CallReceiver.kt

class CallReceiver : PhonecallReceiver() {
    override fun onIncomingCallStarted(ctx: Context, number: String?, start: Date) {
      
      }
      override fun onOutgoingCallStarted(ctx: Context, number: String?, start: Date) {
     
      }
      override fun onIncomingCallEnded(ctx: Context, number: String?, start: Date?, end: Date) {
        
      }
      override fun onOutgoingCallEnded(ctx: Context, number: String?, start: Date?, end: Date) {
        
      }
      override fun onMissedCall(ctx: Context, number: String?, start: Date?) {
        
      }
}

PhonecallReceiver.kt

abstract class PhonecallReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {

        if (intent.action == "android.intent.action.NEW_OUTGOING_CALL") {
            savedNumber = intent.extras!!.getString("android.intent.extra.PHONE_NUMBER")
        } else {
            val stateStr = try {
                intent.extras!!.getString(TelephonyManager.EXTRA_STATE)
            } catch (e: Exception) {
                TelephonyManager.CALL_STATE_IDLE
            }

            val number = try {
                intent.extras!!.getString(TelephonyManager.EXTRA_INCOMING_NUMBER)
            } catch (e: Exception) {
                ""
            }

            var state = 0
            if (stateStr == TelephonyManager.EXTRA_STATE_IDLE) {
                state = TelephonyManager.CALL_STATE_IDLE
            } else if (stateStr == TelephonyManager.EXTRA_STATE_OFFHOOK) {
                state = TelephonyManager.CALL_STATE_OFFHOOK
            } else if (stateStr == TelephonyManager.EXTRA_STATE_RINGING) {
                state = TelephonyManager.CALL_STATE_RINGING
            }

            if (intent.hasExtra(TelephonyManager.EXTRA_INCOMING_NUMBER) &&
                intent.extras!!.getString(TelephonyManager.EXTRA_INCOMING_NUMBER) != null
            )
                onCallStateChanged(context, state, number)
        }
    }

    abstract fun onIncomingCallStarted(ctx: Context, number: String?, start: Date)

    abstract fun onOutgoingCallStarted(ctx: Context, number: String?, start: Date)
    abstract fun onIncomingCallEnded(ctx: Context, number: String?, start: Date?, end: Date)
    abstract fun onOutgoingCallEnded(ctx: Context, number: String?, start: Date?, end: Date)
    abstract fun onMissedCall(ctx: Context, number: String?, start: Date?)

    open fun onCallStateChanged(context: Context, state: Int, number: String?) {
        if (lastState == state) {
            return
        }
        when (state) {
            TelephonyManager.CALL_STATE_RINGING -> {
                isIncoming = true
                callStartTime = Date()
                savedNumber = number
                onIncomingCallStarted(context, number, callStartTime!!)
            }
            TelephonyManager.CALL_STATE_OFFHOOK ->
                if (lastState != TelephonyManager.CALL_STATE_RINGING) {
                    isIncoming = false
                    callStartTime = Date()
                    onOutgoingCallStarted(context, savedNumber, callStartTime!!)
                }
            TelephonyManager.CALL_STATE_IDLE ->
                if (lastState == TelephonyManager.CALL_STATE_RINGING) {
                    onMissedCall(context, savedNumber, callStartTime)
                } else if (isIncoming) {
                    onIncomingCallEnded(context, savedNumber, callStartTime, Date())
                } else {
                    onOutgoingCallEnded(context, savedNumber, callStartTime, Date())
                }
        }
        lastState = state
    }

    companion object {
        private var lastState = TelephonyManager.CALL_STATE_IDLE
        private var callStartTime: Date? = null
        private var isIncoming: Boolean = false
        private var savedNumber: String? =
            null
    }

}