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Android Joda DateTime one hour off

I have a TimePickerDialog which lets the user pick a time. The TimePickerDialog has a onTimeSet method that gets called when the user finished picking the time.
I pass the arguments to a second method, setTime(int hour, int minute) which saves the values and displays a formatted time.
Here is a code snippet of the method:
java.text.DateFormat dateFormatter =
java.text.DateFormat.getTimeInstance(java.text.DateFormat.SHORT, Locale.getDefault());
DateTime dt = new DateTime();
dt = dt.hourOfDay().setCopy(hour);
dt = dt.minuteOfHour().setCopy(minute);
String text = dateFormatter.format(dt.toDate());
The Problem is that (sometimes, not always) the hour value is off by one or maybe even two hours. I think the cause of the problem has something to do with timezones, but I do not know what the exact cause is. I also think that the problem is caused by the Joda DateTime object, since I did not have any issues before I implemented Joda time AND because it also gets saved with one hour off.
Any ideas what happens / how to fix it?

For this answer, I'm using joda-time 2.7 (although it might work with previous versions).
I'm also assuming that your program only cares about hour and minute (I'm not an Android expert, but I saw docs from TimePickerDialog and it seems to be the case).
So, if you're manipulating only hour and minute, you don't need to use DateTime class (actually you shouldn't in this case).
That's because a DateTime object is "aware" of all date fields, including day, month, year and timezone. So, when you create a new DateTime(), it creates a new object with current date and time in your default timezone. And if the current date in default timezone is in summer time (aka daylight saving time), you can have these hour shifts.
(And I believe that Android takes the default timezone from the device's system, so it can vary according to the device running the code - at least that's how it works in computers, so it shouldn't be different for devices).
As you don't need to know day/month/year and timezone, you can use LocalTime class (org.joda.time.LocalTime) which is a class with only hour and minute fields (and seconds, if you want; if you don't care about seconds, they'll be set to zero). And the best part is: this class doesn't care about timezones, so 10:00 AM will always be 10:00 AM.
You also don't need to use java.text.DateFormat, as joda-time has its own formatters. So the code will be like this:
public void setTime(int hour, int minute) {
// shortTime() is equivalent to DateFormat.SHORT
DateTimeFormatter fmt = DateTimeFormat.shortTime().withLocale(Locale.getDefault());
LocalTime time = new LocalTime(hour, minute);
String text = fmt.print(time);
System.out.println(text);
}
Doing some tests (assuming default locale is en_US):
setTime(9, 30); // prints 9:30 AM
setTime(10, 0); // prints 10:00 AM
PS: the output may vary according to your default Locale (which I also believe it comes from the device's system). If you want a fixed format (independent from locales), you can use DateTimeFormat.forPattern("h:mm a"), which also results in the output above (and when you use formatters this way, the default locale doesn't change the output).

Getting Current Time for Booking

I know this is very simple question but I am not able to do it.
I have a code that gets current time but this time is not accurate.
booking.CreateDateTime = DateTime.Now.ToUniversalTime();
When I am booking at 12:00 then in database stores 1:00 that means 1 hour difference.
How can I get accurate time?

Use System.currentTimeMillis() to get the current GMT time in mili seconds since epoch.
Then you can use this value to create a new Date or Calendar object and localize it wherever the user is.

I'm not familiar with what you have there, but ToUniversalTime suggests to me that this is adjusting your time to some fixed time zone (probably GMT)
Use a Date to get the time right now, and then a Calendar to do any time zone changes on it that you want.
Example, assuming CreateDateTime is actually a string of what you said it was:
Date date = new Date();
Calendar calendar = new GregorianCalendar();
calendar.setTime(date);
booking.CreateDateTime = calendar.get(Calendar.HOUR_OF_DAY) + ":" + calendar.get(Calendar.MINUTE));

calendar.set(Calendar.HOUR_OF_DAY, alarmHour); is not working. What am I doing wrong?

I am setting an alarm for which I take the Hour and Minutes from a TextView and the AM/PM through a Spinner. Here is how I initialize the Calendar object:
Calendar calen = Calendar.getInstance();
calen.set(Calendar.HOUR_OF_DAY, alarmHour); //alarmHour from TextView
calen.set(Calendar.MINUTE, alarmMinute); //alarmMinute from TextView
calen.set(Calendar.SECOND, 0);
calen.set(Calendar.MILLISECOND, 0);
if(amorpm.equals("PM") //amorpm from Spinner
{
calen.set(Calendar.AM_PM, Calendar.PM);
}
else
{
calen.set(Calendar.AM_PM, Calendar.AM);
}
The problem is the Hour value of this Calendar object is sometimes correct i.e. the value which the user enters in the TextView (and it is always 1 to 12). But sometimes, the value is equal to the current Hour. For example, if the current time is 11:30 pm, and I set the alarm for 9:30 am, then the Hour field has the value 11. One strange thing is that when I change the name of the Calendar object to something else, say cal, it works. But wont work later. What could be wrong ?
Thanks for your help!

I think the solution is to call calen.set(Calendar.HOUR, alarmHour); instead of calen.set(Calendar.HOUR_OF_DAY, alarmHour);
The trouble is you are setting the Calendar.HOUR_OF_DAY field and then setting the AM/PM field. "Hour of day" is hour in the full 24-hour day, and therefore using it in conjuction with AM/PM doesn't make sense. According to the Java documentation (http://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html), when setting the time of day, if conflicting information is presented, then the most recently set information will be used according to the following combinations:
HOUR_OF_DAY
AM_PM + HOUR
Because you are setting the AM/PM field after the hour, the hour is taken from the Calendar.HOUR field, which is of course initialised to the current hour when you create the instance.
The naming of the variable is, of course, a red herring. That can't possibly affect it.

