[Jetsnack] Implement Navigation Library

Jetsnack/app/build.gradle

@@ -91,6 +91,7 @@ dependencies {
     implementation Libs.AndroidX.coreKtx
     implementation Libs.AndroidX.Activity.activityCompose
     implementation Libs.AndroidX.Lifecycle.viewModelCompose
+    implementation Libs.AndroidX.Navigation.navigationCompose
     implementation Libs.AndroidX.ConstraintLayout.constraintLayoutCompose
 
     implementation Libs.AndroidX.Compose.runtime

Jetsnack/app/src/androidTest/java/com/example/jetsnack/AppTest.kt

@@ -16,7 +16,6 @@
 
 package com.example.jetsnack
 
-import androidx.activity.OnBackPressedDispatcher
 import androidx.compose.ui.test.assertIsDisplayed
 import androidx.compose.ui.test.junit4.createAndroidComposeRule
 import androidx.compose.ui.test.onNodeWithText
@@ -35,7 +34,7 @@ class AppTest {
     @Before
     fun setUp() {
         composeTestRule.setContent {
-            JetsnackApp(OnBackPressedDispatcher())
+            JetsnackApp()
         }
     }
 
@@ -62,6 +61,12 @@ class AppTest {
 
         // Navigate to Profile
         composeTestRule.onNodeWithText("PROFILE").performClick().assertIsDisplayed()
-        composeTestRule.onNodeWithText("Profile").assertIsDisplayed()
+        composeTestRule.onNodeWithText("This is currently work in progress").assertIsDisplayed()
+    }
+
+    @Test
+    fun app_canNavigateToDetailPage() {
+        composeTestRule.onNodeWithText("Chips").performClick()
+        composeTestRule.onNodeWithText("Lorem ipsum", substring = true).assertIsDisplayed()
     }
 }

Jetsnack/app/src/main/java/com/example/jetsnack/ui/JetsnackApp.kt

@@ -16,36 +16,19 @@
 
 package com.example.jetsnack.ui
 
-import androidx.activity.OnBackPressedDispatcher
-import androidx.compose.animation.Crossfade
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.saveable.rememberSaveable
-import com.example.jetsnack.ui.home.Home
-import com.example.jetsnack.ui.snackdetail.SnackDetail
+import androidx.navigation.compose.rememberNavController
 import com.example.jetsnack.ui.theme.JetsnackTheme
-import com.example.jetsnack.ui.utils.Navigator
 import com.google.accompanist.insets.ProvideWindowInsets
 
 @Composable
-fun JetsnackApp(backDispatcher: OnBackPressedDispatcher) {
-    val navigator: Navigator<Destination> = rememberSaveable(
-        saver = Navigator.saver(backDispatcher)
-    ) {
-        Navigator(Destination.Home, backDispatcher)
-    }
-    val actions = remember(navigator) { Actions(navigator) }
+fun JetsnackApp() {
     ProvideWindowInsets {
         JetsnackTheme {
-            Crossfade(navigator.current) { destination ->
-                when (destination) {
-                    Destination.Home -> Home(actions.selectSnack)
-                    is Destination.SnackDetail -> SnackDetail(
-                        snackId = destination.snackId,
-                        upPress = actions.upPress
-                    )
-                }
-            }
+            val navController = rememberNavController()
+            JetsnackNavGraph(
+                navController = navController
+            )
         }
     }
 }

Jetsnack/app/src/main/java/com/example/jetsnack/ui/JetsnackNavGraph.kt

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * 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
+ *
+ *     https://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.
+ */
+
+package com.example.jetsnack.ui
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.navigation.NavHostController
+import androidx.navigation.NavType
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.navArgument
+import androidx.navigation.compose.navigate
+import androidx.navigation.compose.rememberNavController
+import com.example.jetsnack.ui.MainDestinations.SNACK_ID_KEY
+import com.example.jetsnack.ui.home.Home
+import com.example.jetsnack.ui.snackdetail.SnackDetail
+
+/**
+ * Destinations used in the ([JetsnackApp]).
+ */
+object MainDestinations {
+    const val HOME_ROUTE = "home"
+    const val SNACK_DETAIL_ROUTE = "snack"
+    const val SNACK_ID_KEY = "snackId"
+}
+
+@Composable
+fun JetsnackNavGraph(
+    navController: NavHostController = rememberNavController(),
+    startDestination: String = MainDestinations.HOME_ROUTE
+) {
+    val actions = remember(navController) { MainActions(navController) }
+    NavHost(
+        navController = navController,
+        startDestination = startDestination
+    ) {
+        composable(MainDestinations.HOME_ROUTE) {
+            Home(
+                onSnackSelected = actions.navigateToSnackDetail
+            )
+        }
+        composable(
+            "${MainDestinations.SNACK_DETAIL_ROUTE}/{$SNACK_ID_KEY}",
+            arguments = listOf(navArgument(SNACK_ID_KEY) { type = NavType.LongType })
+        ) { backStackEntry ->
+            val arguments = requireNotNull(backStackEntry.arguments)
+            val snackId = arguments.getLong(SNACK_ID_KEY)
+            SnackDetail(
+                snackId = snackId,
+                upPress = actions.upPress
+            )
+        }
+    }
+}
+
+/**
+ * Models the navigation actions in the app.
+ */
+class MainActions(navController: NavHostController) {
+    val navigateToSnackDetail: (Long) -> Unit = { snackId: Long ->
+        navController.navigate("${MainDestinations.SNACK_DETAIL_ROUTE}/$snackId")
+    }
+    val upPress: () -> Unit = {
+        navController.navigateUp()
+    }
+}

Jetsnack/app/src/main/java/com/example/jetsnack/ui/MainActivity.kt

@@ -35,7 +35,7 @@ class MainActivity : ComponentActivity() {
         setContent {
             val systemUiController = remember { SystemUiController(window) }
             CompositionLocalProvider(LocalSysUiController provides systemUiController) {
-                JetsnackApp(onBackPressedDispatcher)
+                JetsnackApp()
             }
         }
     }

Jetsnack/buildSrc/src/main/java/com/example/jetsnack/buildsrc/Dependencies.kt

@@ -71,6 +71,10 @@ object Libs {
                 "androidx.lifecycle:lifecycle-viewmodel-compose:1.0.0-alpha05"
         }
 
+        object Navigation {
+            const val navigationCompose = "androidx.navigation:navigation-compose:1.0.0-alpha10"
+        }
+
         object ConstraintLayout {
             const val constraintLayoutCompose =
                 "androidx.constraintlayout:constraintlayout-compose:1.0.0-alpha07"