In this article, we will learn how to create android ViewPager programmatically in Kotlin. We will go through various steps that explains how to create ViewPager and add it in kotlin file, use different attributes to customise it etc. in any android application. For example, how to set visibility of ViewPager programmatically, how to set id of ViewPager, how to set background of ViewPager dynamically etc. We will get answer to all such questions in this post.

Learn to use Different Attributes of ViewPager in XML File to Customize it.

Output

Tutorialwing Kotlin ViewPager Output

Getting Started

We can define android ViewPager widget as below –

ViewPager is layout manager that allows the user to flip left and right through different pages.

Now, how do we use ViewPager in android application ?

Before we move ahead, we need to setup for viewBinding to access ViewPager in Kotlin file without using findViewById() method.

Setup ViewBinding

Add viewBinding true in app/build.gradle file.

 
 android { 
 	// OTHER CODE... 
 	buildFeatures { 
 		viewBinding true 
 	} 
 } 
 

Now, set content in activity using view binding.
Open MainActivity.kt file and write below code in it.

 
 class MainActivity : AppCompatActivity() { 
 	
 	private lateinit var binding: ActivityMainBinding 
 	
 	override fun onCreate(savedInstanceState: Bundle?) { 
 		super.onCreate(savedInstanceState) 
 		binding = ActivityMainBinding.inflate(layoutInflater) 
 		val view = binding.root 
 		setContentView(view) 
 	} 
 } 
 

Now, we can access view in Kotlin file without using findViewById() method.

Since we have a new project, we will modify the xml and class file to use ViewPager programmatically in kotlin. Please follow the steps below.

Modify Values Folder

Open res/values/strings.xml file. Add below code into it.

<resources>
    <string name="app_name">DynamicViewPager</string>
    <string name="no_image">No Image</string>
    <string name="tutorial_by">Tutorial By Tutorialwing.com</string>
    <string name="first_fragment">First Fragment</string>
    <string name="second_fragment">Second Fragment</string>
    <string name="third_fragment">Third Fragment</string>
</resources>

Other values folders have not been changed. So, we are not going to mention it here.

Create Fragment Pages to be used in the viewPager

In this application, we will use three pages in viewPager. So, we need to create three fragment and it’s xml file. Visit Below links to create those fragments.

(1) FirstFragment.kt and first_fragment.xml file
(2) SecondFragment.kt and second_fragment.xml file
(3) ThirdFragment.kt and third_fragment.xml file

We are moving ahead considering we have already created fragments to be used in viewPager.

Create PagerAdapter for ViewPager

We have already covered how to Create PagerAdapter For ViewPager . So, visit link to know more. Here, we will directly use in our project.

Modify Layout Folder

Open res/layout/activity_main.xml file. Add below code into it.

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout 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">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <com.google.android.material.tabs.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/purple_500"
            app:tabGravity="fill"
            app:tabMode="fixed" />

    </com.google.android.material.appbar.AppBarLayout>

    <LinearLayout
        android:id="@+id/rootContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    </LinearLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

Note that LinearLayout has id rootContainer. In Kotlin file, we will create ViewPager Dynamically and add it into this LinearLayout having id rootContainer.

Create Android ViewPager programmatically in Kotlin

Open src/main/java/com.tutorialwing.dynamicviewpager/MainActivity.kt file. Then, add below code into it.

package com.tutorialwing.dynamicviewpager

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.viewpager.widget.ViewPager
import com.tutorialwing.dynamicviewpager.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

	private lateinit var binding: ActivityMainBinding

	override fun onCreate(savedInstanceState: Bundle?) {
		super.onCreate(savedInstanceState)
		binding = ActivityMainBinding.inflate(layoutInflater)
		val view = binding.root
		setContentView(view)

		setupViewPager()
	}

	private fun setupViewPager() {
		val viewPager = ViewPager(this)
		viewPager.id = R.id.viewPager_ID
		viewPager.adapter = ViewPagerAdapter(supportFragmentManager)
		binding.rootContainer.addView(viewPager)

		binding.tabLayout.setupWithViewPager(viewPager)
	}
}

Finally, when you run the application, you will get output as shown above.

