BottomNavigationView in Android

Last Updated : 16 Aug, 2022

BottomNavigationView makes it easy for users to explore and switch between top-level views with a single tap. There should be a minimum of 3 top-level views and a maximum of 5. If Destinations are more than 5 then use the Navigation Drawer. When the user taps on the icon it will change the top-level view accordingly. In a Music Player app to switch between Home, Album, and Radio, it can be used. Google plus app uses this widget to switch between different views. Instagram uses BottomNavigationView to switch between Feeds, Search, add, Like, and Profile. This is how a BottomNavigationView looks like.

Some Advantages and Disadvantages of BottomNavigationView are: Advantages

It is a Top-level destination that can be accessed from anywhere in the app.
It is a Material Design Component.
Easy to use and implement.

Disadvantages

It is used only when we have only three to five Destinations.
Can only be used with Mobile and Tablets.
The length of Text Labels should be less.
It should be used when the user will spend more than 90% of the time in an app in the same window.
Using with TabLayout may cause confusion to the user.

Step by Step Implementation Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. The code for that has been given in both Java and Kotlin Programming Language for Android.

Step 2: Adding Dependency to the build.gradle File

Add the support library in the build.gradle file and add a dependency in the dependencies section. This library has the inbuilt widget for the Bottom Navigation view so through this library it can be directly added.

implementation 'com.google.android.material:material:1.3.0-alpha03'

Step 3: Working with the XML Files

Now create a new Android Resource Directory. Right-click on the res folder and select Android Resource Directory. Make sure to select the resource type as a menu. Now create the bottom_menu.xml file and add the following code. In this file, we add the title, id, and icon of our menu for BottomNavigationView. Below is the code for the bottom_menu.xml file.

XML

<?xml version="1.0" encoding="utf-8"?> 
<menu xmlns:android="http://schemas.android.com/apk/res/android"> 
  
    <item
        android:id="@+id/algorithm"
        android:icon="@drawable/ic_algorithm"
        android:title="Algorithm" /> 
  
    <item
        android:id="@+id/course"
        android:icon="@drawable/ic_course"
        android:title="Course" /> 
  
    <item
        android:id="@+id/profile"
        android:icon="@drawable/ic_account"
        android:title="Profile" /> 
</menu>

Create an AlgorithmFragment by right click on the java package, selecting new -> Fragment(Blank).

Follow the above steps for CourseFragment and LoginFragment. Now add the following code in the AlgorithmFragment.xml file. Here a TextView is added to the layout. Below is the code for the fragment_algorithm.xml file.

XML

<?xml version="1.0" encoding="utf-8"?> 
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Fragments.AlgorithmFragment"> 
  
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Algorithm"
        android:textSize="30sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 
</androidx.constraintlayout.widget.ConstraintLayout>

Now add the following code in the CourseFragment.xml file.

Here a TextView is added to the layout. Below is the code for the fragment_course.xml file.

XML

<?xml version="1.0" encoding="utf-8"?> 
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Fragments.AlgorithmFragment"> 
  
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Course"
        android:textSize="30sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 
</androidx.constraintlayout.widget.ConstraintLayout>

Now add the following code in the fragment_profile.xml file.

Here a TextView is added to the layout. Below is the code for the fragment_profile.xml file.

XML

<?xml version="1.0" encoding="utf-8"?> 
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Fragments.AlgorithmFragment"> 
  
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Algorithm"
        android:textSize="30sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" /> 
</androidx.constraintlayout.widget.ConstraintLayout>

Now add the following code in the activity_main.xml file. In this file, we add BottomNavigationView to our layout.

XML

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"> 
  
    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/bottom_navigation" /> 
  
    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_gravity="bottom"
        android:background="@color/colorPrimary"
        app:itemIconTint="@android:color/white"
        app:itemTextColor="@android:color/white"
        app:menu="@menu/bottom_menu" /> 
</RelativeLayout>

Step 4: Working with the MainActivity File

Go to the MainActivity File and refer to the following code. Below is the code for the MainActivity File. Comments are added inside the code to understand the code in more detail. In this file, we add OnNavigationItemSelectedListener which helps to navigate between the fragments. It will switch the fragment when the user taps on the icon.

Java

import android.os.Bundle; 
import androidx.appcompat.app.AppCompatActivity; 
import androidx.fragment.app.Fragment; 
import com.google.android.material.bottomnavigation.BottomNavigationView; 
  
public class MainActivity extends AppCompatActivity { 
  
    @Override
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
  
        BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation); 
        bottomNav.setOnNavigationItemSelectedListener(navListener); 
  
        // as soon as the application opens the first 
        // fragment should be shown to the user 
        // in this case it is algorithm fragment 
        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new AlgorithmFragment()).commit(); 
    } 
  
    private final BottomNavigationView.OnNavigationItemSelectedListener navListener = item -> { 
        // By using switch we can easily get 
        // the selected fragment 
        // by using there id. 
        Fragment selectedFragment = null; 
        int itemId = item.getItemId(); 
        if (itemId == R.id.algorithm) { 
            selectedFragment = new AlgorithmFragment(); 
        } else if (itemId == R.id.course) { 
            selectedFragment = new CourseFragment(); 
        } else if (itemId == R.id.profile) { 
            selectedFragment = new ProfileFragment(); 
        } 
        // It will help to replace the  
        // one fragment to other. 
        if (selectedFragment != null) { 
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, selectedFragment).commit(); 
        } 
        return true; 
    }; 
}

Kotlin

import android.os.Bundle 
import androidx.appcompat.app.AppCompatActivity 
import androidx.fragment.app.Fragment 
import com.google.android.material.bottomnavigation.BottomNavigationView 
  
class MainActivity : AppCompatActivity() { 
    override fun onCreate(savedInstanceState: Bundle?) { 
        super.onCreate(savedInstanceState) 
        setContentView(R.layout.activity_main) 
  
        val bottomNav = findViewById<BottomNavigationView>(R.id.bottom_navigation) 
        bottomNav.setOnNavigationItemSelectedListener(navListener) 
  
        // as soon as the application opens the first fragment should 
        // be shown to the user in this case it is algorithm fragment 
        supportFragmentManager.beginTransaction().replace(R.id.fragment_container, AlgorithmFragment()).commit() 
    } 
  
    private val navListener = BottomNavigationView.OnNavigationItemSelectedListener { 
        // By using switch we can easily get the 
        // selected fragment by using there id 
        lateinit var selectedFragment: Fragment 
        when (item.itemId) { 
            R.id.algorithm -> { 
                selectedFragment = AlgorithmFragment() 
            } 
            R.id.course -> { 
                selectedFragment = CourseFragment() 
            } 
            R.id.profile -> { 
                selectedFragment = ProfileFragment() 
            } 
        } 
        // It will help to replace the 
        // one fragment to other. 
        supportFragmentManager.beginTransaction().replace(R.id.fragment_container, selectedFragment).commit() 
            true
    } 
}

Output:

madhavmaheshwarimm20

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Android ListView in Kotlin

BottomNavigationView in Android

XML

XML

XML

XML

XML

Java

Kotlin

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