Android/Kotlin: onKeyDown function is not working and fired

I wanted to calculate the screen touch time. I used the "onKeyUp" function when my finger was not on the screen and "isKeyPressed" returned false.I used the "onKeyDown" function when my finger was on the screen. I wanted to calculate these times but onKeyDown function is not fired (checked on debub) and because of that startTime's value come "0".

Can you help me?

class MainActivity : AppCompatActivity(),SensorEventListener {
        
            private lateinit var sensorManager: SensorManager
            private var sensorGyroscope: Sensor? = null
            private var sensorAccelerometer: Sensor? = null
            private var sensorPressure: Sensor? = null
        
            private var startTime: Long = 0
            private var endTime: Long = 0
        
            var isKeyPressed : Boolean = false
        
         override fun onKeyUp(keyCode: Int, event: KeyEvent): Boolean {
                isKeyPressed = false
        
                endTime = System.currentTimeMillis()
        
                val result : Long = endTime - startTime
        
                return true
            }
        
            override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
                isKeyPressed = true
        
                startTime = System.currentTimeMillis()
        
                return true
            }
    }