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 stack, pages or slot for your screen configurations
• 📦 rememberOnRoute() lets you retain your view model across configuration changes and gets cleared when the user leaves the screen
• 🚉 Multiplatform! Supports Android, WearOS, Desktop, iOS and Web

At a glance

// Declare your screen configurations as @Serializable for type-safety
@Serializable
sealed class Screen : Parcelable {
  data 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 viewModel: DetailViewModel = rememberOnRoute(key = detail) { // this: RouterContext 
    DetailViewModel(this, detail)
      // Optional, if you want your coroutine scope to be cancelled when the screen is removed from the backstack
      .apply { doOnDestroy { cancel() } }      
  }

  val state: DetailState by viewModel.states.collectAsState()
  
  Text(text = state.detail)
}

class DetailViewModel(context: RouterContext, detail: String): CoroutineScope {
  // Optional, if you want to scope your coroutines to the lifecycle of this screen
  override val coroutineContext: CoroutineContext = Dispatchers.Main + SupervisorJob()
  
  // Optional, if you want your state to survive process death ☠️ 
  // Derive your initial state from [RouterContext.state] 
  private val initialState: DetailState = context.state(DetailState(detail)) { states.value }
  private val stateFlow = MutableStateFlow(initialState)
  
  val states: StateFlow<DetailState> = stateFlow
}

Installation

Decompose-Router is published on Maven Central. Latest version

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

Note - Check for compatible versions of Decompose and Compose in the version catalog

[versions]
decompose-router = "<version>"

[libraries]
# For Jetpack Compose / 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" }

Read more

• Documentation here
• API Reference here

Licence

Copyright 2024 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.