Bottom Navigation Bar In Material 3 Android Jetpack Compose

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Introduction

In this article, we will explore how to implement a custom bottom navigation bar in Material 3 Android Jetpack Compose. We will cover the basics of creating a bottom navigation bar and then move on to customizing it to achieve a specific design.

Prerequisites

Before we begin, make sure you have the following setup:

  • Android Studio 2022.1 or later
  • Jetpack Compose 1.2.0 or later
  • Material 3 library

Creating a Basic Bottom Navigation Bar

To create a basic bottom navigation bar, we will use the BottomNavigation component from the Material 3 library. Here's an example of how to do it:

@Composable
fun BottomNavigationExample() {
    BottomNavigation(
        backgroundColor = MaterialTheme.colors.background,
        contentColor = MaterialTheme.colors.onBackground
    ) {
        val navController = rememberNavController()
        val screens = listOf(
            Screen1(navController),
            Screen2(navController),
            Screen3(navController)
        )

        screens.forEachIndexed { index, screen ->
            BottomNavigationItem(
                icon = {
                    Icon(
                        imageVector = screen.icon,
                        contentDescription = screen.title
                    )
                },
                label = {
                    Text(
                        text = screen.title,
                        style = MaterialTheme.typography.bodyMedium
                    )
                },
                selected = navController.currentBackStackEntry?.destination?.route == screen.route,
                onClick = {
                    navController.navigate(screen.route) {
                        popUpTo(navController.graph.startDestinationId) {
                            saveState = true
                        }
                        launchSingleTop = true
                        restoreState = true
                    }
                }
            )
        }
    }
}

This code creates a basic bottom navigation bar with three items. Each item has an icon, a label, and a route associated with it.

Customizing the Bottom Navigation Bar

Now that we have a basic bottom navigation bar, let's customize it to achieve the desired design. We want to add a shadow to the bottom navigation bar and round its corners.

@Composable
fun CustomBottomNavigationExample() {
    Box(
        modifier = Modifier
            .fillMaxWidth()
            .height(56.dp)
            .background(MaterialTheme.colors.background)
            .shadow(4.dp, MaterialTheme.shapes.small)
            .rounded(16.dp)
    ) {
        BottomNavigation(
            backgroundColor = MaterialTheme.colors.background,
            contentColor = MaterialTheme.colors.onBackground
        ) {
            // ... (same code as before)
        }
    }
}

In this code, we use a Box composable to create a container with a shadow and rounded corners. We then place the BottomNavigation component inside this container.

Removing the Little Bar on Top

As you mentioned, when you add a shadow to the bottom navigation bar, a little bar appears on top of it. To remove this bar, we can use the elevation property of the Box composable.

@Composable
fun CustomBottomNavigationExample() {
    Box(
        modifier = Modifier
            .fillMaxWidth()
            .height(56.dp)
            .background(MaterialTheme.colors.background)
            .shadow(4.dp, MaterialTheme.shapes.small)
            .rounded(16.dp)
            .elevation(0.dp)
    ) {
        BottomNavigation(
            backgroundColor = MaterialTheme.colors.background,
            contentColor = MaterialTheme.colors.onBackground
        ) {
            // ... (same code as before)
        }
    }
}

By setting the elevation property to 0, we can remove the little bar on top of the bottom navigation bar.

Conclusion

In this article, we learned how to implement a custom bottom navigation bar in Material 3 Android Jetpack Compose. We covered the basics of creating a bottom navigation bar and then moved on to customizing it to achieve a specific design. We also learned how to remove the little bar on top of the bottom navigation bar by using the elevation property.

Example Use Cases

Here are some example use cases for the custom bottom navigation bar:

  • Creating a bottom navigation bar with a shadow and rounded corners
  • Removing the little bar on top of the bottom navigation bar
  • Customizing the appearance of the bottom navigation bar to match the app's design

Code Snippets

Here are some code snippets that you can use to implement the custom bottom navigation bar:

  • BottomNavigationExample.kt: This code creates a basic bottom navigation bar with three items.
  • CustomBottomNavigationExample.kt: This code customizes the bottom navigation bar to add a shadow and rounded corners.
  • CustomBottomNavigationExampleWithElevation.kt: This code removes the little bar on top of the bottom navigation bar by using the elevation property.

