add SavedStateHandle.decodeArguments() extension

core/api/core.api

@@ -36,3 +36,7 @@ public final class com/kiwi/navigationcompose/typed/RoutingKt {
 	public static final fun toDeepLinkUri (Lcom/kiwi/navigationcompose/typed/Destination;)Landroid/net/Uri;
 }
 
+public final class com/kiwi/navigationcompose/typed/internal/NavBuilderKt {
+	public static final fun decodeArguments (Landroidx/lifecycle/SavedStateHandle;Lkotlinx/serialization/KSerializer;)Lcom/kiwi/navigationcompose/typed/Destination;
+}
+

core/src/main/kotlin/com/kiwi/navigationcompose/typed/NavBuilder.kt

@@ -1,11 +1,12 @@
 package com.kiwi.navigationcompose.typed
 
-import android.os.Bundle
 import androidx.annotation.MainThread
 import androidx.compose.animation.AnimatedContentTransitionScope
 import androidx.compose.animation.EnterTransition
 import androidx.compose.animation.ExitTransition
 import androidx.compose.runtime.Composable
+import androidx.core.os.bundleOf
+import androidx.lifecycle.SavedStateHandle
 import androidx.navigation.NamedNavArgument
 import androidx.navigation.NavBackStackEntry
 import androidx.navigation.NavDeepLink
@@ -15,7 +16,9 @@ import androidx.navigation.compose.composable
 import androidx.navigation.compose.dialog
 import androidx.navigation.compose.navigation
 import androidx.navigation.navArgument
-import com.kiwi.navigationcompose.typed.internal.UriBundleDecoder
+import com.kiwi.navigationcompose.typed.internal.BundleDataMap
+import com.kiwi.navigationcompose.typed.internal.UriDataDecoder
+import com.kiwi.navigationcompose.typed.internal.decodeArguments
 import com.kiwi.navigationcompose.typed.internal.isNavTypeOptional
 import kotlin.reflect.KClass
 import kotlinx.serialization.ExperimentalSerializationApi
@@ -265,10 +268,14 @@ public fun <T : Destination> decodeArguments(
 ): T {
 	// Arguments may be empty if the destination does not have any parameters,
 	// and it is a start destination.
-	val decoder = UriBundleDecoder(navBackStackEntry.arguments ?: Bundle())
+	val decoder = UriDataDecoder(BundleDataMap(navBackStackEntry.arguments ?: bundleOf()))
 	return decoder.decodeSerializableValue(serializer)
 }
 
+@ExperimentalSerializationApi
+public inline fun <reified T : Destination> SavedStateHandle.decodeArguments(): T =
+	this.decodeArguments(serializer())
+
 @Deprecated(
 	"Deprecated in favor of navigation builder that supports AnimatedContent",
 	level = DeprecationLevel.HIDDEN,

core/src/main/kotlin/com/kiwi/navigationcompose/typed/internal/NavBuilder.kt

@@ -0,0 +1,15 @@
+package com.kiwi.navigationcompose.typed.internal
+
+import androidx.lifecycle.SavedStateHandle
+import com.kiwi.navigationcompose.typed.Destination
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.KSerializer
+
+@ExperimentalSerializationApi
+@PublishedApi
+internal fun <T : Destination> SavedStateHandle.decodeArguments(
+	serializer: KSerializer<T>,
+): T {
+	val decoder = UriDataDecoder(SavedStateDataMap(this))
+	return decoder.decodeSerializableValue(serializer)
+}

core/src/main/kotlin/com/kiwi/navigationcompose/typed/internal/UriBundleDecoder.kt → core/src/main/kotlin/com/kiwi/navigationcompose/typed/internal/UriDataDecoder.kt

@@ -1,6 +1,5 @@
 package com.kiwi.navigationcompose.typed.internal
 
-import android.os.Bundle
 import kotlinx.serialization.DeserializationStrategy
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.descriptors.SerialDescriptor
@@ -10,13 +9,13 @@ import kotlinx.serialization.json.Json
 import kotlinx.serialization.modules.SerializersModule
 
 @ExperimentalSerializationApi
-internal class UriBundleDecoder(
-	private val bundle: Bundle,
+internal class UriDataDecoder(
+	private val data: UriDataMap,
 ) : AbstractDecoder() {
 	override val serializersModule: SerializersModule by lazy { getSerializersModule() }
 
 	private val json by lazy {
-		Json { serializersModule = this@UriBundleDecoder.serializersModule }
+		Json { serializersModule = this@UriDataDecoder.serializersModule }
 	}
 
 	private var root = true
@@ -36,32 +35,32 @@ internal class UriBundleDecoder(
 		while (elementIndex < elementsCount) {
 			elementName = descriptor.getElementName(elementIndex)
 			elementIndex++
-			if (bundle.containsKey(elementName)) {
+			if (data.contains(elementName)) {
 				return elementIndex - 1
 			}
 		}
 		return CompositeDecoder.DECODE_DONE
 	}
 
 	override fun decodeNotNullMark(): Boolean =
-		bundle.containsKey(elementName) && bundle.getString(elementName) != null
+		data.contains(elementName) && data.get(elementName) != null
 
 	override fun decodeNull(): Nothing? = null
 
 	// natively supported
 
-	override fun decodeInt(): Int = bundle.getString(elementName)!!.toInt()
-	override fun decodeLong(): Long = bundle.getString(elementName)!!.toLong()
-	override fun decodeFloat(): Float = bundle.getString(elementName)!!.toFloat()
-	override fun decodeBoolean(): Boolean = bundle.getString(elementName)!!.toBooleanStrict()
-	override fun decodeString(): String = bundle.getString(elementName)!!
+	override fun decodeInt(): Int = data.get(elementName)!!.toInt()
+	override fun decodeLong(): Long = data.get(elementName)!!.toLong()
+	override fun decodeFloat(): Float = data.get(elementName)!!.toFloat()
+	override fun decodeBoolean(): Boolean = data.get(elementName)!!.toBooleanStrict()
+	override fun decodeString(): String = data.get(elementName)!!
 
