DateUtils.java revision 5669ce59aad19f17e1e89913e7483fb93b8aa0cf
1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.text.format;
18
19import com.android.internal.R;
20
21import android.content.Context;
22import android.content.res.Configuration;
23import android.content.res.Resources;
24import android.pim.DateException;
25
26import java.util.Calendar;
27import java.util.Date;
28import java.util.GregorianCalendar;
29import java.util.TimeZone;
30
31/**
32 * This class contains various date-related utilities for creating text for things like
33 * elapsed time and date ranges, strings for days of the week and months, and AM/PM text etc.
34 */
35public class DateUtils
36{
37    private static final Object sLock = new Object();
38    private static final int[] sDaysLong = new int[] {
39            com.android.internal.R.string.day_of_week_long_sunday,
40            com.android.internal.R.string.day_of_week_long_monday,
41            com.android.internal.R.string.day_of_week_long_tuesday,
42            com.android.internal.R.string.day_of_week_long_wednesday,
43            com.android.internal.R.string.day_of_week_long_thursday,
44            com.android.internal.R.string.day_of_week_long_friday,
45            com.android.internal.R.string.day_of_week_long_saturday,
46        };
47    private static final int[] sDaysMedium = new int[] {
48            com.android.internal.R.string.day_of_week_medium_sunday,
49            com.android.internal.R.string.day_of_week_medium_monday,
50            com.android.internal.R.string.day_of_week_medium_tuesday,
51            com.android.internal.R.string.day_of_week_medium_wednesday,
52            com.android.internal.R.string.day_of_week_medium_thursday,
53            com.android.internal.R.string.day_of_week_medium_friday,
54            com.android.internal.R.string.day_of_week_medium_saturday,
55        };
56    private static final int[] sDaysShort = new int[] {
57            com.android.internal.R.string.day_of_week_short_sunday,
58            com.android.internal.R.string.day_of_week_short_monday,
59            com.android.internal.R.string.day_of_week_short_tuesday,
60            com.android.internal.R.string.day_of_week_short_wednesday,
61            com.android.internal.R.string.day_of_week_short_thursday,
62            com.android.internal.R.string.day_of_week_short_friday,
63            com.android.internal.R.string.day_of_week_short_saturday,
64        };
65    private static final int[] sDaysShortest = new int[] {
66            com.android.internal.R.string.day_of_week_shortest_sunday,
67            com.android.internal.R.string.day_of_week_shortest_monday,
68            com.android.internal.R.string.day_of_week_shortest_tuesday,
69            com.android.internal.R.string.day_of_week_shortest_wednesday,
70            com.android.internal.R.string.day_of_week_shortest_thursday,
71            com.android.internal.R.string.day_of_week_shortest_friday,
72            com.android.internal.R.string.day_of_week_shortest_saturday,
73        };
74    private static final int[] sMonthsStandaloneLong = new int [] {
75            com.android.internal.R.string.month_long_standalone_january,
76            com.android.internal.R.string.month_long_standalone_february,
77            com.android.internal.R.string.month_long_standalone_march,
78            com.android.internal.R.string.month_long_standalone_april,
79            com.android.internal.R.string.month_long_standalone_may,
80            com.android.internal.R.string.month_long_standalone_june,
81            com.android.internal.R.string.month_long_standalone_july,
82            com.android.internal.R.string.month_long_standalone_august,
83            com.android.internal.R.string.month_long_standalone_september,
84            com.android.internal.R.string.month_long_standalone_october,
85            com.android.internal.R.string.month_long_standalone_november,
