Implement deeplink in Nav3

Author: claraf3

JetNews/app/src/main/AndroidManifest.xml

@@ -40,6 +40,14 @@
                     android:pathPrefix="/jetnews"
                     android:scheme="https" />
             </intent-filter>
+            <intent-filter android:autoVerify="true">
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="https"
+                    android:host="developer.android.com"
+                    android:pathPrefix="/jetnews/home" />
+            </intent-filter>
         </activity>
 
         <receiver

JetNews/app/src/main/java/com/example/jetnews/ui/JetnewsApp.kt

@@ -25,8 +25,10 @@ import androidx.compose.material3.windowsizeclass.WindowWidthSizeClass
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.navigation3.runtime.NavKey
 import com.example.jetnews.data.AppContainer
 import com.example.jetnews.ui.components.AppNavRail
+import com.example.jetnews.ui.navigation.Home
 import com.example.jetnews.ui.navigation.JetnewsNavDisplay
 import com.example.jetnews.ui.navigation.NavigationState
 import com.example.jetnews.ui.navigation.Navigator
@@ -35,14 +37,14 @@ import com.example.jetnews.ui.theme.JetnewsTheme
 import kotlinx.coroutines.launch
 
 @Composable
-fun JetnewsApp(appContainer: AppContainer, widthSizeClass: WindowWidthSizeClass) {
+fun JetnewsApp(appContainer: AppContainer, widthSizeClass: WindowWidthSizeClass, deeplinkKey: NavKey?) {
     JetnewsTheme {
         val coroutineScope = rememberCoroutineScope()
 
         val isExpandedScreen = widthSizeClass == WindowWidthSizeClass.Expanded
         val sizeAwareDrawerState = rememberSizeAwareDrawerState(isExpandedScreen)
 
-        val navigationState = rememberNavigationState()
+        val navigationState = rememberNavigationState(deeplinkKey ?: Home())
         val navigator = Navigator(navigationState)
 
         ModalNavigationDrawer(

JetNews/app/src/main/java/com/example/jetnews/ui/MainActivity.kt

@@ -16,13 +16,18 @@
 
 package com.example.jetnews.ui
 
+import android.content.Intent
+import android.net.Uri
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.compose.material3.windowsizeclass.ExperimentalMaterial3WindowSizeClassApi
 import androidx.compose.material3.windowsizeclass.calculateWindowSizeClass
+import androidx.navigation3.runtime.NavKey
 import com.example.jetnews.JetnewsApplication
+import com.example.jetnews.ui.navigation.Home
+import com.example.jetnews.ui.navigation.POST_ID
 
 class MainActivity : ComponentActivity() {
 
@@ -34,7 +39,19 @@ class MainActivity : ComponentActivity() {
         val appContainer = (application as JetnewsApplication).container
         setContent {
             val widthSizeClass = calculateWindowSizeClass(this).widthSizeClass
-            JetnewsApp(appContainer, widthSizeClass)
+            JetnewsApp(appContainer, widthSizeClass, getDeepLinkKey(intent))
         }
     }
 }
+
+private fun getDeepLinkKey(intent: Intent): NavKey? {
+    val uri: Uri = intent.data ?: return null
+    val pathParams = uri.pathSegments
+    if (pathParams.lastOrNull() != "home") return null
+
+    val queryParams = uri.getQueryParameters(POST_ID)
+    if (queryParams.isEmpty() || queryParams.size > 1) return null
+    // "https://developer.android.com/jetnews/home?postId={$POST_ID}"
+    return Home(postId = Uri.decode(queryParams.firstOrNull()))
+}
+

JetNews/app/src/main/java/com/example/jetnews/ui/navigation/JetnewsNavDisplay.kt

@@ -38,7 +38,7 @@ data class Home(val postId: String? = null) : NavKey
 @Serializable
 object Interests : NavKey
 
-val NAVIGATION_KEYS = listOf(Home(), Interests)
+fun getNavigationKeys(startKey: NavKey) = listOf(startKey, Interests)
 
 const val POST_ID = "postId"
 

JetNews/app/src/main/java/com/example/jetnews/ui/navigation/JetnewsNavigation.kt

@@ -32,12 +32,15 @@ import androidx.navigation3.runtime.rememberNavBackStack
 import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
 
 @Composable
-fun rememberNavigationState(startKey: NavKey = Home()): NavigationState {
+fun rememberNavigationState(startKey: NavKey): NavigationState {
     val currentKeys = rememberNavBackStack(startKey)
-    val backStacks = buildMap { NAVIGATION_KEYS.forEach { put(it::class.toString(), rememberNavBackStack(it)) } }.toMutableMap()
-    return remember(startKey) {
-        NavigationState(currentKeys, backStacks)
-    }
+    val backStacks = buildMap {
+        getNavigationKeys(startKey)
+            .forEach {
+                put(it::class.toString(), rememberNavBackStack(it))
+            }
+    }.toMutableMap()
+    return remember(startKey) { NavigationState(currentKeys, backStacks) }
 }
 
 /**