MainActivity.kt

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    private var current = 0L

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        binding.customViewOne.setPeriod(PERIOD)
        binding.customViewTwo.setPeriod(PERIOD)

        // Never use GlobalScope for real projects !!!
        GlobalScope.launch {
            while (current < PERIOD * REPEAT) {
                current += INTERVAL
                binding.customViewOne.setCurrent(current)
                binding.customViewTwo.setCurrent(current)
                delay(INTERVAL)
            }
        }
    }

    private companion object {

        private const val INTERVAL = 100L
        private const val PERIOD = 1000L * 30 // 30 sec
        private const val REPEAT = 10 // 10 times
    }
}