86            com.android.internal.R.string.month_long_standalone_december,
87        };
88    private static final int[] sMonthsLong = new int [] {
89            com.android.internal.R.string.month_long_january,
90            com.android.internal.R.string.month_long_february,
91            com.android.internal.R.string.month_long_march,
92            com.android.internal.R.string.month_long_april,
93            com.android.internal.R.string.month_long_may,
94            com.android.internal.R.string.month_long_june,
95            com.android.internal.R.string.month_long_july,
96            com.android.internal.R.string.month_long_august,
97            com.android.internal.R.string.month_long_september,
98            com.android.internal.R.string.month_long_october,
99            com.android.internal.R.string.month_long_november,
100            com.android.internal.R.string.month_long_december,
101        };
102    private static final int[] sMonthsMedium = new int [] {
103            com.android.internal.R.string.month_medium_january,
104            com.android.internal.R.string.month_medium_february,
105            com.android.internal.R.string.month_medium_march,
106            com.android.internal.R.string.month_medium_april,
107            com.android.internal.R.string.month_medium_may,
108            com.android.internal.R.string.month_medium_june,
109            com.android.internal.R.string.month_medium_july,
110            com.android.internal.R.string.month_medium_august,
111            com.android.internal.R.string.month_medium_september,
112            com.android.internal.R.string.month_medium_october,
113            com.android.internal.R.string.month_medium_november,
114            com.android.internal.R.string.month_medium_december,
115        };
116    private static final int[] sMonthsShortest = new int [] {
117            com.android.internal.R.string.month_shortest_january,
118            com.android.internal.R.string.month_shortest_february,
119            com.android.internal.R.string.month_shortest_march,
120            com.android.internal.R.string.month_shortest_april,
121            com.android.internal.R.string.month_shortest_may,
122            com.android.internal.R.string.month_shortest_june,
123            com.android.internal.R.string.month_shortest_july,
124            com.android.internal.R.string.month_shortest_august,
125            com.android.internal.R.string.month_shortest_september,
126            com.android.internal.R.string.month_shortest_october,
127            com.android.internal.R.string.month_shortest_november,
128            com.android.internal.R.string.month_shortest_december,
129        };
130    private static final int[] sAmPm = new int[] {
131            com.android.internal.R.string.am,
132            com.android.internal.R.string.pm,
133        };
134    private static Configuration sLastConfig;
135    private static java.text.DateFormat sStatusTimeFormat;
136    private static String sElapsedFormatMMSS;
137    private static String sElapsedFormatHMMSS;
138
139    private static final String FAST_FORMAT_HMMSS = "%1$d:%2$02d:%3$02d";
140    private static final String FAST_FORMAT_MMSS = "%1$02d:%2$02d";
141    private static final char TIME_PADDING = '0';
142    private static final char TIME_SEPARATOR = ':';
143
144
145    public static final long SECOND_IN_MILLIS = 1000;
146    public static final long MINUTE_IN_MILLIS = SECOND_IN_MILLIS * 60;
147    public static final long HOUR_IN_MILLIS = MINUTE_IN_MILLIS * 60;
148    public static final long DAY_IN_MILLIS = HOUR_IN_MILLIS * 24;
149    public static final long WEEK_IN_MILLIS = DAY_IN_MILLIS * 7;
150    /**
151     * This constant is actually the length of 364 days, not of a year!
152     */
153    public static final long YEAR_IN_MILLIS = WEEK_IN_MILLIS * 52;
154
155    // The following FORMAT_* symbols are used for specifying the format of
156    // dates and times in the formatDateRange method.
