Is it possible to add a timer to the actionbar on android?

Question

I\'d like a simple mm:ss timer to be displayed on my actionbar, be able to pick the number of minutes to start counting down from and then call a method once it\'s

Answer 1

I've managed to do that by adding a TextView to the Action Bar as an Action View in the menu, then updating it at regular intervals using a CountDownTimer.
(Tested on an Android 3.0 emulator, an Android 4.3 emulator and a real device running Android 4.3).

Here's the XML for the menu item. Note that actionViewClass="android.widget.TextVew"
(showAsAction and actionViewClass don't have the android namespace because I'm using the support action bar).

In onCreateOptionsMenu, I find the MenuItem and call getActionView to assign it to private TextView, timerText. I also apply some padding here, so that it's not right at the edge of the screen.

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.break_timer, menu);

    MenuItem timerItem = menu.findItem(R.id.break_timer);
    timerText = (TextView) MenuItemCompat.getActionView(timerItem);

    timerText.setPadding(10, 0, 10, 0); //Or something like that...

    startTimer(30000, 1000); //One tick every second for 30 seconds
    return true;
}

I have a method called startTimer to start a CountDownTimer and update timerText in its onTick. I call startTimer from onCreateOptionsMenu to ensure that timerText is not accessed before it has been initialised. (Previously, I called startTimer from onCreate, but got a NullPointerException).

private void startTimer(long duration, long interval) {

    CountDownTimer timer = new CountDownTimer(duration, interval) {

        @Override
        public void onFinish() {
            //TODO Whatever's meant to happen when it finishes
        }

        @Override
        public void onTick(long millisecondsLeft) {
            int secondsLeft = (int) Math.round((millisecondsLeft / (double) 1000));
            timerText.setText(secondsToString(secondsLeft));
        }
    };

    timer.start();
}

I'm sure that anyone reading this will know a better way to convert an integer number of seconds to a timecode such as "00:00:00", but just in case I'll share the secondsToString method I used in onTick, above.

private String secondsToString(int improperSeconds) {

    //Seconds must be fewer than are in a day

    Time secConverter = new Time();

    secConverter.hour = 0;
    secConverter.minute = 0;
    secConverter.second = 0;

    secConverter.second = improperSeconds;
    secConverter.normalize(true);

    String hours = String.valueOf(secConverter.hour);
    String minutes = String.valueOf(secConverter.minute);
    String seconds = String.valueOf(secConverter.second);

    if (seconds.length() < 2) {
        seconds = "0" + seconds;
    }
    if (minutes.length() < 2) {
        minutes = "0" + minutes;
    }
    if (hours.length() < 2) {
        hours = "0" + hours;
    }

    String timeString = hours + ":" + minutes + ":" + seconds;
    return timeString;
}