Implementing BottomNavigation with nested Fragments.

	<?xml version="1.0" encoding="utf-8"?>
	<android.support.constraint.ConstraintLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	xmlns:tools="http://schemas.android.com/tools"
	xmlns:app="http://schemas.android.com/apk/res-auto"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	tools:context=".MainActivity">

	<FrameLayout
	android:id="@+id/fragment_container"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:layout_marginBottom="56dp"
	android:text="@string/navigation_home"
	app:layout_constraintLeft_toLeftOf="parent"
	app:layout_constraintTop_toTopOf="parent" />

	<android.support.design.widget.BottomNavigationView
	android:id="@+id/navigation"
	android:layout_width="0dp"
	android:layout_height="wrap_content"
	android:background="@color/colorPrimary"
	app:itemIconTint="@color/colorNavIcon"
	app:itemTextColor="@color/colorNavText"
	app:layout_constraintBottom_toBottomOf="parent"
	app:layout_constraintLeft_toLeftOf="parent"
	app:layout_constraintRight_toRightOf="parent"
	app:menu="@menu/navigation" />

	</android.support.constraint.ConstraintLayout>

view raw activity_main.xml hosted with ❤ by GitHub

	apply plugin: 'com.android.application'

	apply plugin: 'kotlin-android'

	apply plugin: 'kotlin-android-extensions'

	android {
	compileSdkVersion 28
	defaultConfig {
	applicationId "swiswiswift.com.swiswiswiftandroid"
	minSdkVersion 15
	targetSdkVersion 28
	versionCode 1
	versionName "1.0"
	testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
	}
	buildTypes {
	release {
	minifyEnabled false
	proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
	}
	}
	}

	dependencies {
	implementation fileTree(dir: 'libs', include: ['*.jar'])
	implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
	implementation 'com.android.support:appcompat-v7:28.0.0'
	implementation 'com.android.support.constraint:constraint-layout:1.1.3'
	testImplementation 'junit:junit:4.12'
	androidTestImplementation 'com.android.support.test:runner:1.0.2'
	androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

	// BottomNavigationView
	implementation 'com.android.support:appcompat-v7:28.0.0'

	// MaterialIcon
	implementation 'com.android.support:design:28.0.0'
	}

view raw build.gradle hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<resources>
	<color name="colorPrimary">#008577</color>
	<color name="colorPrimaryDark">#00574B</color>
	<color name="colorAccent">#D81B60</color>
	<color name="white">#FFF</color>
	<color name="colorNavIcon">#dae9f6</color>
	<color name="colorNavText">#01294b</color>
	</resources>

view raw colors.xml hosted with ❤ by GitHub

	package swiswiswift.com.swiswiswiftandroid

	import android.os.Bundle
	import android.support.v4.app.Fragment
	import android.view.LayoutInflater
	import android.view.View
	import android.view.ViewGroup

	class DashboardFragment : Fragment() {
	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
	return inflater.inflate(R.layout.fragment_dashboard, null)
	}
	}

view raw DashboardFragment.kt hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent">

	<TextView
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_centerHorizontal="true"
	android:layout_centerVertical="true"
	android:text="@string/navigation_dashboard"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

	</RelativeLayout>

view raw fragment_dashboard.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent">

	<TextView
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_centerHorizontal="true"
	android:layout_centerVertical="true"
	android:text="@string/navigation_home"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

	</RelativeLayout>

view raw fragment_home.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent">

	<TextView
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_centerHorizontal="true"
	android:layout_centerVertical="true"
	android:text="@string/navigation_notifications"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

	</RelativeLayout>

view raw fragment_notifications.xml hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent">

	<TextView
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:layout_centerHorizontal="true"
	android:layout_centerVertical="true"
	android:text="@string/navigation_profile"
	android:textAppearance="@style/Base.TextAppearance.AppCompat.Large" />

	</RelativeLayout>

view raw fragment_profile.xml hosted with ❤ by GitHub

	package swiswiswift.com.swiswiswiftandroid

	import android.os.Bundle
	import android.support.v4.app.Fragment
	import android.view.LayoutInflater
	import android.view.View
	import android.view.ViewGroup

	class HomeFragment : Fragment() {
	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
	return inflater.inflate(R.layout.fragment_home, null)
	}
	}

view raw HomeFragment.kt hosted with ❤ by GitHub

	package swiswiswift.com.swiswiswiftandroid

	import android.support.v7.app.AppCompatActivity
	import android.os.Bundle
	import android.support.design.widget.BottomNavigationView
	import android.support.v4.app.Fragment
	import android.view.MenuItem

	class MainActivity : AppCompatActivity(), BottomNavigationView.OnNavigationItemSelectedListener {

	override fun onCreate(savedInstanceState: Bundle?) {
	super.onCreate(savedInstanceState)
	setContentView(R.layout.activity_main)

	//loading the default fragment
	loadFragment(HomeFragment())

	//getting bottom navigation view and attaching the listener
	val navigation = findViewById<BottomNavigationView>(R.id.navigation)
	navigation.setOnNavigationItemSelectedListener(this)
	}

	override fun onNavigationItemSelected(item: MenuItem): Boolean {
	var fragment: Fragment? = null

	when (item.getItemId()) {
	R.id.navigation_home -> fragment = HomeFragment()

	R.id.navigation_dashboard -> fragment = DashboardFragment()

	R.id.navigation_notifications -> fragment = NotificationsFragment()

	R.id.navigation_profile -> fragment = ProfileFragment()
	}

	return loadFragment(fragment)
	}

	private fun loadFragment(fragment: Fragment?): Boolean {
	//switching fragment
	if (fragment != null) {
	supportFragmentManager
	.beginTransaction()
	.replace(R.id.fragment_container, fragment!!)
	.commit()
	return true
	}
	return false
	}
	}

view raw MainActivity.kt hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<menu xmlns:android="http://schemas.android.com/apk/res/android">
	<item
	android:id="@+id/navigation_home"
	android:icon="@drawable/ic_home_black_24dp"
	android:title="@string/navigation_home" />
	<item
	android:id="@+id/navigation_dashboard"
	android:icon="@drawable/ic_dashboard_black_24dp"
	android:title="@string/navigation_dashboard" />
	<item
	android:id="@+id/navigation_notifications"
	android:icon="@drawable/ic_notifications_black_24dp"
	android:title="@string/navigation_notifications" />
	<item
	android:id="@+id/navigation_profile"
	android:icon="@drawable/ic_profile_black_24dp"
	android:title="@string/navigation_profile" />
	</menu>

view raw navigation.xml hosted with ❤ by GitHub

	package swiswiswift.com.swiswiswiftandroid

	import android.os.Bundle
	import android.support.v4.app.Fragment
	import android.view.LayoutInflater
	import android.view.View
	import android.view.ViewGroup

	class NotificationsFragment : Fragment() {
	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
	return inflater.inflate(R.layout.fragment_notifications, null)
	}
	}

view raw NotificationsFragment.kt hosted with ❤ by GitHub

	package swiswiswift.com.swiswiswiftandroid

	import android.os.Bundle
	import android.support.v4.app.Fragment
	import android.view.LayoutInflater
	import android.view.View
	import android.view.ViewGroup

	class ProfileFragment : Fragment() {
	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
	return inflater.inflate(R.layout.fragment_profile, null)
	}
	}

view raw ProfileFragment.kt hosted with ❤ by GitHub

	<resources>
	<string name="app_name">SwiSwiSwiftAndroid</string>
	<string name="navigation_home">Home</string>
	<string name="navigation_dashboard">Dashboard</string>
	<string name="navigation_notifications">Notification</string>
	<string name="navigation_profile">Profile</string>
	</resources>

view raw string.xm hosted with ❤ by GitHub