How to rotate an image in imageview by an angle on Android using Kotlin?

This example demonstrates how to rotate an image in imageview by an angle on Android 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.

<?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="2dp"    tools:context=".MainActivity">    <ImageView       android:id="@+id/imageView"       android:layout_width="match_parent"       android:layout_height="600dp"       android:src="@drawable/image" />    <Button       android:layout_above="@+id/imageView"       android:id="@+id/btnRotate"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignParentBottom="true"       android:layout_centerInParent="true"       android:text="Rotate View"       android:textStyle="bold" /> </RelativeLayout>

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

import android.os.Bundle import android.widget.Button import android.widget.ImageView import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() {    lateinit var imageView: ImageView    lateinit var btnRotate: Button    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"       imageView = findViewById(R.id.imageView)       btnRotate = findViewById(R.id.btnRotate)       btnRotate.setOnClickListener { imageView.rotation = 90f }    } }

Step 4 − 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