CountDownTimer firing onTick at not excepted time point

Question

I have the following CountDownTimer:

countdown = new CountDownTimer(10000, 5000) {
        @Override
        public void onTick(long millisUntilFinished) {
            // Stuff here
        }

        @Override
        public void onFinish() {
            // Restart countdown
            countdown.start();
        }
    }.start();

As seen, there's a 5 seconds tick interval. But when this CountDown starts, the first interval occurs at 0 miliseconds.

Why my first tick is being fired at 0 miliseconds time, instead of 5000 miliseconds time?

Answer 1

All the documentation has to say about onTick() is "Callback fired on regular interval."

http://developer.android.com/reference/android/os/CountDownTimer.html#onTick(long)

Why are you assuming it shouldn't fire immediately?

If want to ignore the first callback to onTick() you could add a boolean flag like so:

countdown = new CountDownTimer(10000, 1000) {
        private boolean first = true;
        @Override
        public void onTick(long millisUntilFinished) {
            if (first) {
                first = false;
                return;
            }
            // Stuff here
        }

        @Override
        public void onFinish() {
            // Restart countdown
            first = true;
            countdown.start();
        }
    }.start();

After looking at your usage of CountDownTimer a bit more it seems like you could also use a Handler / Runnable combination.

Here's an example:

In your Activity you do:

private Handler timerHandler;
private Runnable timerRunnable;

// ...

@Override
public void onCreate() {
    super.onCreate();
    timerHandler = new Handler();
    timerRunnable = new Runnable() {
        @Override
        public void run() {
            // Stuff here
            timerHandler.postDelayed(timerRunnable, 5000);
        }
    };
    timerHandler.postDelayed(timerRunnable, 5000);
}