Hello Readers! In this post, we are going to learn about how to use android viewStub programmatically in kotlin in the application. We will also learn how to add viewStub to linearLayout programmatically in android application.

Output

Tutorialwing Kotlin Dynamic ViewStub Output

Getting Started

At first, we will create android project. Then, we will create and use viewStub programmatically in kotlin file.

1. Creating New Project in Kotlin

Follow the steps below to create new project. Please ignore the steps if you have already created a new project.

Now, we will modify xml and kotlin file to use viewStub dynamically.

2. Modify Values Folder

Open res/values/strings.xml file. Then, add below code into it.

<resources>
	<string name="app_name">DynamicViewStub</string>
	<string name="hide">HIDE</string>
	<string name="show">SHOW</string>
	<string name="sub_view">This view is inflated by ViewStub by calling either inflate() or setVisibility(true) method</string>
</resources>

3. Create Views That replaces ViewStub On inflate() Call

Now, we will create an xml file, named sub_item.xml, that are inflated when viewStub.inflate() method is called. Then, add below code into it.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:background="@android:color/holo_blue_light"
	android:gravity="center"
	android:padding="10dp">

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:gravity="center"
		android:text="@string/sub_view"
		android:textColor="@android:color/black"
		android:textSize="18sp"/>

</LinearLayout>

4. Modify Layout Folder

Open res/layout/activity_main.xml file. Then, add below code into it.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
	android:id="@+id/rootContainer"
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:layout_margin="10dp"
	android:gravity="center_horizontal"
	android:orientation="vertical">

	<Button
		android:id="@+id/button"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="@string/hide"/>

</LinearLayout>

In activity_main.xml file, we have defined a linearLayout, with id rootContainer, that acts as container for the viewStub created programmatically in the application.

5. Create Android ViewStub Programmatically / Dynamically in Kotlin

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

package com.tutorialwing.dynamicviewstub

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.View
import android.view.ViewGroup
import android.view.ViewStub
import android.widget.Button
import android.widget.LinearLayout

class MainActivity : AppCompatActivity() {

    private var isViewInflated = true // Default state that represents viewStub has been replaced by sub view

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

        val viewStub = ViewStub(this)
        val layoutParams = LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)
        viewStub.layoutParams = layoutParams
        viewStub.layoutResource = R.layout.sub_item

        val linearLayout = findViewById<LinearLayout>(R.id.rootContainer)
        linearLayout?.addView(viewStub)

        viewStub.visibility = View.VISIBLE // or you can use viewStub.inflate()

        val button = findViewById<Button>(R.id.button)
        button?.setOnClickListener {
            isViewInflated = !isViewInflated
            viewStub.visibility = if (isViewInflated) View.VISIBLE else View.GONE
            button.text = if (isViewInflated) getString(R.string.hide) else getString(R.string.show)
        }
    }
}

We have created viewStub programmatically in kotlin file (i.e. in MainActivity.kt file). Then, we have set layout params etc. in it. Attribute layoutResource is used to specify layout resource that replaces viewStub on inflate() method call. After that, we have added viewStub in linearLayout having id rootContainer. Finally, we have set click listener on button to toggle visibility of inflated view by viewStub.

Since AndroidManifest.xml file is very important in any android application, we are also going to see the content inside this file.

AndroidManifest.xml file

Code inside src/main/AndroidManifest.xml file is –

<?xml version="1.0" encoding="utf-8"?>
<manifest package="com.tutorialwing.dynamicviewstub"
		  xmlns:android="http://schemas.android.com/apk/res/android">

	<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>

When we run the program, we will get output as shown above.

That’s end of our tutorial on Creating Android ViewStub Programmatically in Kotlin.