157    public static final int FORMAT_SHOW_TIME = 0x00001;
158    public static final int FORMAT_SHOW_WEEKDAY = 0x00002;
159    public static final int FORMAT_SHOW_YEAR = 0x00004;
160    public static final int FORMAT_NO_YEAR = 0x00008;
161    public static final int FORMAT_SHOW_DATE = 0x00010;
162    public static final int FORMAT_NO_MONTH_DAY = 0x00020;
163    public static final int FORMAT_12HOUR = 0x00040;
164    public static final int FORMAT_24HOUR = 0x00080;
165    public static final int FORMAT_CAP_AMPM = 0x00100;
166    public static final int FORMAT_NO_NOON = 0x00200;
167    public static final int FORMAT_CAP_NOON = 0x00400;
168    public static final int FORMAT_NO_MIDNIGHT = 0x00800;
169    public static final int FORMAT_CAP_MIDNIGHT = 0x01000;
170    public static final int FORMAT_UTC = 0x02000;
171    public static final int FORMAT_ABBREV_TIME = 0x04000;
172    public static final int FORMAT_ABBREV_WEEKDAY = 0x08000;
173    public static final int FORMAT_ABBREV_MONTH = 0x10000;
174    public static final int FORMAT_NUMERIC_DATE = 0x20000;
175    public static final int FORMAT_ABBREV_RELATIVE = 0x40000;
176    public static final int FORMAT_ABBREV_ALL = 0x80000;
177    public static final int FORMAT_CAP_NOON_MIDNIGHT = (FORMAT_CAP_NOON | FORMAT_CAP_MIDNIGHT);
178    public static final int FORMAT_NO_NOON_MIDNIGHT = (FORMAT_NO_NOON | FORMAT_NO_MIDNIGHT);
179
180    // Date and time format strings that are constant and don't need to be
181    // translated.
182    /**
183     * This is not actually the preferred 24-hour date format in all locales.
184     */
185    public static final String HOUR_MINUTE_24 = "%H:%M";
186    public static final String MONTH_FORMAT = "%B";
187    /**
188     * This is not actually a useful month name in all locales.
189     */
190    public static final String ABBREV_MONTH_FORMAT = "%b";
191    public static final String NUMERIC_MONTH_FORMAT = "%m";
192    public static final String MONTH_DAY_FORMAT = "%-d";
193    public static final String YEAR_FORMAT = "%Y";
194    public static final String YEAR_FORMAT_TWO_DIGITS = "%g";
195    public static final String WEEKDAY_FORMAT = "%A";
196    public static final String ABBREV_WEEKDAY_FORMAT = "%a";
197
198    // This table is used to lookup the resource string id of a format string
199    // used for formatting a start and end date that fall in the same year.
200    // The index is constructed from a bit-wise OR of the boolean values:
201    // {showTime, showYear, showWeekDay}.  For example, if showYear and
202    // showWeekDay are both true, then the index would be 3.
203    public static final int sameYearTable[] = {
204        com.android.internal.R.string.same_year_md1_md2,
205        com.android.internal.R.string.same_year_wday1_md1_wday2_md2,
206        com.android.internal.R.string.same_year_mdy1_mdy2,
207        com.android.internal.R.string.same_year_wday1_mdy1_wday2_mdy2,
208        com.android.internal.R.string.same_year_md1_time1_md2_time2,
209        com.android.internal.R.string.same_year_wday1_md1_time1_wday2_md2_time2,
210        com.android.internal.R.string.same_year_mdy1_time1_mdy2_time2,
211        com.android.internal.R.string.same_year_wday1_mdy1_time1_wday2_mdy2_time2,
212
213        // Numeric date strings
214        com.android.internal.R.string.numeric_md1_md2,
215        com.android.internal.R.string.numeric_wday1_md1_wday2_md2,
216        com.android.internal.R.string.numeric_mdy1_mdy2,
217        com.android.internal.R.string.numeric_wday1_mdy1_wday2_mdy2,
218        com.android.internal.R.string.numeric_md1_time1_md2_time2,
219        com.android.internal.R.string.numeric_wday1_md1_time1_wday2_md2_time2,
220        com.android.internal.R.string.numeric_mdy1_time1_mdy2_time2,
221        com.android.internal.R.string.numeric_wday1_mdy1_time1_wday2_mdy2_time2,
222    };
223
224    // This table is used to lookup the resource string id of a format string
225    // used for formatting a start and end date that fall in the same month.
226    // The index is constructed from a bit-wise OR of the boolean values:
227    // {showTime, showYear, showWeekDay}.  For example, if showYear and
228    // showWeekDay are both true, then the index would be 3.