Android: getting the time

i am currently using the following line to achieve the time: System.currentTimeInMilis.
I have noticed it doesn't consider time zones,or does it not match the android phone it self by the time, while on the emulator it does match.s
so is there another type of way to get the android clock it self? so when the user adjusts he's phones built in clock, it affects it too?
float getTime()
{
Calendar cal = new GregorianCalendar();
cal.setTimeInMillis(System.currentTimeMillis());
cal.setTimeZone(TimeZone.getDefault());
return cal.getTimeInMillis();
}

Read the documentation of currentTimeMillis. It has a time zone, which happens to be UTC (which is the default for Unix time stamps).
If you want to convert it to a different time zone you can make use of the Java Calendar and TimeZone classes:
Calendar cal = new GregorianCalendar();
cal.setTimeInMillis(System.currentTimeMillis());
cal.setTimeZone(TimeZone.getDefault());
Alternatively you can just create a new GregorianCalendar instance. By default its TimeZone will match the local one (as set on the device) and the time will be set to "now".
There are also other ways for retrieving the current time according the current time zone and locale as string. Take a look at DateUtils.
EDIT Explaining the usage of Calendar
Read the documentation for Calendar.getTimeMillis(). That method returns the Unix time stamp again which happens to have the time zone UTC.
You have to use the Calendar.get() method instead for getting the correct values. See following example for getting the current hour in the correct time zone via your calendar object:
int hour = cal.get(Calendar.HOUR_OF_HAY);
Read the documentation of Calendar. There are plenty of fields like HOUR_OF_DAY which help you getting values like the year, month, minute, seconds etc.

Problem with Calendar.get(Calendar.HOUR)

I am trying to display in a TextView when my application last updated (e.g., "Last updated at 12:13). I am trying to use a Calendar instance and I thought I understood it correctly but I seem to be having trouble. I know to get an instance I use the method Calendar.getInstance(). And then to get the hour and minute I was using Calendar.get(Calendar.HOUR) and Calendar.get(Calendar.MINUTE). My minute field returns correctly but Calendar.HOUR is returning the hour on a 24 hour clock and I want a 12 hour clock. I thought HOUR_OF_DAY was 24 hour clock. Where am I going wrong?
Here is the code I'm using:
Calendar rightNow = Calendar.getInstance();
mTv.setText("Refreshed! Last updated " +
rightNow.get(Calendar.HOUR) + ":" +
rightNow.get(Calendar.MINUTE) + ".");
mTv is my TextView that I'm updating. Thanks for any help.
Also, it would be ideal if I could say "Last updated 5 minutes ago." instead of "Last updated at 12:13pm". But I'm not sure the best way to have this update each minute without draining resources or the battery...?

I'd recommend using SimpleDateFormat in combination with the Date class for formatting the time:
Date now = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("K:mm a");
String formattedTime = sdf.format(now);
Short explanation how it works:
You create a SimpleDateFormat object and pass a String to it's construtor which tells it how to format every time/date object that gets passed to the format() function of it.
There are plenty of constants/letters which represent a special time object (e.g. seconds, an AM/PM marker, .. see the class documentation for the full list).
"K:mm a" means a "11:42 AM" format - one or two digits for the hour (depending on its value) in a 12 hour format, always two digits for minutes (mm) and either AM or PM (a), depending on the time.
After you did that, just pass a Date object to the format() function, and you'll get a formatted string. Note that a Date just holds one single point in time, if you create it from the constructor with no arguments ("= new Date()") it uses the current time. If you need another time, you can pass a long argument with the millis, you may get that from Calendar.getTimeInMillis().
As of implementing the "updated XY minutes ago function" - yes you'd have to update this every minute and you have to calculate the difference between the update and the current time. I'd say it's not worth it from a battery and extra work perspective.
If your app uses standard short update cycles (e.g. every hour or somthing along those lines) and is not fullscreen, the user has a visible clock on top/bottom of his screen. If he really wants to check how long it was since the update, he can take a short look and compare (mostly just minutes or hours/minutes). And IMHO thats no inconvinience for a user, at least it would not for me. I'd just compare without thinking about that. But I tend to kill apps which waste my battery for no useful reason.
Also note that not everybody uses a 12-hour format. To get a localized time format depending on users settings/country use DateFormat.getTimeInstance(). This returns a DateFormat, but this works like the SimpleDateFormat, just pass a time to format().

Use Calendar.HOUR_OF_DAY for 24h clock
Calendar rightNow = Calendar.getInstance();
mTv.setText("Refreshed! Last updated " +
rightNow.get(Calendar.HOUR_OF_DAY) + ":" +
rightNow.get(Calendar.MINUTE) + ".");

You can update editText in each minute using a thread like following
Thread t = new Thread(){
public void run() {
Calendar oldTime = Calendar.getInstance();
oldMinute = oldTime .get(Calendar.MINUTE);
while(true) {
Calendar rightNow= Calendar.getInstance();
newMinute = rightNow.get(Calendar.MINUTE);
if(newMinute != oldMinute) {
oldMinute = newMinute;
mTv.setText("Refreshed! Last updated " +
rightNow.get(Calendar.HOUR) + ":" +
rightNow.get(Calendar.MINUTE) + ".");
}
}
}
t.start();

Well, Calendar.get(Calendar.HOUR) should be returning 12-hour time, but if you wanted to produce your slightly nicer text, you can use the TimeUnit class for parsing simplicity.
long millis = Calendar.getInstance().getTimeInMillis();
String.format("Last updated %d min, %d sec ago.",
TimeUnit.MILLISECONDS.toMinutes(millis),
TimeUnit.MILLISECONDS.toSeconds(millis) -
TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))
);