How to find the serial number of an Android device using Kotlin?

This example demonstrates how to find the serial number of an Android device 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: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:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/button"
      android:layout_centerInParent="true"
      android:layout_marginTop="16sp" />
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:onClick="showDeviceInfo"
      android:text="Get Serial Number" />
</RelativeLayout>

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

import android.Manifest
import android.app.AlertDialog
import android.content.Context
import android.content.pm.PackageManager
import android.os.Build
import android.os.Bundle
import android.telephony.TelephonyManager
import android.view.View
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.content.ContextCompat
class MainActivity : AppCompatActivity() {
   private val requestState = 100
   private var checkedPermission = PackageManager.PERMISSION_DENIED
   lateinit var manager: TelephonyManager
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      checkedPermission = ContextCompat.checkSelfPermission(this,
      Manifest.permission.READ_PHONE_STATE);
      if (Build.VERSION.SDK_INT >= 23 && checkedPermission !=
         PackageManager.PERMISSION_GRANTED) {
            requestPermission();
         } else
         checkedPermission = PackageManager.PERMISSION_GRANTED;
      }
      private fun requestPermission() {
         Toast.makeText(this, "Requesting permission", Toast.LENGTH_SHORT).show()
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            this.requestPermissions(arrayOf(Manifest.permission.READ_PHONE_STATE), requestState)
         }
      }
      fun showDeviceInfo(view: View) {
         manager = getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
         val dBuilder: AlertDialog.Builder = AlertDialog.Builder(this)
         val stringBuilder = StringBuilder()
         if (checkedPermission != PackageManager.PERMISSION_DENIED) {
            dBuilder.setTitle("Device Info")
            stringBuilder.append("""
            SERIAL : ${Build.SERIAL}
            """.trimIndent())
         } else {
            dBuilder.setTitle("Permission denied")
            stringBuilder.append("Can't access device info !")
         }
         dBuilder.setMessage(stringBuilder)
         dBuilder.show()
      }
      override fun onRequestPermissionsResult(requestCode: Int, vararg permissions: String?, grantResults: IntArray) {
         when (requestCode) {
            requestState -> if (grantResults.isNotEmpty() && grantResults[0] == PackageManager
            .PERMISSION_GRANTED) {
               checkedPermission = PackageManager.PERMISSION_GRANTED
            }
         }
      }
}

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="app.com.q11">
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
   <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