Question

have a clock I want to display in a TextView.

I would have thought there was a few nice functions to do this, but I couldn’t find anything.
I ended up implementing my own way that uses a Handler. What I’m asking though, is there a better (more efficient) way to display a real time updating clock?

private Runnable mUpdateClockTask = new Runnable() {
   public void run() {
       setTime();
       mClockHandler.postDelayed(this, 1000);
   }
};

That’s my handler, which runs every second, and then my set time and date function is below

TextView mClockView;

public void setTime() {
    Calendar cal = Calendar.getInstance();
    int minutes = cal.get(Calendar.MINUTE);

    if (DateFormat.is24HourFormat(this)) {
        int hours = cal.get(Calendar.HOUR_OF_DAY);
        mClockView.setText((hours < 10 ? "0" + hours : hours) + ":" + (minutes < 10 ? "0" + minutes : minutes));
    }
    else {
        int hours = cal.get(Calendar.HOUR);
        mClockView.setText(hours + ":" + (minutes < 10 ? "0" + minutes : minutes) + " " + new DateFormatSymbols().getAmPmStrings()[cal.get(Calendar.AM_PM)]);
    }
}

Cheers

Answer 1

Remember: premature optimization is the root of all evil. So only optimize when you are sure (=have measured it) that your implementation is slow/inefficient.

That said, a more efficient method would probably be to record start time via System.currentTimeMillis() and then periodically check it and calculate difference in minutes.