Navigation bar snippets

compose/snippets/src/main/java/com/example/compose/snippets/components/Navigation.kt

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+/*
+ * Copyright 2025 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.compose.snippets.components
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Album
+import androidx.compose.material.icons.filled.MusicNote
+import androidx.compose.material.icons.filled.PlaylistAddCircle
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.NavigationBar
+import androidx.compose.material3.NavigationBarDefaults
+import androidx.compose.material3.NavigationBarItem
+import androidx.compose.material3.NavigationRail
+import androidx.compose.material3.NavigationRailItem
+import androidx.compose.material3.PrimaryTabRow
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Tab
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.navigation.NavHostController
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.rememberNavController
+
+@Composable
+fun SongsScreen(modifier: Modifier = Modifier) {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center
+    ) {
+        Text("Songs Screen")
+    }
+}
+
+@Composable
+fun AlbumScreen(modifier: Modifier = Modifier) {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center
+    ) {
+        Text("Album Screen")
+    }
+}
+
+@Composable
+fun PlaylistScreen(modifier: Modifier = Modifier) {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center
+    ) {
+        Text("Playlist Screen")
+    }
+}
+
+enum class Destination(
+    val route: String,
+    val label: String,
+    val icon: ImageVector,
+    val contentDescription: String
+) {
+    SONGS("songs", "Songs", Icons.Default.MusicNote, "Songs"),
+    ALBUM("album", "Album", Icons.Default.Album, "Album"),
+    PLAYLISTS("playlist", "Playlist", Icons.Default.PlaylistAddCircle, "Playlist")
+}
+
+@Composable
+fun AppNavHost(
+    navController: NavHostController,
+    startDestination: Destination,
+    modifier: Modifier = Modifier
+) {
+    NavHost(
+        navController,
+        startDestination = startDestination.route
+    ) {
+        Destination.entries.forEach { destination ->
+            composable(destination.route) {
+                when (destination) {
+                    Destination.SONGS -> SongsScreen()
+                    Destination.ALBUM -> AlbumScreen()
+                    Destination.PLAYLISTS -> PlaylistScreen()
+                }
+            }
+        }
+    }
+}
+
+@Preview()
+// [START android_compose_components_navigationbarexample]
+@Composable
+fun NavigationBarExample(modifier: Modifier = Modifier) {
+    val navController = rememberNavController()
+    val startDestination = Destination.SONGS
+    var selectedDestination by rememberSaveable { mutableIntStateOf(startDestination.ordinal) }
+
+    Scaffold(
+        bottomBar = {
+            NavigationBar(windowInsets = NavigationBarDefaults.windowInsets) {
+                Destination.entries.forEachIndexed { index, destination ->
+                    NavigationBarItem(
+                        selected = selectedDestination == index,
+                        onClick = {
+                            navController.navigate(route = destination.route)
+                            selectedDestination = index
+                        },
+                        icon = {
+                            Icon(
+                                destination.icon,
+                                contentDescription = destination.contentDescription
+                            )
+                        },
+                        label = { Text(destination.label) }
+                    )
+                }
+            }
+        }
+    ) { contentPadding ->
+        AppNavHost(navController, startDestination, modifier = Modifier.padding(contentPadding))
+    }
+}
+// [END android_compose_components_navigationbarexample]
+
+@Preview()
+// [START android_compose_components_navigationrailexample]
+@Composable
+fun NavigationRailExample(modifier: Modifier = Modifier) {
+    val navController = rememberNavController()
+    val startDestination = Destination.SONGS
+    var selectedDestination by rememberSaveable { mutableIntStateOf(startDestination.ordinal) }
+
+    Scaffold { contentPadding ->
+        NavigationRail(modifier = Modifier.padding(contentPadding)) {
+            Destination.entries.forEachIndexed { index, destination ->
+                NavigationRailItem(
+                    selected = selectedDestination == index,
+                    onClick = {
+                        navController.navigate(route = destination.route)
+                        selectedDestination = index
+                    },
+                    icon = {
+                        Icon(
+                            destination.icon,
+                            contentDescription = destination.contentDescription
+                        )
+                    },
+                    label = { Text(destination.label) }
+                )
+            }
+        }
+        AppNavHost(navController, startDestination)
+    }
+}
+// [END android_compose_components_navigationrailexample]
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Preview(showBackground = true)
+// [START android_compose_components_navigationtabexample]
+@Composable
+fun NavigationTabExample(modifier: Modifier = Modifier) {
+    val navController = rememberNavController()
+    val startDestination = Destination.SONGS
+    var selectedDestination by rememberSaveable { mutableIntStateOf(startDestination.ordinal) }
+
+    Scaffold { contentPadding ->
+        PrimaryTabRow(selectedTabIndex = selectedDestination, modifier = Modifier.padding(contentPadding)) {
+            Destination.entries.forEachIndexed { index, destination ->
+                Tab(
+                    selected = selectedDestination == index,
+                    onClick = {
+                        navController.navigate(route = destination.route)
+                        selectedDestination = index
+                    },
+                    text = {
+                        Text(
+                            text = destination.label,
+                            maxLines = 2,
+                            overflow = TextOverflow.Ellipsis
+                        )
+                    }
+                )
+            }
+        }
+        AppNavHost(navController, startDestination)
+    }
+}
+// [END android_compose_components_navigationtabexample]