class MainActivity : AppCompatActivity() {
     private lateinit var otpTextView : OTPTextView

     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_sample1)

         val errorButton = findViewById<Button>(R.id.button)
         val successButton = findViewById<Button>(R.id.button2)
         otpTextView = findViewById(R.id.otp_view) as OTPTextView
         otpTextView.requestFocusOTP()
         otpTextView.otpListener = object : OTPListener {
             override fun onInteractionListener() {

             }

             override fun onOTPComplete(otp: String) {
                 Toast.makeText(this@MainActivity, "The OTP is $otp", Toast.LENGTH_SHORT).show()
             }
         }
         errorButton.setOnClickListener { otpTextView.showError() }
         successButton.setOnClickListener { otpTextView.showSuccess() }

         additionalMethods()
     }

     fun additionalMethods() {
         otpTextView.getOtpListener();  // retrieves the current OTPListener (null if nothing is set)
         otpTextView.requestFocusOTP();	//sets the focus to OTP box (does not open the keyboard)
         otpTextView.setOTP(otpString);	// sets the entered otpString in the Otp box (for case when otp is retrieved from SMS)
         otpTextView.getOTP();	// retrieves the OTP entered by user (works for partial otp input too)
         otpTextView.showSuccess();	// shows the success state to the user (can be set a bar color or drawable)
         otpTextView.showError();	// shows the success state to the user (can be set a bar color or drawable)
         otpTextView.resetState();	// brings the views back to default state (the state it was at input)
     }
 }