229    public static final int sameMonthTable[] = {
230        com.android.internal.R.string.same_month_md1_md2,
231        com.android.internal.R.string.same_month_wday1_md1_wday2_md2,
232        com.android.internal.R.string.same_month_mdy1_mdy2,
233        com.android.internal.R.string.same_month_wday1_mdy1_wday2_mdy2,
234        com.android.internal.R.string.same_month_md1_time1_md2_time2,
235        com.android.internal.R.string.same_month_wday1_md1_time1_wday2_md2_time2,
236        com.android.internal.R.string.same_month_mdy1_time1_mdy2_time2,
237        com.android.internal.R.string.same_month_wday1_mdy1_time1_wday2_mdy2_time2,
238
239        com.android.internal.R.string.numeric_md1_md2,
240        com.android.internal.R.string.numeric_wday1_md1_wday2_md2,
241        com.android.internal.R.string.numeric_mdy1_mdy2,
242        com.android.internal.R.string.numeric_wday1_mdy1_wday2_mdy2,
243        com.android.internal.R.string.numeric_md1_time1_md2_time2,
244        com.android.internal.R.string.numeric_wday1_md1_time1_wday2_md2_time2,
245        com.android.internal.R.string.numeric_mdy1_time1_mdy2_time2,
246        com.android.internal.R.string.numeric_wday1_mdy1_time1_wday2_mdy2_time2,
247    };
248
249    /**
250     * Request the full spelled-out name. For use with the 'abbrev' parameter of
251     * {@link #getDayOfWeekString} and {@link #getMonthString}.
252     *
253     * @more <p>
254     *       e.g. "Sunday" or "January"
255     */
256    public static final int LENGTH_LONG = 10;
257
258    /**
259     * Request an abbreviated version of the name. For use with the 'abbrev'
260     * parameter of {@link #getDayOfWeekString} and {@link #getMonthString}.
261     *
262     * @more <p>
263     *       e.g. "Sun" or "Jan"
264     */
265    public static final int LENGTH_MEDIUM = 20;
266
267    /**
268     * Request a shorter abbreviated version of the name.
269     * For use with the 'abbrev' parameter of {@link #getDayOfWeekString} and {@link #getMonthString}.
270     * @more
271     * <p>e.g. "Su" or "Jan"
272     * <p>In most languages, the results returned for LENGTH_SHORT will be the same as
273     * the results returned for {@link #LENGTH_MEDIUM}.
274     */
275    public static final int LENGTH_SHORT = 30;
276
277    /**
278     * Request an even shorter abbreviated version of the name.
279     * Do not use this.  Currently this will always return the same result
280     * as {@link #LENGTH_SHORT}.
281     */
282    public static final int LENGTH_SHORTER = 40;
283
284    /**
285     * Request an even shorter abbreviated version of the name.
286     * For use with the 'abbrev' parameter of {@link #getDayOfWeekString} and {@link #getMonthString}.
287     * @more
288     * <p>e.g. "S", "T", "T" or "J"
289     * <p>In some languages, the results returned for LENGTH_SHORTEST will be the same as
290     * the results returned for {@link #LENGTH_SHORT}.
291     */
292    public static final int LENGTH_SHORTEST = 50;
293
294    /**
295     * Return a string for the day of the week.
296     * @param dayOfWeek One of {@link Calendar#SUNDAY Calendar.SUNDAY},
297     *               {@link Calendar#MONDAY Calendar.MONDAY}, etc.
298     * @param abbrev One of {@link #LENGTH_LONG}, {@link #LENGTH_SHORT},
299     *               {@link #LENGTH_MEDIUM}, or {@link #LENGTH_SHORTEST}.
300     *               Note that in most languages, {@link #LENGTH_SHORT}
301     *               will return the same as {@link #LENGTH_MEDIUM}.
302     *               Undefined lengths will return {@link #LENGTH_MEDIUM}
303     *               but may return something different in the future.
