How do I check if system is 12 or 24 hour?

Shouldn't it be

if (!DateFormat.is24HourFormat(this))

You want to assign am/pm only when it is not set to 24 hour format, right?

Here is a more compact version:

if (!DateFormat.is24HourFormat(this)) {    mHour = mCalendar.get(Calendar.HOUR_OF_DAY);    int hourOfDay = mHour;    if (hourOfDay >= 12) {        views.setTextViewText(R.id.AMPM, "pm");    } else {        views.setTextViewText(R.id.AMPM, "am");    }} else {    views.setTextViewText(R.id.AMPM, "");}

Better solution and whole code sample:

Calendar calendar = Calendar.getInstance();calendar.setTimeInMillis(System.currentTimeMillis());// below, the "hour" and "min" are variables,to which you want to set //calendar.For example you can take this values from time pickercalendar.set(Calendar.HOUR_OF_DAY, hour);calendar.set(Calendar.MINUTE, min);            is24HourFormat = android.text.format.DateFormat.is24HourFormat(context);if (is24HourFormat) {    // if system uses 24hourformat dateFormat will format the calender time according to 24hourformat. "HH" means 24hourformat    CharSequence setTime = dateFormat.format("HH:mm", calendar);} else {    // if system doesnt use 24hourformat dateFormat will format the calender time according to 12hourformat. "hh" means 12hourformat and "a" will show am/pm marker    CharSequence setTime = dateFormat.format("hh:mm a", calendar);}

To always display AM/PM in 12-hour format and not something like vorm/nachm in german, use Locale.US for the date format:

/** * Returns the time in a localized format. The 12-hours format is always displayed with * AM/PM (and not for example vorm/nachm in german). * * @param context the context * @return Localized time (15:24 or 3:24 PM). */public static String getTime(Context context, long time) {    if (android.text.format.DateFormat.is24HourFormat(context)) {        return new SimpleDateFormat("HH:mm", Locale.US).format(new Date(time));    } else {        return new SimpleDateFormat("hh:mm a", Locale.US).format(new Date(time));    }}