SimpleTimer for make repeatable tasks or not, in Android without break or stops MainThread

SimpleTimer.kt

import java.util.Timer
import java.util.TimerTask
import kotlin.concurrent.timerTask

private const val DEFAULT_EXECUTION_RATE = 6000L

class SimpleTimer {

    var executionRate = DEFAULT_EXECUTION_RATE
    private var mTrigger: (() -> Unit)? = null
    private var timer: Timer? = null
    private var uiTask: TimerTask? = null

    fun start(isRepeated: Boolean = true, trigger: (() -> Unit)? = mTrigger) {
        if (trigger == null) return
        if (timer != null) stop()
        mTrigger = trigger
        timer = Timer()
        uiTask = timerTask {
            mTrigger?.invoke()
        }
        if (isRepeated) startRepeatedTask() else startUniqueTask()
    }

    private fun startRepeatedTask() {
        timer?.scheduleAtFixedRate(
            uiTask, executionRate * 2,
            executionRate
        )
    }

    private fun startUniqueTask() {
        timer?.schedule(uiTask, executionRate)
    }

    fun stop(forNow: Boolean = true) {
        uiTask?.cancel()
        timer?.purge()
        timer?.cancel()
        timer = null
        if(forNow.not()) mTrigger = null
    }

    fun isRunning(): Boolean = timer != null && uiTask != null
}