304     * @throws IndexOutOfBoundsException if the dayOfWeek is out of bounds.
305     */
306    public static String getDayOfWeekString(int dayOfWeek, int abbrev) {
307        int[] list;
308        switch (abbrev) {
309            case LENGTH_LONG:       list = sDaysLong;       break;
310            case LENGTH_MEDIUM:     list = sDaysMedium;     break;
311            case LENGTH_SHORT:      list = sDaysShort;      break;
312            case LENGTH_SHORTER:    list = sDaysShort;      break;
313            case LENGTH_SHORTEST:   list = sDaysShortest;   break;
314            default:                list = sDaysMedium;     break;
315        }
316
317        Resources r = Resources.getSystem();
318        return r.getString(list[dayOfWeek - Calendar.SUNDAY]);
319    }
320
321    /**
322     * Return a localized string for AM or PM.
323     * @param ampm Either {@link Calendar#AM Calendar.AM} or {@link Calendar#PM Calendar.PM}.
324     * @throws IndexOutOfBoundsException if the ampm is out of bounds.
325     * @return Localized version of "AM" or "PM".
326     */
327    public static String getAMPMString(int ampm) {
328        Resources r = Resources.getSystem();
329        return r.getString(sAmPm[ampm - Calendar.AM]);
330    }
331
332    /**
333     * Return a localized string for the month of the year.
334     * @param month One of {@link Calendar#JANUARY Calendar.JANUARY},
335     *               {@link Calendar#FEBRUARY Calendar.FEBRUARY}, etc.
336     * @param abbrev One of {@link #LENGTH_LONG}, {@link #LENGTH_MEDIUM},
337     *               or {@link #LENGTH_SHORTEST}.
338     *               Undefined lengths will return {@link #LENGTH_MEDIUM}
339     *               but may return something different in the future.
340     * @return Localized month of the year.
341     */
342    public static String getMonthString(int month, int abbrev) {
343        // Note that here we use sMonthsMedium for MEDIUM, SHORT and SHORTER.
344        // This is a shortcut to not spam the translators with too many variations
345        // of the same string.  If we find that in a language the distinction
346        // is necessary, we can can add more without changing this API.
347        int[] list;
348        switch (abbrev) {
349            case LENGTH_LONG:       list = sMonthsLong;     break;
350            case LENGTH_MEDIUM:     list = sMonthsMedium;   break;
351            case LENGTH_SHORT:      list = sMonthsMedium;   break;
352            case LENGTH_SHORTER:    list = sMonthsMedium;   break;
353            case LENGTH_SHORTEST:   list = sMonthsShortest; break;
354            default:                list = sMonthsMedium;   break;
355        }
356
357        Resources r = Resources.getSystem();
358        return r.getString(list[month - Calendar.JANUARY]);
359    }
360
361    /**
362     * Return a localized string for the month of the year, for
363     * contexts where the month is not formatted together with
364     * a day of the month.
365     *
366     * @param month One of {@link Calendar#JANUARY Calendar.JANUARY},
367     *               {@link Calendar#FEBRUARY Calendar.FEBRUARY}, etc.
368     * @param abbrev One of {@link #LENGTH_LONG}, {@link #LENGTH_MEDIUM},
369     *               or {@link #LENGTH_SHORTEST}.
370     *               Undefined lengths will return {@link #LENGTH_MEDIUM}
371     *               but may return something different in the future.
372     * @return Localized month of the year.
373     * @hide Pending API council approval
374     */
375    public static String getStandaloneMonthString(int month, int abbrev) {
376        // Note that here we use sMonthsMedium for MEDIUM, SHORT and SHORTER.
377        // This is a shortcut to not spam the translators with too many variations
378        // of the same string.  If we find that in a language the distinction
379        // is necessary, we can can add more without changing this API.