Commit Messages

Here are some example commit messages for the custom bottom navigation bar:

  • "Implement custom bottom navigation bar with shadow and rounded corners"
  • "Remove little bar on top of bottom navigation bar"
  • "Customize appearance of bottom navigation bar to match app's design"

API Documentation

Here is some example API documentation for the custom bottom navigation bar:

  • BottomNavigation: This composable creates a bottom navigation bar with the specified background color and content color.
  • BottomNavigationItem: This composable creates a single item in the bottom navigation bar with the specified icon, label, and route.
  • Box: This composable creates a container with the specified modifier, background color, and elevation.
    Q&A: Implementing a Custom Bottom Navigation Bar in Material 3 Android Jetpack Compose ====================================================================================

Introduction

In our previous article, we explored how to implement a custom bottom navigation bar in Material 3 Android Jetpack Compose. We covered the basics of creating a bottom navigation bar and then moved on to customizing it to achieve a specific design. In this article, we will answer some frequently asked questions about implementing a custom bottom navigation bar.

Q: What are the benefits of using a custom bottom navigation bar?

A: Using a custom bottom navigation bar provides several benefits, including:

  • Customization: You can customize the appearance of the bottom navigation bar to match your app's design.
  • Flexibility: You can add or remove items from the bottom navigation bar as needed.
  • Improved user experience: A custom bottom navigation bar can provide a more intuitive and user-friendly experience for your app's users.

Q: How do I add a shadow to the bottom navigation bar?

A: To add a shadow to the bottom navigation bar, you can use the shadow modifier on the Box composable. Here's an example:

@Composable
fun CustomBottomNavigationExample() {
    Box(
        modifier = Modifier
            .fillMaxWidth()
            .height(56.dp)
            .background(MaterialTheme.colors.background)
            .shadow(4.dp, MaterialTheme.shapes.small)
            .rounded(16.dp)
    ) {
        BottomNavigation(
            backgroundColor = MaterialTheme.colors.background,
            contentColor = MaterialTheme.colors.onBackground
        ) {
            // ... (same code as before)
        }
    }
}

Q: How do I remove the little bar on top of the bottom navigation bar?

A: To remove the little bar on top of the bottom navigation bar, you can set the elevation property of the Box composable to 0. Here's an example:

@Composable
fun CustomBottomNavigationExampleWithElevation() {
    Box(
        modifier = Modifier
            .fillMaxWidth()
            .height(56.dp)
            .background(MaterialTheme.colors.background)
            .shadow(4.dp, MaterialTheme.shapes.small)
            .rounded(16.dp)
            .elevation(0.dp)
    ) {
        BottomNavigation(
            backgroundColor = MaterialTheme.colors.background,
            contentColor = MaterialTheme.colors.onBackground
        ) {
            // ... (same code as before)
        }
    }
}

Q: How do I customize the appearance of the bottom navigation bar?

A: To customize the appearance of the bottom navigation bar, you can use various modifiers and composable functions. Here are some examples:

  • Background color: You can change the background color of the bottom navigation bar by using the background modifier.
  • Content color: You can change the content color of the bottom navigation bar by using the contentColor modifier.
  • Icon size: You can change the size of the icons in the bottom navigation bar by using the iconSize modifier.
  • Label size: You can change the size of the labels in the bottom navigation bar by using the labelSize modifier.

Q: How do I add or remove items from the bottom navigation bar?

A: To add or remove items from the bottom navigation bar, you can use the BottomNavigationItem composable. Here's an example:

@Composable
fun CustomBottomNavigationExample() {
    BottomNavigation(
        backgroundColor = MaterialTheme.colors.background,
        contentColor = MaterialTheme.colors.onBackground
    ) {
        val navController = rememberNavController()
        val screens = listOf(
            Screen1(navController),
            Screen2(navController),
            Screen3(navController)
        )

        screens.forEachIndexed { index, screen ->
            BottomNavigationItem(
                icon = {
                    Icon(
                        imageVector = screen.icon,
                        contentDescription = screen.title
                    )
                },
                label = {
                    Text(
                        text = screen.title,
                        style = MaterialTheme.typography.bodyMedium
                    )
                },
                selected = navController.currentBackStackEntry?.destination?.route == screen.route,
                onClick = {
                    navController.navigate(screen.route) {
                        popUpTo(navController.graph.startDestinationId) {
                            saveState = true
                        }
                        launchSingleTop = true
                        restoreState = true
                    }
                }
            )
        }
    }
}

Q: How do I handle navigation between screens?

A: To handle navigation between screens, you can use the NavController composable. Here's an example:

@Composable
fun CustomBottomNavigationExample() {
    val navController = rememberNavController()
    // ... (same code as before)
}

Conclusion

In this article, we answered some frequently asked questions about implementing a custom bottom navigation bar in Material 3 Android Jetpack Compose. We covered topics such as adding a shadow to the bottom navigation bar, removing the little bar on top, customizing the appearance, adding or removing items, and handling navigation between screens.