 	// delegated to other primitives
 
-	override fun decodeDouble(): Double = bundle.getString(elementName)!!.toDouble()
-	override fun decodeByte(): Byte = bundle.getString(elementName)!!.toByte()
-	override fun decodeShort(): Short = bundle.getString(elementName)!!.toShort()
-	override fun decodeChar(): Char = bundle.getString(elementName)!![0]
+	override fun decodeDouble(): Double = data.get(elementName)!!.toDouble()
+	override fun decodeByte(): Byte = data.get(elementName)!!.toByte()
+	override fun decodeShort(): Short = data.get(elementName)!!.toShort()
+	override fun decodeChar(): Char = data.get(elementName)!![0]
 
 	override fun decodeEnum(enumDescriptor: SerialDescriptor): Int = decodeInt()
 

core/src/main/kotlin/com/kiwi/navigationcompose/typed/internal/UriDataMap.kt

@@ -0,0 +1,23 @@
+package com.kiwi.navigationcompose.typed.internal
+
+import android.os.Bundle
+import androidx.lifecycle.SavedStateHandle
+
+internal interface UriDataMap {
+	fun contains(key: String): Boolean
+	fun get(key: String): String?
+}
+
+internal class BundleDataMap(
+	private val bundle: Bundle,
+) : UriDataMap {
+	override fun contains(key: String): Boolean = bundle.containsKey(key)
+	override fun get(key: String): String? = bundle.getString(key)
+}
+
+internal class SavedStateDataMap(
+	private val savedStateHandle: SavedStateHandle,
+) : UriDataMap {
+	override fun contains(key: String): Boolean = savedStateHandle.contains(key)
+	override fun get(key: String): String? = savedStateHandle[key]
+}

core/src/test/kotlin/com/kiwi/navigationcompose/typed/internal/UriBundleDecoderTest.kt → core/src/test/kotlin/com/kiwi/navigationcompose/typed/internal/UriDataDecoderTest.kt

@@ -16,7 +16,7 @@ import org.robolectric.RobolectricTestRunner
 
 @OptIn(ExperimentalSerializationApi::class)
 @RunWith(RobolectricTestRunner::class)
-internal class UriBundleDecoderTest {
+internal class UriDataDecoderTest {
 	@Suppress("unused")
 	@Serializable
 	class TestData(
@@ -53,7 +53,7 @@ internal class UriBundleDecoderTest {
 			"o" to "\"14\"",
 		)
 
-		val decoder = UriBundleDecoder(bundle)
+		val decoder = UriDataDecoder(BundleDataMap(bundle))
 		val data = decoder.decodeSerializableValue(serializer<TestData>())
 
 		Assert.assertEquals(1, data.a)

demo/src/main/kotlin/com/kiwi/navigationcompose/typed/demo/screens/Demo.kt

@@ -6,6 +6,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material3.Divider
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -14,14 +15,22 @@ import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.createSavedStateHandle
+import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.lifecycle.viewmodel.viewModelFactory
+import com.kiwi.navigationcompose.typed.decodeArguments
 import com.kiwi.navigationcompose.typed.demo.HomeDestinations
+import kotlinx.serialization.ExperimentalSerializationApi
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 internal fun Demo(
 	args: HomeDestinations.Demo,
 	onNavigateUp: () -> Unit,
 ) {
+	val viewModel = viewModel<StateDemoViewModel>(factory = ViewModelFactory)
 	Scaffold(
 		topBar = {
 			TopAppBar(
@@ -43,6 +52,21 @@ internal fun Demo(
 			Text(
 				text = args.toString(),
 			)
+			Divider()
+			Text(
+				text = viewModel.arguments.toString(),
+			)
 		}
 	}
 }
+
+internal val ViewModelFactory = viewModelFactory {
+	addInitializer(StateDemoViewModel::class) { StateDemoViewModel(createSavedStateHandle()) }
+}
+
+internal class StateDemoViewModel(
+	state: SavedStateHandle,
+) : ViewModel() {
+	@OptIn(ExperimentalSerializationApi::class)
+	val arguments = state.decodeArguments<HomeDestinations.Demo>()
+}

readme.md

@@ -111,6 +111,36 @@ private fun Home(
 }
 ```
 
+### ViewModel
+
+You can pass your destination arguments directly from the UI using parameters/the assisted inject feature.
+
+For example, in Koin:
+
+```kotlin
+val KoinModule = module {
+	viewModelOf(::DemoViewModel)
+}
+
+fun DemoScreen(arguments: HomeDestinations.Demo) {
+	val viewModel = getViewModel<DemoViewModel> { parametersOf(arguments) }
+}
+
+class DemoViewModel(
+	arguments: HomeDestinations.Demo,
+)
+```
+
+Alternatively, you can read your destination from a `SavedStateHandle` instance:
+
+```kotlin
+class DemoViewModel(
+	state: SavedStateHandle,
+) : ViewModel() {
+	val arguments = state.decodeArguments<HomeDestinations.Demo>()
+}
+```
+
 ### Extensibility
 
 What about cooperation with Accompanist's Material `bottomSheet {}` integration? Do not worry. Basically, all the functionality is just a few simple functions. Create your own abstraction and use `createRoutePattern()`, `createNavArguments()`, `decodeArguments()` and `registerDestinationType()` functions.