MainActivity.kt
package com.cscorner.myapplication4

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.cscorner.myapplication4.databinding.ActivityMainBinding
import kotlin.math.ceil

class MainActivity : AppCompatActivity() {
    lateinit var binding: ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.button.setOnClickListener() {
            calculateTip()
        }
    }
    fun calculateTip()
    {
        val cost =(binding.cost.text.toString()).toDouble()
        val selected =binding.RG.checkedRadioButtonId
        val tipPercent=when(selected)
        {
            R.id.radioButton ->15
            R.id.radioButton2 ->18
            else -> 20
        }
        var tip=tipPercent*cost
        if(binding.switch2.isChecked)
        {
            tip= ceil(tip)
        }
        binding.textView7.text=tip.toString()
    }
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/cost"
        android:layout_width="241dp"
        android:layout_height="55dp"
        android:ems="10"
        android:inputType="text"
        android:text="Cost"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.119" />

    <RadioGroup
        android:id="@+id/RG"
        android:layout_width="253dp"
        android:layout_height="154dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.5"
        tools:ignore="UnknownId">

        <RadioButton
            android:id="@+id/radioButton"
            android:layout_width="match_parent"
            android:layout_height="48dp"
            android:text="Excelent" />

        <RadioButton
            android:id="@+id/radioButton2"
            android:layout_width="match_parent"
            android:layout_height="48dp"
            android:text="Very Good" />

        <RadioButton
            android:id="@+id/radioButton3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:minHeight="48dp"
            android:text="Bad" />

    </RadioGroup>

    <Switch
        android:id="@+id/switch2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:minHeight="48dp"
        android:text="Switch"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.672"
        tools:ignore="UnknownId,UseSwitchCompatOrMaterialXml" />

    <Button
        android:id="@+id/button"
        android:layout_width="166dp"
        android:layout_height="48dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.79"
        tools:ignore="UnknownId" />

    <TextView
        android:id="@+id/textView7"
        android:layout_width="182dp"
        android:layout_height="30dp"
        android:text="TextView"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.91"
        tools:ignore="UnknownId" />

</androidx.constraintlayout.widget.ConstraintLayout>
Build katle
plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.jetbrains.kotlin.android)
}

android {
    namespace = "com.cscorner.myapplication4"
    compileSdk = 35

    defaultConfig {
        applicationId = "com.cscorner.myapplication4"
        minSdk = 24
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"

        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            isMinifyEnabled = false
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
    buildFeatures{
        viewBinding= true
    }
}

dependencies {



    implementation(libs.material)
    implementation(libs.androidx.activity)


    androidTestImplementation(libs.androidx.junit)

    implementation ("androidx.core:core-ktx:1.7.0")
    implementation ("androidx.appcompat:appcompat:1.6.1")
    implementation ("com.google.android.material:material:1.9.0")
    implementation ("androidx.constraintlayout:constraintlayout:2.1.4")
    testImplementation ("junit:junit:4.13.2")
    androidTestImplementation ("androidx.test.ext:junit:1.1.5")
    androidTestImplementation ("androidx.test.espresso:espresso-core:3.5.1")
}