How to change the color of a CheckBox in Android using Kotlin?

This example demonstrates how to change the color of a CheckBox in 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"    tools:context=".MainActivity">    <TextView       android:id="@+id/text"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerHorizontal="true"       android:layout_marginTop="70dp"       android:background="#008080"       android:padding="5dp"       android:text="TutorialsPoint"       android:textColor="#fff"       android:textSize="24sp"       android:textStyle="bold" />    <TextView       android:id="@+id/textView"       android:layout_width="wrap_content"          android:layout_height="wrap_content"       android:layout_centerInParent="true"       android:text="Click the check box"       android:textColor="@android:color/holo_blue_dark"       android:textSize="16sp"       android:textStyle="bold" />    <CheckBox       android:id="@+id/checkbox"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_below="@id/textView"       android:layout_centerInParent="true"       android:text="Check box" />    <Button       android:id="@+id/button"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_below="@id/checkbox"       android:layout_centerInParent="true"       android:text="Change Color" /> </RelativeLayout>

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

import android.graphics.Color import android.os.Bundle import android.widget.Button import android.widget.CheckBox import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() {    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"       val checkBox: CheckBox = findViewById(R.id.checkbox)       val button: Button = findViewById(R.id.button)       button.setOnClickListener {          checkBox.setTextColor(Color.MAGENTA)          checkBox.setBackgroundColor(Color.parseColor("#cbff75"))       }    } }

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