CountDownTimer
MainActivity import androidx.appcompat.app.AppCompatActivityimport android.os.Bundleimport android.os.CountDownTimerimport com.qrvvacuna_desarrollo_qrv.countdowntimer.databinding.ActivityMainBindingclass MainActivity : AppCompatActivity() { private lateinit var binding: ActivityMainBinding private var timer: CountDownTimer? = null override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) binding = ActivityMainBinding.inflate(layoutInflater) setContentView(binding.root) binding.apply { bStart.setOnClickListener { startCountDownTimer(20000) } } } private fun startCountDownTimer(timeMillis: Long){ timer?.cancel() timer = object : CountDownTimer(timeMillis, 1){ override fun onTick(timeM: Long) { binding.tvTimer.text = timeM.toString() } override fun onFinish() { binding.tvTimer.text = “Finish” } }.start() }} activity_main.xml… Подробнее »CountDownTimer