How to create animation using XML file in an Android App using Kotlin?

This example demonstrates how to create animation using XML files 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="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:padding="4dp"
   tools:context=".MainActivity">
<TextView
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerHorizontal="true"
   android:layout_marginTop="50dp"
   android:text="Tutorials Point"
   android:textAlignment="center"
   android:textColor="@android:color/holo_green_dark"
   android:textSize="32sp"
   android:textStyle="bold" />
<TextView
   android:textColor="@android:color/holo_purple"
   android:id="@+id/textView"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerInParent="true"
   android:text="Have a Wonderful day!"
   android:textSize="24sp"
   android:textStyle="bold" />
<Button
   android:layout_above="@id/buttonBlink"
   android:id="@+id/buttonZoom"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:text="Zoom" />
<Button
   android:id="@+id/buttonBlink"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:layout_alignParentBottom="true"
   android:text="Blink" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.os.Bundle
import android.view.View
import android.view.animation.Animation
import android.view.animation.AnimationUtils
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity(), Animation.AnimationListener {
   private lateinit var textView: TextView
   private lateinit var buttonZoom: Button
   private lateinit var buttonBlink: Button
   private lateinit var zoom: Animation
   private lateinit var blink: Animation
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      textView = findViewById(R.id.textView)
      buttonZoom = findViewById(R.id.buttonZoom)
      buttonBlink = findViewById(R.id.buttonBlink)
      blink = AnimationUtils.loadAnimation(applicationContext, R.anim.blink)
      blink.setAnimationListener(this)
      zoom = AnimationUtils.loadAnimation(applicationContext, R.anim.zoom)
      zoom.setAnimationListener(this)
      buttonZoom.setOnClickListener {
         textView.visibility = View.VISIBLE
         textView.startAnimation(zoom)
      }
      buttonBlink.setOnClickListener {
         textView.visibility = View.VISIBLE
         textView.startAnimation(blink)
      }
   }
   override fun onAnimationStart(animation:Animation) {}
   override fun onAnimationEnd(animation1:Animation) {}
   override fun onAnimationRepeat(animation:Animation) {}
}

Step 4 − Create a android resource directory (anim) and add animation resource file in the directory and add the following code −

blink.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<alpha
   android:duration="600"
   android:fromAlpha="0.0"
   android:interpolator="@android:anim/accelerate_interpolator"
   android:repeatCount="infinite"
   android:repeatMode="reverse"
   android:toAlpha="1.0" />
</set>

zoom.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
   android:fillAfter="true">
   <scale
      android:duration="1000"
      android:fromXScale="1"
      android:fromYScale="1"
      android:pivotX="50%"
      android:pivotY="50%"
      android:toXScale="3"
      android:toYScale="3">
   </scale>
</set>

Step 5 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://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

Azhar

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Updated on: 21-Jul-2020

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