Decompose Router

A Compose-multiplatform navigation library that leverage Decompose to create an API inspired by Conductor

A detailed breakdown available in this Medium article

Features

🚏 A Router that manages a FILO stack for your screen configurations
📦 rememberOnRoute() lets you retain your view model across configuration changes and gets cleared when the user leaves the screen
☠️ A SavedStateHandle to restore state gracefully after the process death. (for Android)
🚉 Multiplatform! Supports Android, WearOS, Desktop, iOS and Web

Adding to your project

Decompose-Router is published on Maven Central

repositories {
  mavenCentral()
  // or for snapshot builds
  maven("https://s01.oss.sonatype.org/content/repositories/snapshots/")
}

Include the dependency in commonMain. Latest version

Note Check for compatible versions of Compose Multiplatform, Decompose and Essenty in the Version Catalog

1. With version catalog

libs.version.toml

[versions]
# Check in gradle/libs.versions.toml

[libraries]
# For Compose Multiplatform
decompose-router = { module = "io.github.xxfast:decompose-router", version.ref = "decompose-router" }

# For Compose Wear
decompose-router-wear = { module = "io.github.xxfast:decompose-router-wear", version.ref = "decompose-router" }

# You will need to also bring in decompose and essenty
decompose = { module = "com.arkivanov.decompose:decompose", version.ref = "decompose" }
decompose-compose-multiplatform = { module = "com.arkivanov.decompose:extensions-compose-jetbrains", version.ref = "decompose" }
essenty-parcelable = { module = "com.arkivanov.essenty:parcelable", version.ref = "essenty" }

build.gradle.kts

sourceSets {
  // For Compose Multiplatform
  val commonMain by getting { 
    dependencies { 
      implementation(libs.decompose.router)
      
      // You will probably need to also bring in decompose and essenty
      implementation(libs.decompose)
      implementation(libs.decompose.compose.multiplatform)
      implementation(libs.essenty.parcelable)
    } 
  }
  
  // For Compose Wear
  val androidMain by getting {
    dependencies { 
      implementation(libs.decompose.router.wear)
    } 
  }
}

2. Without version catalog

build.gradle.kts

sourceSets {
  // For Compose Multiplatform
  val commonMain by getting {
    dependencies {
      implementation("io.github.xxfast:decompose-router:${versions.decompose-router}")

      // You will need to also bring in decompose and essenty
      implementation("com.arkivanov.decompose:decompose:${versions.decompose}")
      implementation("com.arkivanov.decompose:extensions-compose-jetbrains:${versions.decompose}")
      implementation("com.arkivanov.essenty:parcelable:${versions.essenty}")
    }
  }

  // For Compose Wear
  val androidMain by getting {
    dependencies {
      implementation("io.github.xxfast:decompose-router-wear:${versions.decompose-router}")
    }
  }
}

At a glance

// Declare your screen configurations for type-safety
@Parcelize
sealed class Screen: Parcelable {
  object List : Screen()
  data class Details(val detail: String) : Screen()
}

@Composable
fun ListDetailScreen() {
  // Create a router with a stack of screen configurations 🚏
  val router: Router<Screen> = rememberRouter { listOf(List) }

  // Hoist your screens for each configuration 🏗️
  RoutedContent(router = router) { screen ->
    when (screen) {
      List -> ListScreen(
        // Navigate by pushing new configurations on the router 🧭
        onSelectItem = { detail -> router.push(detail) } 
      )
      
      is Details -> DetailsScreen(screen.detail)
    }
  }
}

@Composable
fun DetailsScreen(detail: String) {
  // 📦 Scope an instance (a view model, a state-holder or whatever) to a route with [rememberOnRoute] 
  // This makes your instances survive configuration changes (on android) 🔁
  // And holds-on the instance as long as it is in the backstack 🔗
  // Pass in key if you want to reissue a new instance when key changes 🔑 (optional) 
  val instance: DetailInstance = rememberOnRoute(key = detail) { savedState -> DetailInstance(savedState, detail) }
  
  val state: DetailState by instance.states.collectAsState()
  Text(text = state.detail)
}

// If you want your state to survive process death ☠️ derive your initial state from [SavedStateHandle] 
class DetailInstance(savedState: SavedStateHandle, detail: String) : InstanceKeeper.Instance {
  private val initialState: DetailState = savedState.get() ?: DetailState(detail)
  private val stateFlow = MutableStateFlow(initialState)
  val states: StateFlow<DetailState> = stateFlow
}

Platform configurations 🚉

Android / WearOS

build.gradle.kts

class MainActivity : ComponentActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val rootRouterContext: RouterContext = defaultRouterContext()
    setContent {
      CompositionLocalProvider(LocalRouterContext provides rootRouterContext) {
        MaterialTheme {
          ListDetailScreen()
        }
      }
    }
  }
}

Desktop

build.gradle.kts

fun main() {
  val lifecycle = LifecycleRegistry()
  val rootRouterContext = RouterContext(lifecycle = lifecycle)
  
  application {
    Window {
      CompositionLocalProvider(LocalRouterContext provides rootRouterContext) {
        MaterialTheme {
          ListDetailScreen()
        }
      }
    }
  }
}

iOS

Make sure to create your root router context outside of ComposeUIViewController's composable lambda and pass it in to LocalRouterContext

build.gradle.kts

fun MainUIController(rootRouterContext: RouterContext): UIViewController = ComposeUIViewController {
  CompositionLocalProvider(LocalRouterContext provides rootRouterContext) {
    MaterialTheme {
      ListDetailScreen()
    }
  }
}

[!IMPORTANT] You will need to tie root RouterContext's lifecycle to an AppDelegate. See example kotlin app delegate here, or swift delegate here. Read more on the docs here

Web

See example here, or read more on docs here

build.gradle.kts

fun main() {
  onWasmReady {
    val rootRouterContext: RouterContext = defaultRouterContext()

    BrowserViewportWindow(..) {
      CompositionLocalProvider(LocalRouterContext provides rootRouterContext) {
        MaterialTheme {
          ListDetailScreen()
        }
      }
    }
  }
}

Licence

Copyright 2023 Isuru Rajapakse

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.

gabriellcosta / decompose-router Goto Github PK