序为 NavDisplay 构建最终的 entryProvider。

  • common 模块：此模块包含核心导航逻辑，包括：

    • 用于管理返回堆栈的 Navigator 类。
    • 一种 EntryProviderInstaller 类型，该类型是一个函数，功能模块使用该函数将其导航条目贡献给应用的 entryProvider。

  • 功能模块（例如，conversation、profile)：每个功能都拆分为两个子模块：

    • api 模块：定义了该功能的公共 API，包括其导航路线。这样，其他模块便可导航到此功能，而无需了解其实现细节。
    • impl 模块：提供相应功能的实现，包括其可组合项和一个将功能路线映射到其可组合项的 EntryProviderInstaller。然后，使用 Dagger/Hilt 将此安装程序提供给 app 模块。

这种模块化方法可以清晰地分离关注点，从而提高代码库的可伸缩性和可维护性。每个功能都负责自己的导航逻辑，而 app 模块只是将这些部分组合在一起。

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)
}