Migrate from Screen to CinemaxNavigationDestination (#71)

* Implement CinemaxNavigationDestination

* Delete Screen

* Minor improvements

* Add HomeDestination

* Migrate from Screen to CinemaxNavigationDestination

app/src/main/kotlin/com/maximillianleonov/cinemax/presentation/navigation/BottomNavigationSection.kt

@@ -19,29 +19,30 @@ package com.maximillianleonov.cinemax.presentation.navigation
 import androidx.annotation.DrawableRes
 import androidx.annotation.StringRes
 import com.maximillianleonov.cinemax.R
+import com.maximillianleonov.cinemax.feature.home.presentation.navigation.HomeDestination
 
 enum class BottomNavigationSection(
     val route: String,
     @StringRes val stringResourceId: Int,
     @DrawableRes val drawableResourceId: Int
 ) {
     Home(
-        route = Screen.Home.route,
+        route = HomeDestination.route,
         stringResourceId = R.string.home,
         drawableResourceId = R.drawable.ic_home
     ),
     Search(
-        route = Screen.Search.route,
+        route = "search",
         stringResourceId = R.string.search,
         drawableResourceId = R.drawable.ic_search
     ),
     Wishlist(
-        route = Screen.Wishlist.route,
+        route = "wishlist",
         stringResourceId = R.string.wishlist,
         drawableResourceId = R.drawable.ic_heart
     ),
     Settings(
-        route = Screen.Settings.route,
+        route = "settings",
         stringResourceId = R.string.settings,
         drawableResourceId = R.drawable.ic_settings
     )

app/src/main/kotlin/com/maximillianleonov/cinemax/presentation/navigation/CinemaxNavHost.kt

@@ -23,25 +23,28 @@ import androidx.compose.ui.Modifier
 import androidx.navigation.NavHostController
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
-import com.maximillianleonov.cinemax.feature.home.presentation.HomeScreen
+import com.maximillianleonov.cinemax.feature.home.presentation.navigation.HomeDestination
+import com.maximillianleonov.cinemax.feature.home.presentation.navigation.homeGraph
 
 @Suppress("ForbiddenComment")
 @Composable
 fun CinemaxNavHost(
     navController: NavHostController,
     innerPadding: PaddingValues,
-    modifier: Modifier = Modifier
+    modifier: Modifier = Modifier,
+    startDestination: String = HomeDestination.route
 ) {
     NavHost(
         modifier = modifier.padding(paddingValues = innerPadding),
         navController = navController,
-        startDestination = Screen.Home.route
+        startDestination = startDestination
     ) {
-        composable(route = Screen.Home.route) { HomeScreen() }
-        composable(route = Screen.Search.route) { /* TODO: Not yet implemented. */ }
-        composable(route = Screen.Wishlist.route) { /* TODO: Not yet implemented. */ }
-        composable(route = Screen.Settings.route) { /* TODO: Not yet implemented. */ }
-        composable(route = Screen.List.route) { /* TODO: Not yet implemented. */ }
-        composable(route = Screen.Details.route) { /* TODO: Not yet implemented. */ }
+        homeGraph()
+
+        composable(route = "search") { /* TODO: Not yet implemented. */ }
+        composable(route = "wishlist") { /* TODO: Not yet implemented. */ }
+        composable(route = "settings") { /* TODO: Not yet implemented. */ }
+        composable(route = "list") { /* TODO: Not yet implemented. */ }
+        composable(route = "details") { /* TODO: Not yet implemented. */ }
     }
 }

core/core-presentation/src/main/kotlin/com/maximillianleonov/cinemax/core/presentation/navigation/CinemaxNavigationDestination.kt

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2022 Maximillian Leonov
+ *
+ * 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.
+ */
+
+package com.maximillianleonov.cinemax.core.presentation.navigation
+
+/**
+ * An interface for describing the Cinemax navigation destinations.
+ */
+interface CinemaxNavigationDestination {
+    /**
+     * Defines a specific route this destination belongs to.
+     * Route is a String that defines the path to your composable.
+     * You can think of it as an implicit deep link that leads to a specific destination.
+     * Each destination should have a unique route.
+     */
+    val route: String
+
+    /**
+     * Defines a specific destination ID.
+     * This is needed when using nested graphs via the navigation DSL, to differentiate a specific
+     * destination's route from the route of the entire nested graph it belongs to.
+     */
+    val destination: String
+}

features/feature-home/presentation/src/main/kotlin/com/maximillianleonov/cinemax/feature/home/presentation/HomeScreen.kt

@@ -25,12 +25,12 @@ import androidx.compose.ui.Modifier
 import com.maximillianleonov.cinemax.core.presentation.theme.CinemaxTheme
 
 @Composable
-fun HomeScreen() {
-    HomeContent()
+fun HomeRoute(modifier: Modifier = Modifier) {
+    HomeScreen(modifier = modifier)
 }
 
 @Composable
-private fun HomeContent(modifier: Modifier = Modifier) {
+internal fun HomeScreen(modifier: Modifier = Modifier) {
     LazyColumn(
         modifier = modifier.fillMaxSize(),
         verticalArrangement = Arrangement.spacedBy(CinemaxTheme.spacing.extraMedium),

app/src/main/kotlin/com/maximillianleonov/cinemax/presentation/navigation/Screen.kt → features/feature-home/presentation/src/main/kotlin/com/maximillianleonov/cinemax/feature/home/presentation/navigation/HomeDestination.kt

@@ -14,14 +14,16 @@
  * limitations under the License.
  */
 
-package com.maximillianleonov.cinemax.presentation.navigation
+package com.maximillianleonov.cinemax.feature.home.presentation.navigation
 
-sealed class Screen(val route: String) {
-    object Home : Screen(route = "home")
-    object Search : Screen(route = "search")
-    object Wishlist : Screen(route = "wishlist")
-    object Settings : Screen(route = "settings")
+import androidx.navigation.NavGraphBuilder
+import androidx.navigation.compose.composable
+import com.maximillianleonov.cinemax.core.presentation.navigation.CinemaxNavigationDestination
+import com.maximillianleonov.cinemax.feature.home.presentation.HomeRoute
 
-    object List : Screen(route = "list")
-    object Details : Screen(route = "details")
+object HomeDestination : CinemaxNavigationDestination {
+    override val route = "home_route"
+    override val destination = "home_destination"
 }
+
+fun NavGraphBuilder.homeGraph() = composable(route = HomeDestination.route) { HomeRoute() }