Android Kotlin CountDown Timer for time add

问题

in the timer I use how to add a time when a button is pressed? for example, I want millisUntilFinished to increase by 5 seconds when I press a button. I tried with the global variable but it didn't.

 object :CountDownTimer(10000,1000){
            override fun onFinish() {

                timeText.text = "Left : 0"
                handler.removeCallbacks(runnable)
                for (image in imageArray){
                    image.visibility = View.INVISIBLE
                }
                for (add in timeAdd){
                    add.visibility = View.INVISIBLE
                }
                button.visibility = View.VISIBLE
            }

            override fun onTick(millisUntilFinished: Long) {
                 timeText.text = "Left : "+millisUntilFinished/1000
            }

        }.start()

回答1:

Here is a count down timer we use

fun message(msg:String){
    object : CountDownTimer(4000, 1000) {
        override fun onTick(millisUntilFinished: Long) {
            tvMsg.visibility = View.VISIBLE
            tvMsg.text = msg
        }
        override fun onFinish() {
            tvMsg.visibility = View.INVISIBLE
            tvMsg.text = ""
        }
    }.start()
}

And our use of a plain timer

    if (result) {
        etItemData.setText("")
        message("Record Removed")
        Timer().schedule(1000){
            thisACTIVITY()
        }

Kotlin complains about this not sure why

回答2:

As @TheWanderer answered you can not update the millisUntilFinished as there is no such method available in CountDownTimer class.

To update the Timer you need to stop the current timer and start the new timer with updated millisInFuture value. Here is the sample code which will help you to achieve what you want.

    var timer: Timer?=null

    //Call this method to start timer on activity start
    private fun startTimer(){
        timer = Timer(10000);
        timer?.start()
    }

    //Call this method to update the timer
    private fun updateTimer(){
        if(timer!=null) {
            val miliis = timer?.millisUntilFinished + TimeUnit.SECONDS.toMillis(5)
            //Here you need to maintain single instance for previous
            timer?.cancel()
            timer = Timer(miliis);
            timer?.start()
        }else{
            startTimer()
        }
    }

    inner class Timer(miliis:Long) : CountDownTimer(miliis,1000){
        var millisUntilFinished:Long = 0
        override fun onFinish() {
            timeText.text = "Left : 0"
            handler.removeCallbacks(runnable)
            for (image in imageArray){
                image.visibility = View.INVISIBLE
            }
            for (add in timeAdd){
                add.visibility = View.INVISIBLE
            }
            button.visibility = View.VISIBLE
        }

        override fun onTick(millisUntilFinished: Long) {
            this.millisUntilFinished = millisUntilFinished
            timeText.text = "Left : "+millisUntilFinished/1000
        }
    }

回答3:

You can't change the remaining time on an already-created CountDownTimer.

Looking at the source, both millisInFuture and countDownInterval are assigned to final variables; you can't change them.

Now, the mStopTimeInFuture variable, the one the timer actually uses to stop, isn't final, and can be changed. But it's a private variable, meaning you'd need to use reflection, and it might not work properly.

If you want a mutable CountDownTimer, you'll need to roll your own (easiest way would probably be to copy the CountDownTimer source and make the mStopTimeInFuture variable public and add milliseconds to it when needed).

来源：https://stackoverflow.com/questions/52647719/android-kotlin-countdown-timer-for-time-add

标签

android

kotlin

countdowntimer