Tutorialwing Kotlin ViewPager Output

Now, Let’s check how to use different attributes of ViewPager to customize it dynamically –

Set Id of ViewPager

Follow steps below to set id of ViewPager programmatically –

• Create ids.xml file in res/values folder. Then, add below code into it –

  <?xml version="1.0" encoding="utf-8"?>
  <resources>
      <item type="id" name="viewPager_ID" />
  </resources>
  

• Now, we can set id of ViewPager dynamically, in MainActivity.kt file, as –

  viewPager.id = R.id.viewPager_ID  // ViewPager
  

  Here, we have set id of ViewPager using property access syntax – viewPager.id

Learn to Set ID of ViewPager Using XML Attribute

Set Width and Height of ViewPager

We use layoutParams to set width and height of any View programmatically. In this article, we have added ViewPager in LinearLayout. So, we will define LayoutParams as below –

viewPager.layoutParams = LinearLayout.LayoutParams(
	ViewGroup.LayoutParams.WRAP_CONTENT,
	ViewGroup.LayoutParams.WRAP_CONTENT
)

Here, we have set width and height as WRAP_CONTENT. Some of possible values for width and height are –

• WRAP_CONTENT: Sets value of width or height depending on text inside it.
• MATCH_PARENT: Sets value of width of height depending on width or height of parent layout . i.e. width or height of ViewPager will be same as width or height of parent layout.
• Fixed Value: Sets width or height as per value provided.

Learn to Set Width or Height of ViewPager Using XML Attribute

Set Padding of ViewPager

Follow steps below to set padding of ViewPager Dynamically –

• If there is no dimens.xml file, create dimens.xml file in res/values folder. Then, add below code in it –

  <?xml version="1.0" encoding="utf-8"?>
  <resources>
      <dimen name="text_padding">16dp</dimen>
  </resources>
  

• Now, we can set padding of ViewPager dynamically, in MainActivity.kt file, as –

  val padding = resources.getDimension(R.dimen.text_padding).toInt()
  viewPager.setPadding(padding, padding, padding, padding)
  

  Here, we have accessed dimension defined in dimens.xml using getDimension() method. Then, set padding of ViewPager using setPadding() method.

Learn to Set Padding of ViewPager Using XML Attribute

Set Margin of ViewPager

Follow steps below to set margin of ViewPager Dynamically –

• If there is no dimens.xml file, create dimens.xml file in res/values folder. Then, add below code in it –

  <?xml version="1.0" encoding="utf-8"?>
  <resources>
      <dimen name="text_margin">16dp</dimen>
  </resources>
  

• Now, we can set margin of ViewPager dynamically, in MainActivity.kt file, as –

  val margin = resources.getDimension(R.dimen.text_margin).toInt()
  val layoutParams = LinearLayout.LayoutParams(
  	ViewGroup.LayoutParams.WRAP_CONTENT,
  	ViewGroup.LayoutParams.WRAP_CONTENT
  )
  layoutParams.setMargins(margin, margin, margin, margin)
  viewPager.layoutParams = layoutParams
  

  Here, we have accessed dimension defined in dimens.xml using getDimension() method. Then, we have defined layoutParams, set margin to layoutParams. After that, set layoutParams to ViewPager.

Learn to Set Margin of ViewPager Using XML Attribute

Set Background of ViewPager

Follow steps below to set background of ViewPager programmatically –

• If there is no colors.xml file, create colors.xml file in res/values folder. Then, add below code in it –

  <?xml version="1.0" encoding="utf-8"?>
  <resources>
      <color name="purple_200">#FFBB86FC</color>
  </resources>
  

• Now, we can set background of ViewPager dynamically, in MainActivity.kt file, as –

  val color = ContextCompat.getColor(this, R.color.purple_200)
  viewPager.setBackgroundColor(color)
  

  Here, we used setBackgroundColor() method to set background color in viewPager.

Learn to Set Background of ViewPager Using XML Attribute

Set Visibility of ViewPager

We can set visibility of ViewPager programmatically as –

viewPager.visibility = View.VISIBLE

Here, we have set visibility of ViewPager using viewPager.visibility attribute. Visibility can be of three types – gone, visible and invisible.
Learn to Set Visibility of ViewPager Using XML Attribute

That’s end of tutorial on ViewPager Programmatically in Kotlin With Example.