This example demonstrates how to create Tab Layout in an Android App using Kotlin.
Step 1 − Create a new project in Android Studio, go to File? New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
Example
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <com.google.android.material.tabs.TabLayout android:id="@+id/tabLayout" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="#1db995"> </com.google.android.material.tabs.TabLayout> <androidx.viewpager.widget.ViewPager android:id="@+id/viewPager" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/tabLayout" android:layout_centerInParent="true" android:layout_marginTop="100dp" tools:layout_editor_absoluteX="8dp" /> </RelativeLayout>
Step 3 − Add the following code to src/MainActivity.kt
import android.os.Bundle import androidx.appcompat.app.AppCompatActivity import androidx.viewpager.widget.ViewPager import com.google.android.material.tabs.TabLayout import com.google.android.material.tabs.TabLayout.OnTabSelectedListener import com.google.android.material.tabs.TabLayout.TabLayoutOnPageChangeListener class MainActivity : AppCompatActivity() { lateinit var tabLayout: TabLayout lateinit var viewPager: ViewPager override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) title = "KotlinApp" tabLayout = findViewById(R.id.tabLayout) viewPager = findViewById(R.id.viewPager) tabLayout.addTab(tabLayout.newTab().setText("Football")) tabLayout.addTab(tabLayout.newTab().setText("Cricket")) tabLayout.addTab(tabLayout.newTab().setText("NBA")) tabLayout.tabGravity = TabLayout.GRAVITY_FILL val adapter = MyAdapter(this, supportFragmentManager, tabLayout.tabCount) viewPager.adapter = adapter viewPager.addOnPageChangeListener(TabLayoutOnPageChangeListener(tabLayout)) tabLayout.addOnTabSelectedListener(object : OnTabSelectedListener { override fun onTabSelected(tab: TabLayout.Tab) { viewPager.currentItem = tab.position } override fun onTabUnselected(tab: TabLayout.Tab) {} override fun onTabReselected(tab: TabLayout.Tab) {} }) } }
Step 4 − Create a new Adapter kotlin class (MyAdapter.kt) and add the following code −
import android.content.Context import androidx.fragment.app.Fragment import androidx.fragment.app.FragmentManager import androidx.fragment.app.FragmentPagerAdapter @Suppress("DEPRECATION") internal class MyAdapter( var context: Context, fm: FragmentManager, var totalTabs: Int ) : FragmentPagerAdapter(fm) { override fun getItem(position: Int): Fragment { return when (position) { 0 -> { Football() } 1 -> { Cricket() } 2 -> { NBA() } else -> getItem(position) } } override fun getCount(): Int { return totalTabs } }
Step 5 − Create 3 Fragment activities (Cricket, Football, NBA - You can have your name) and the following code −
Cricket.kt
import android.os.Bundle import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import androidx.fragment.app.Fragment class Cricket : Fragment() { override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? { // Inflate the layout for this fragment return inflater.inflate(R.layout.fragment_cricket, container, false) } }
fragment_cricket.xml
<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".Cricket"> <!-- TODO: Update blank fragment layout --> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="Cricket Fragment" android:textAlignment="center" android:textSize="16sp" android:textStyle="bold" /> </FrameLayout>
Football.kt
import android.os.Bundle import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import androidx.fragment.app.Fragment class Football : Fragment() { override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? { // Inflate the layout for this fragment return inflater.inflate(R.layout.fragment_football, container, false) } }
fragment_footbal.xml
<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".Football"> <!-- TODO: Update blank fragment layout --> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="Football Fragment" android:textAlignment="center" android:textSize="16sp" android:textStyle="bold" /> </FrameLayout>
NBA.kt
import android.os.Bundle import androidx.fragment.app.Fragment import android.view.LayoutInflater import android.view.View import android.view.ViewGroup class NBA : Fragment() { override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? { // Inflate the layout for this fragment return inflater.inflate(R.layout.fragment_n_b_a, container, false) } }
fragment_n_b_a.xml
<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".NBA"> <!-- TODO: Update blank fragment layout --> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="NBA Fragment" android:textAlignment="center" android:textSize="16sp" android:textStyle="bold" /> </FrameLayout>
Step 6 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="https://schemas.android.com/apk/res/android" package="com.example.q11"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen