This class takes as inputs a format string and a representation of a date/time. The format string controls how the output is generated.
Formatting characters may be repeated in order to get more detailed representations of that field. For instance, the format character 'M' is used to represent the month. Depending on how many times that character is repeated you get a different representation.
For the month of September:
M -> 9
MM -> 09
MMM -> Sep
MMMM -> September
The effects of the duplication vary depending on the nature of the field.
See the notes on the individual field formatters for details. For purely numeric
fields such as HOUR adding more copies of the designator will
zero-pad the value to that number of characters.
For 7 minutes past the hour:
m -> 7
mm -> 07
mmm -> 007
mmmm -> 0007
Examples for April 6, 1970 at 3:23am:
"MM/dd/yy h:mmaa" -> "04/06/70 3:23am"
"MMM dd, yyyy h:mmaa" -> "Apr 6, 1970 3:23am"
"MMMM dd, yyyy h:mmaa" -> "April 6, 1970 3:23am"
"E, MMMM dd, yyyy h:mmaa" -> "Mon, April 6, 1970 3:23am&
"EEEE, MMMM dd, yyyy h:mmaa" -> "Monday, April 6, 1970 3:23am"
"'Noteworthy day: 'M/d/yy" -> "Noteworthy day: 4/6/70"
*/
public class DateFormat {
/**
Text in the format string that should be copied verbatim rather that
interpreted as formatting codes must be surrounded by the QUOTE
character. If you need to embed a literal QUOTE character in
the output text then use two in a row.
*/
public static final char QUOTE = '\'';
/**
This designator indicates whether the HOUR field is before
or after noon. The output is lower-case.
Examples:
a -> a or p
aa -> am or pm
*/
public static final char AM_PM = 'a';
/**
This designator indicates whether the HOUR field is before
or after noon. The output is capitalized.
Examples:
A -> A or P
AA -> AM or PM
*/
public static final char CAPITAL_AM_PM = 'A';
/**
This designator indicates the day of the month.
Examples for the 9th of the month:
d -> 9
dd -> 09
*/
public static final char DATE = 'd';
/**
This designator indicates the name of the day of the week.
Examples for Sunday:
E -> Sun
EEEE -> Sunday
*/
public static final char DAY = 'E';
/**
This designator indicates the hour of the day in 12 hour format.
Examples for 3pm:
h -> 3
hh -> 03
*/
public static final char HOUR = 'h';
/**
This designator indicates the hour of the day in 24 hour format.
Example for 3pm:
k -> 15
Examples for midnight:
k -> 0
kk -> 00
*/
public static final char HOUR_OF_DAY = 'k';
/**
This designator indicates the minute of the hour.
Examples for 7 minutes past the hour:
m -> 7
mm -> 07
*/
public static final char MINUTE = 'm';
/**
This designator indicates the month of the year
Examples for September:
M -> 9
MM -> 09
MMM -> Sep
MMMM -> September
*/
public static final char MONTH = 'M';
/**
This designator indicates the seconds of the minute.
Examples for 7 seconds past the minute:
s -> 7
ss -> 07
*/
public static final char SECONDS = 's';
/**
This designator indicates the offset of the timezone from GMT.
Example for US/Pacific timezone:
z -> -0800
zz -> PST
*/
public static final char TIME_ZONE = 'z';
/**
This designator indicates the year.
Examples for 2006
y -> 06
yyyy -> 2006
*/
public static final char YEAR = 'y';
private static final Object sLocaleLock = new Object();
private static Locale sIs24HourLocale;
private static boolean sIs24Hour;
/**
* Returns true if user preference is set to 24-hour format.
* @param context the context to use for the content resolver
* @return true if 24 hour time format is selected, false otherwise.
*/
public static boolean is24HourFormat(Context context) {
String value = Settings.System.getString(context.getContentResolver(),
Settings.System.TIME_12_24);
if (value == null) {
Locale locale = context.getResources().getConfiguration().locale;
synchronized (sLocaleLock) {
if (sIs24HourLocale != null && sIs24HourLocale.equals(locale)) {
return sIs24Hour;
}
}
java.text.DateFormat natural =
java.text.DateFormat.getTimeInstance(
java.text.DateFormat.LONG, locale);
if (natural instanceof SimpleDateFormat) {
SimpleDateFormat sdf = (SimpleDateFormat) natural;
String pattern = sdf.toPattern();
if (pattern.indexOf('H') >= 0) {
value = "24";
} else {
value = "12";
}
} else {
value = "12";
}
synchronized (sLocaleLock) {
sIs24HourLocale = locale;
sIs24Hour = !value.equals("12");
}
}
boolean b24 = !(value == null || value.equals("12"));
return b24;
}
/**
* Returns a {@link java.text.DateFormat} object that can format the time according
* to the current locale and the user's 12-/24-hour clock preference.
* @param context the application context
* @return the {@link java.text.DateFormat} object that properly formats the time.
*/
public static final java.text.DateFormat getTimeFormat(Context context) {
boolean b24 = is24HourFormat(context);
int res;
if (b24) {
res = R.string.twenty_four_hour_time_format;
} else {
res = R.string.twelve_hour_time_format;
}
return new java.text.SimpleDateFormat(context.getString(res));
}
/**
* Returns a {@link java.text.DateFormat} object that can format the date
* in short form (such as 12/31/1999) according
* to the current locale and the user's date-order preference.
* @param context the application context
* @return the {@link java.text.DateFormat} object that properly formats the date.
*/
public static final java.text.DateFormat getDateFormat(Context context) {
String value = Settings.System.getString(context.getContentResolver(),
Settings.System.DATE_FORMAT);
return getDateFormatForSetting(context, value);
}
/**
* Returns a {@link java.text.DateFormat} object to format the date
* as if the date format setting were set to value,
* including null to use the locale's default format.
* @param context the application context
* @param value the date format setting string to interpret for
* the current locale
* @hide
*/
public static java.text.DateFormat getDateFormatForSetting(Context context,
String value) {
String format = getDateFormatStringForSetting(context, value);
return new java.text.SimpleDateFormat(format);
}
private static String getDateFormatStringForSetting(Context context, String value) {
if (value != null) {
int month = value.indexOf('M');
int day = value.indexOf('d');
int year = value.indexOf('y');
if (month >= 0 && day >= 0 && year >= 0) {
String template = context.getString(R.string.numeric_date_template);
if (year < month && year < day) {
if (month < day) {
value = String.format(template, "yyyy", "MM", "dd");
} else {
value = String.format(template, "yyyy", "dd", "MM");
}
} else if (month < day) {
if (day < year) {
value = String.format(template, "MM", "dd", "yyyy");
} else { // unlikely
value = String.format(template, "MM", "yyyy", "dd");
}
} else { // day < month
if (month < year) {
value = String.format(template, "dd", "MM", "yyyy");
} else { // unlikely
value = String.format(template, "dd", "yyyy", "MM");
}
}
return value;
}
}
/*
* The setting is not set; use the default.
* We use a resource string here instead of just DateFormat.SHORT
* so that we get a four-digit year instead a two-digit year.
*/
value = context.getString(R.string.numeric_date_format);
return value;
}
/**
* Returns a {@link java.text.DateFormat} object that can format the date
* in long form (such as December 31, 1999) for the current locale.
* @param context the application context
* @return the {@link java.text.DateFormat} object that formats the date in long form.
*/
public static final java.text.DateFormat getLongDateFormat(Context context) {
return java.text.DateFormat.getDateInstance(java.text.DateFormat.LONG);
}
/**
* Returns a {@link java.text.DateFormat} object that can format the date
* in medium form (such as Dec. 31, 1999) for the current locale.
* @param context the application context
* @return the {@link java.text.DateFormat} object that formats the date in long form.
*/
public static final java.text.DateFormat getMediumDateFormat(Context context) {
return java.text.DateFormat.getDateInstance(java.text.DateFormat.MEDIUM);
}
/**
* Gets the current date format stored as a char array. The array will contain
* 3 elements ({@link #DATE}, {@link #MONTH}, and {@link #YEAR}) in the order
* specified by the user's format preference. Note that this order is
* only appropriate for all-numeric dates; spelled-out (MEDIUM and LONG)
* dates will generally contain other punctuation, spaces, or words,
* not just the day, month, and year, and not necessarily in the same
* order returned here.
*/
public static final char[] getDateFormatOrder(Context context) {
char[] order = new char[] {DATE, MONTH, YEAR};
String value = getDateFormatString(context);
int index = 0;
boolean foundDate = false;
boolean foundMonth = false;
boolean foundYear = false;
for (char c : value.toCharArray()) {
if (!foundDate && (c == DATE)) {
foundDate = true;
order[index] = DATE;
index++;
}
if (!foundMonth && (c == MONTH)) {
foundMonth = true;
order[index] = MONTH;
index++;
}
if (!foundYear && (c == YEAR)) {
foundYear = true;
order[index] = YEAR;
index++;
}
}
return order;
}
private static String getDateFormatString(Context context) {
String value = Settings.System.getString(context.getContentResolver(),
Settings.System.DATE_FORMAT);
return getDateFormatStringForSetting(context, value);
}
/**
* Given a format string and a time in milliseconds since Jan 1, 1970 GMT, returns a
* CharSequence containing the requested date.
* @param inFormat the format string, as described in {@link android.text.format.DateFormat}
* @param inTimeInMillis in milliseconds since Jan 1, 1970 GMT
* @return a {@link CharSequence} containing the requested text
*/
public static final CharSequence format(CharSequence inFormat, long inTimeInMillis) {
return format(inFormat, new Date(inTimeInMillis));
}
/**
* Given a format string and a {@link java.util.Date} object, returns a CharSequence containing
* the requested date.
* @param inFormat the format string, as described in {@link android.text.format.DateFormat}
* @param inDate the date to format
* @return a {@link CharSequence} containing the requested text
*/
public static final CharSequence format(CharSequence inFormat, Date inDate) {
Calendar c = new GregorianCalendar();
c.setTime(inDate);
return format(inFormat, c);
}
/**
* Given a format string and a {@link java.util.Calendar} object, returns a CharSequence
* containing the requested date.
* @param inFormat the format string, as described in {@link android.text.format.DateFormat}
* @param inDate the date to format
* @return a {@link CharSequence} containing the requested text
*/
public static final CharSequence format(CharSequence inFormat, Calendar inDate) {
SpannableStringBuilder s = new SpannableStringBuilder(inFormat);
int c;
int count;
int len = inFormat.length();
for (int i = 0; i < len; i += count) {
int temp;
count = 1;
c = s.charAt(i);
if (c == QUOTE) {
count = appendQuotedText(s, i, len);
len = s.length();
continue;
}
while ((i + count < len) && (s.charAt(i + count) == c)) {
count++;
}
String replacement;
switch (c) {
case AM_PM:
replacement = DateUtils.getAMPMString(inDate.get(Calendar.AM_PM));
break;
case CAPITAL_AM_PM:
//FIXME: this is the same as AM_PM? no capital?
replacement = DateUtils.getAMPMString(inDate.get(Calendar.AM_PM));
break;
case DATE:
replacement = zeroPad(inDate.get(Calendar.DATE), count);
break;
case DAY:
temp = inDate.get(Calendar.DAY_OF_WEEK);
replacement = DateUtils.getDayOfWeekString(temp,
count < 4 ?
DateUtils.LENGTH_MEDIUM :
DateUtils.LENGTH_LONG);
break;
case HOUR:
temp = inDate.get(Calendar.HOUR);
if (0 == temp)
temp = 12;
replacement = zeroPad(temp, count);
break;
case HOUR_OF_DAY:
replacement = zeroPad(inDate.get(Calendar.HOUR_OF_DAY), count);
break;
case MINUTE:
replacement = zeroPad(inDate.get(Calendar.MINUTE), count);
break;
case MONTH:
replacement = getMonthString(inDate, count);
break;
case SECONDS:
replacement = zeroPad(inDate.get(Calendar.SECOND), count);
break;
case TIME_ZONE:
replacement = getTimeZoneString(inDate, count);
break;
case YEAR:
replacement = getYearString(inDate, count);
break;
default:
replacement = null;
break;
}
if (replacement != null) {
s.replace(i, i + count, replacement);
count = replacement.length(); // CARE: count is used in the for loop above
len = s.length();
}
}
if (inFormat instanceof Spanned)
return new SpannedString(s);
else
return s.toString();
}
private static final String getMonthString(Calendar inDate, int count) {
int month = inDate.get(Calendar.MONTH);
if (count >= 4)
return DateUtils.getMonthString(month, DateUtils.LENGTH_LONG);
else if (count == 3)
return DateUtils.getMonthString(month, DateUtils.LENGTH_MEDIUM);
else {
// Calendar.JANUARY == 0, so add 1 to month.
return zeroPad(month+1, count);
}
}
private static final String getTimeZoneString(Calendar inDate, int count) {
TimeZone tz = inDate.getTimeZone();
if (count < 2) { // FIXME: shouldn't this be <= 2 ?
return formatZoneOffset(inDate.get(Calendar.DST_OFFSET) +
inDate.get(Calendar.ZONE_OFFSET),
count);
} else {
boolean dst = inDate.get(Calendar.DST_OFFSET) != 0;
return tz.getDisplayName(dst, TimeZone.SHORT);
}
}
private static final String formatZoneOffset(int offset, int count) {
offset /= 1000; // milliseconds to seconds
StringBuilder tb = new StringBuilder();
if (offset < 0) {
tb.insert(0, "-");
offset = -offset;
} else {
tb.insert(0, "+");
}
int hours = offset / 3600;
int minutes = (offset % 3600) / 60;
tb.append(zeroPad(hours, 2));
tb.append(zeroPad(minutes, 2));
return tb.toString();
}
private static final String getYearString(Calendar inDate, int count) {
int year = inDate.get(Calendar.YEAR);
return (count <= 2) ? zeroPad(year % 100, 2) : String.valueOf(year);
}
private static final int appendQuotedText(SpannableStringBuilder s, int i, int len) {
if (i + 1 < len && s.charAt(i + 1) == QUOTE) {
s.delete(i, i + 1);
return 1;
}
int count = 0;
// delete leading quote
s.delete(i, i + 1);
len--;
while (i < len) {
char c = s.charAt(i);
if (c == QUOTE) {
// QUOTEQUOTE -> QUOTE
if (i + 1 < len && s.charAt(i + 1) == QUOTE) {
s.delete(i, i + 1);
len--;
count++;
i++;
} else {
// Closing QUOTE ends quoted text copying
s.delete(i, i + 1);
break;
}
} else {
i++;
count++;
}
}
return count;
}
private static final String zeroPad(int inValue, int inMinDigits) {
String val = String.valueOf(inValue);
if (val.length() < inMinDigits) {
char[] buf = new char[inMinDigits];
for (int i = 0; i < inMinDigits; i++)
buf[i] = '0';
val.getChars(0, val.length(), buf, inMinDigits - val.length());
val = new String(buf);
}
return val;
}
}