Compose Easy Route 📍

Jetpack Compose navigation made declarative

• Download
• Defining destinations
• Navigation host
• Navigation
• Navigation arguments
• Return result
• Nested graphs
• Deep links
• Android Studio not indexing generated files

Download

repositories {
    ...
    maven("https://jitpack.io")
}

dependencies {
    implementation("com.github.LanarsInc.compose-easy-route:compose-easy-route:{version}")
    implementation("com.github.LanarsInc.compose-easy-route:compose-easy-route-core:{version}")
    ksp("com.github.LanarsInc.compose-easy-route:compose-easy-route-generator:{version}")
}

Defining destinations

To mark a Composable as a destination, use the @Destination annotation:

@Destination(name = "foo-page")
@Composable
fun FooPage() {
    /* */
}

@Destination annotation takes one mandatory parameter:

• name - name of the destination route

Navigation host

EasyRouteNavHost listens to navigation commands and triggers NavController. It uses Compose Navigation's NavHost under the hood. EasyRouteNavHost has three mandatory parameters:

• navigationManager - used for sending navigation commands to EasyRouteNavHost
• navGraph - generated NavigationGraph object from NavGraphs object
• startDestination - initial destination

val navigationManager = rememberNavigationManager()
EasyRouteNavHost(
    navigationManager = navigationManager,
    navGraph = NavGraphs.root,
    startDestination = FirstPageDestination
)

NOTE: Destination can only be used as start if it doesn't have parameters, or has only optional parameters.

Navigation

ComposeEasyRoute navigation API is similar to original Compose Navigation's.

Navigate to a destination

navigationManager.navigate(FooPageDestination())

Navigating with arguments:

navigationManager.navigate(BarPageDestination(id = 42, name = "Name"))

Pop back stack

navigationManager.popBackStack()

Pop up to specific destination:

navigationManager.popBackStack(FooPageDestination)

Pop up to before navigating

navigationManager.navigate(FooPageDestination()) {
    popUpTo(BarPageDestination) { inclusive = true }
}

Pop the whole back stack

navigationManager.navigate(FooPageDestination()) {
    popUntilRoot { inclusive = true }
}

Navigation arguments

To declare navigation arguments you can simply add them to the Composable function:

@Destination(name = "foo-page")
@Composable
fun FooPage(
    id: Int? = null, // <- this will be an optional navigation argument
    name: String // <- this will be a mandatory navigation argument
)

Supported types

• Int
• Float
• Long
• Boolean
• String
• Serializable
• Parcelable
• Enums
• IntArray
• FloatArray
• LongArray
• BooleanArray
• Array<String>
• Array<Serializable>
• Array<Parcelable>

NOTE: ComposeEasyRoute supports passing Serializable and Parcelable objects, however this approach is not recommended by Google. The official documentation says:

Passing complex data structures over arguments is considered an anti-pattern. Each destination should be responsible for loading UI data based on the minimum necessary information, such as item IDs. This simplifies process recreation and avoids potential data inconsistencies.

So you should avoid it as much as you can.

Return result

To return the result to the previous screen use popBackStack with withResult function.

navigationManager.popBackStack {
    withResult(
        key = "key",
        value = value
    )
}

On the screen to where you return the result, observe the result in this way:

LaunchedEffect(true) {
    navigationManager.currentBackStackEntry?.collectResult<YourResultType?>(
	key = "key",
	initialValue = null
    ) { result ->
	// process the result
    }
}

You can return the result not only to the previous screen, but to any destinnation in back stack.

navigationManager.popBackStack(
    destination = FooPageDestination,
    inclusive = false
) {
    withResult(
	key = "key",
	value = value
    )
}

Nested graphs

By default, all your destinations will belong to root NavigationGraph. This NavigationGraph instance will be generated in an object called NavGraphs. So, you can access it via NavGraphs.root and you should pass it into EasyRouteNavHost call.

To define a nested graph, you need to create an annotation class annotated with @NavGraph. For example:

@NavGraph(route = "registration")
annotation class RegistrationNavGraph(
    val start: Boolean = false
)

Note that start parameter is mandatory. It is used to mark destinations as start. Exactly one destination within specific navigation graph must be marked as start.

The @NavGraph annotation takes one mandatory parameter:

• route - the route of the navigation graph

To make destinations part of this navigation graph, you need to annotate them with it:

@RegistrationNavGraph(start = true)
@Destination(name = "foo-page")
@Composable
fun FooPage() {
    /* */
}

By default, all nested graphs are children of the root navigation graph. To define a nested graph as a child of another nested graph, use parent parameter of @NavGraph annotatioon:

@NavGraph(
    route = "confirmation",
    parent = RegistrationNavGraph::class
)
annotation class ConfirmationNavGraph

Multiple NavHosts

Sometimes you want to create another NavHost that is independent from main NavHost (e.g. when implementing bottom navigation or bottom sheet). For that you will need to define a navigation graph, and mark it as independent, so ComposeEasyRoute will know that this navigation graph is separate from main navigation graph. Also, for independent graphs we don't need the start parameter, because startDestination will be passed right into EasyRouteNavHost.

NOTE: Independent graphs can't be defined as children of other graphs.

@NavGraph(
    route = "bottom-navigation",
    independent = true
)
annotation class BottomNavigationGraph

@BottomNavigationNavGraph
@Destination("books")
@Composable
fun BooksScreen() {
    /* */
}

val navigationManager = remember { NavigationManager() }
EasyRouteNavHost(
    navigationManager = navigationManager,
    navGraph = NavGraphs.bottomNavigation, 
    startDestination = BooksScreenDestination
)

Scoping ViewModel to navigation graph

Sometimes its useful to scope ViewModel to a specific navigation graph. ComposeEasyRoute provides a way to do that by obtaining parent backstack entry in Composable through parameter of type NavBackStackEntry, annotated with @ParentBackStackEntry, and passing it to viewModel() function.

@RegistrationNavGraph
@Destination(name = "foo-page")
@Composable
fun FooPage(
    @ParentBackStackEntry parentBackStackEntry: NavBackStackEntry
) {
    val viewModel = viewModel<SharedViewModel>(parentBackStackEntry)
    // if using Hilt
    val hiltViewModel = hiltViewModel<SharedViewModel>(parentBackStackEntry)
    /* */
}

Deep links

You can define deep links to a destination like this:

@Destination(
    name = "foo-page",
    deepLinks = [
        EasyRouteDeepLink(uriPattern = "https://www.example.com/foo/{id}")
    ]
)
@Composable
fun FooPage(id: Int) {
    /* */
}

EasyRouteDeepLink also has action and mimeType parameters. Read more about deep linking in official documentation.

Android Studio not indexing generated files

See KSP related issue.

Fix: put this code inside android block.

applicationVariants.all {
    kotlin.sourceSets {
        getByName(name) {
            kotlin.srcDir("build/generated/ksp/$name/kotlin")
        }
    }
}