How can I generate random numbers in a given range in Android using Kotlin?

This example demonstrates how to generate random numbers in a given range 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="https://schemas.android.com/apk/res/android"
   xmlns:tools="https://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="50dp"
      android:text="Tutorials Point"
      android:textAlignment="center"
      android:textColor="@android:color/holo_green_dark"
      android:textSize="32sp"
      android:textStyle="bold" />
   <Button
      android:id="@+id/btn_generate"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/editTextMax"
      android:layout_centerInParent="true"
      android:layout_marginTop="5dp"
      android:text="GENERATE" />
   <EditText
      android:id="@+id/editTextMin"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/text"
      android:layout_centerInParent="true"
      android:layout_marginTop="50dp"
      android:ems="10"
      android:hint="Minimum"
      android:inputType="number" />
   <EditText
      android:id="@+id/editTextMax"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/editTextMin"
      android:layout_centerHorizontal="true"
      android:ems="10"
      android:hint="Maximum"
      android:inputType="number" />
   <TextView
      android:id="@+id/textViewResult"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/btn_generate"
      android:layout_centerInParent="true"
      android:layout_marginTop="10dp"
      android:hint="Output"
      android:text=""
      android:textColor="@android:color/black"
      android:textSize="24sp"
      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.EditText
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import java.util.*
class MainActivity : AppCompatActivity() {
   lateinit var editTextMin: EditText
   lateinit var editTextMax: EditText
   lateinit var button: Button
   lateinit var textView: TextView
   private var min = 0
   private var max: Int = 0
   private var output: Int = 0
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      val random = Random()
      editTextMin = findViewById(R.id.editTextMin)
      editTextMax = findViewById(R.id.editTextMax)
      button = findViewById(R.id.btn_generate)
      textView = findViewById(R.id.textViewResult)
      button.setOnClickListener {
         val tempMin: String = editTextMin.text.toString()
         val tempMax: String = editTextMax.text.toString()
         if (tempMin != "" && tempMax != "") {
            min = tempMin.toInt()
            max = tempMax.toInt()
            if (max > min) {
               output = random.nextInt(max − min + 1) + min textView.text = "" + output
            }
         }
      }
   }
}

Step 4 − Add the following code to androidManifest.xml

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