[Android] Date, Time, Calendar, Format

1. Classes
   
   • Date
   • Time
   • Format
     
     • DateFormat (this class is defined in the packages android.text.format & java.text, that in the pakcage android.text.format provids more interfaces)
       
     • SimpleDateFormat
     • DateFormatSymbols
     • xxx
       
   • Utils
     
     • DateUtils
     • TimeUtils
   • xxx
     
2. Get current time
   java.lang.System.currentTimeMillis();
   
3. Date
   java.util.Date.
   It is a date/time operation util, you can use this class to get day, month, ...
   
4. Date format
   
   • Get user configured date format
     DateFormat.getDateFormat(context);
     
   • Get week day strings
     DateFormatSymbols dfs = new DateFormatSymbols();
     String monday = dfs.getWeekDays[Calendar.MONDAY];
     String sunday = dfs.getWeekDays[Calendar.SUNDAY];
     
   • xxx
     
5. Calendar
   java.util.Calendar.
   
6. TimeZone
   java.util.TimeZone
   
7. Dialog
   
   • DatePicker\DatePickerDialog
   • TimePicker\TimePickerDialog
8. xxx