Jetpack Compose

Bottom Navigation Bar with Jetpack Compose

Bottom Navigation Bar with Jetpack Compose
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Hi Developer in this jetpack compose article we learn about the Bottom navigation bar. We’ve all experienced BottomNavigationBar in numerous apps, like Linkedin, Instagram, Quora, and many more. In this article, we’ll discover how to include bottom navigation to Jetpack Compose. Here’s a look at how it will appear. Also, you can learn in these blog jetpack compose scaffolds and compose navigation.

What is the reason we require the bottom navigation Bar?

  • It allows users to change between different segments or activities effortlessly.
  • It helps the user be aware of the various screens that are available within the application.
  • The user is able to see which screen they are currently viewing.

Learn more on :

  • Knowledge of Jetpack Compose.
  • The knowledge of Scaffolds and Jetpack create.
  • Knowledge of Compose Navigation.

Android compose bottom navigation bar Example.

Bottom Navigation Bar with Jetpack Compose

So let’s start to make an example app for the bottom navigation bar. Create an Android project with jetpack compose activity and build your project. After that, you can add dependency in your Gradle build file.

Step 1: Gradle build Dependencies 

dependencies {
    implementation 'androidx.core:core-ktx:1.6.0'
    implementation 'androidx.appcompat:appcompat:1.3.1'
    implementation 'com.google.android.material:material:1.4.0'
    implementation "androidx.compose.ui:ui:$compose_version"
    implementation "androidx.compose.material:material:$compose_version"
    implementation "androidx.compose.ui:ui-tooling-preview:$compose_version"
    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
    implementation 'androidx.activity:activity-compose:1.3.1'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_version"
    debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"

    implementation "androidx.navigation:navigation-compose:2.4.0-alpha06"
}

after that syn your project to the implementation of dependencies.

 Step 2: Make a Kotlin Class With the Name BottomNavItem

import androidx.compose.ui.graphics.vector.ImageVector

data class BottomNavItem(
    val name: String,
    val route: String,
    val icon: ImageVector,
    val badgeCount: Int = 0
)

Step 3 Implement on Main activity Kotlin Class.

In the bottom nav Item, you can set the tab Name, Icon, Count, and its routes. so let, ‘s make the Bottom navigation bar UI and its tab. In this article, I make 3 tab like Home, Notification, Chat. and its click. See full source code below.

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.*
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Email
import androidx.compose.material.icons.filled.Home
import androidx.compose.material.icons.filled.Notifications
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Alignment.Companion.CenterHorizontally
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.navigation.NavController
import androidx.navigation.NavHostController
import androidx.navigation.compose.NavHost
import androidx.navigation.compose.composable
import androidx.navigation.compose.currentBackStackEntryAsState
import androidx.navigation.compose.rememberNavController
import com.plcoding.bottomnavwithbadges.ui.theme.BottomNavWithBadgesTheme

class MainActivity : ComponentActivity() {
    @ExperimentalMaterialApi
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            BottomNavWithBadgesTheme {
                val navController = rememberNavController()
                Scaffold(
                    bottomBar = {
                        BottomNavigationBar(
                            items = listOf(
                                BottomNavItem(
                                    name = "Home",
                                    route = "home",
                                    icon = Icons.Default.Home
                                ),
                                BottomNavItem(
                                    name = "Notifications",
                                    route = "Notifications",
                                    icon = Icons.Default.Notifications,
                                    badgeCount = 13
                                ),
                                BottomNavItem(
                                    name = "Chat",
                                    route = "chat",
                                    icon = Icons.Default.Email,
                                    badgeCount = 170
                                ),
                            ),
                            navController = navController,
                            onItemClick = {
                                navController.navigate(it.route)
                            }
                        )
                    }
                ) {
                    Navigation(navController = navController)
                }
            }
        }
    }
}

@Composable
fun Navigation(navController: NavHostController) {
    NavHost(navController = navController, startDestination = "home") {
        composable("home") {
            HomeScreen()
        }
        composable("Notifications") {
            NotificationsScreen()
        }
        composable("chat") {
            ChatScreen()
        }
    }
}

@ExperimentalMaterialApi
@Composable
fun BottomNavigationBar(
    items: List<BottomNavItem>,
    navController: NavController,
    modifier: Modifier = Modifier,
    onItemClick: (BottomNavItem) -> Unit
) {
    val backStackEntry = navController.currentBackStackEntryAsState()
    BottomNavigation(
        modifier = modifier,
        backgroundColor = Color.Black,
        elevation = 5.dp
    ) {
        items.forEach { item ->
            val selected = item.route == backStackEntry.value?.destination?.route
            BottomNavigationItem(
                selected = selected,
                onClick = { onItemClick(item) },
                selectedContentColor = Color.White,
                unselectedContentColor = Color.Gray,
                icon = {
                    Column(horizontalAlignment = CenterHorizontally) {
                        if(item.badgeCount > 0) {
                            BadgeBox(
                                badgeContent = {
                                    Text(text = item.badgeCount.toString())
                                }
                            ) {
                                Icon(
                                    imageVector = item.icon,
                                    contentDescription = item.name
                                )
                            }
                        } else {
                            Icon(
                                imageVector = item.icon,
                                contentDescription = item.name
                            )
                        }
                        if(selected) {
                            Text(
                                text = item.name,
                                textAlign = TextAlign.Center,
                                fontSize = 10.sp
                            )
                        }
                    }
                }
            )
        }
    }
}

@Composable
fun HomeScreen() {
    Box(
        modifier = Modifier.fillMaxSize(),
        contentAlignment = Alignment.Center
    ) {
        Text(text = "Home screen")
    }
}

@Composable
fun NotificationsScreen() {
    Box(
        modifier = Modifier.fillMaxSize(),
        contentAlignment = Alignment.Center
    ) {
        Text(text = "Notifications screen")
    }
}

@Composable
fun ChatScreen() {
    Box(
        modifier = Modifier.fillMaxSize(),
        contentAlignment = Alignment.Center
    ) {
        Text(text = "Chat screen")
    }
}

Let’s used this code and run your project and see the output of your UI.

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