380        int[] list;
381        switch (abbrev) {
382            case LENGTH_LONG:       list = sMonthsStandaloneLong;
383                                                            break;
384            case LENGTH_MEDIUM:     list = sMonthsMedium;   break;
385            case LENGTH_SHORT:      list = sMonthsMedium;   break;
386            case LENGTH_SHORTER:    list = sMonthsMedium;   break;
387            case LENGTH_SHORTEST:   list = sMonthsShortest; break;
388            default:                list = sMonthsMedium;   break;
389        }
390
391        Resources r = Resources.getSystem();
392        return r.getString(list[month - Calendar.JANUARY]);
393    }
394
395    /**
396     * Returns a string describing the elapsed time since startTime.
397     * @param startTime some time in the past.
398     * @return a String object containing the elapsed time.
399     * @see #getRelativeTimeSpanString(long, long, long)
400     */
401    public static CharSequence getRelativeTimeSpanString(long startTime) {
402        return getRelativeTimeSpanString(startTime, System.currentTimeMillis(), MINUTE_IN_MILLIS);
403    }
404
405    /**
406     * Returns a string describing 'time' as a time relative to 'now'.
407     * <p>
408     * Time spans in the past are formatted like "42 minutes ago".
409     * Time spans in the future are formatted like "in 42 minutes".
410     *
411     * @param time the time to describe, in milliseconds
412     * @param now the current time in milliseconds
413     * @param minResolution the minimum timespan to report. For example, a time 3 seconds in the
414     *     past will be reported as "0 minutes ago" if this is set to MINUTE_IN_MILLIS. Pass one of
415     *     0, MINUTE_IN_MILLIS, HOUR_IN_MILLIS, DAY_IN_MILLIS, WEEK_IN_MILLIS
416     */
417    public static CharSequence getRelativeTimeSpanString(long time, long now, long minResolution) {
418        int flags = FORMAT_SHOW_DATE | FORMAT_SHOW_YEAR | FORMAT_ABBREV_MONTH;
419        return getRelativeTimeSpanString(time, now, minResolution, flags);
420    }
421
422    /**
423     * Returns a string describing 'time' as a time relative to 'now'.
424     * <p>
425     * Time spans in the past are formatted like "42 minutes ago". Time spans in
426     * the future are formatted like "in 42 minutes".
427     * <p>
428     * Can use {@link #FORMAT_ABBREV_RELATIVE} flag to use abbreviated relative
429     * times, like "42 mins ago".
430     *
431     * @param time the time to describe, in milliseconds
432     * @param now the current time in milliseconds
433     * @param minResolution the minimum timespan to report. For example, a time
434     *            3 seconds in the past will be reported as "0 minutes ago" if
435     *            this is set to MINUTE_IN_MILLIS. Pass one of 0,
436     *            MINUTE_IN_MILLIS, HOUR_IN_MILLIS, DAY_IN_MILLIS,
437     *            WEEK_IN_MILLIS
438     * @param flags a bit mask of formatting options, such as
439     *            {@link #FORMAT_NUMERIC_DATE} or
440     *            {@link #FORMAT_ABBREV_RELATIVE}
441     */
442    public static CharSequence getRelativeTimeSpanString(long time, long now, long minResolution,
443            int flags) {
444        Resources r = Resources.getSystem();
445        boolean abbrevRelative = (flags & (FORMAT_ABBREV_RELATIVE | FORMAT_ABBREV_ALL)) != 0;
446
447        boolean past = (now >= time);
448        long duration = Math.abs(now - time);
449
450        int resId;
451        long count;
452        if (duration < MINUTE_IN_MILLIS && minResolution < MINUTE_IN_MILLIS) {
453            count = duration / SECOND_IN_MILLIS;
454            if (past) {
455                if (abbrevRelative) {
456                    resId = com.android.internal.R.plurals.abbrev_num_seconds_ago;
457                } else {
458                    resId = com.android.internal.R.plurals.num_seconds_ago;
459                }
460            } else {
461                if (abbrevRelative) {
462                    resId = com.android.internal.R.plurals.abbrev_in_num_seconds;
463                } else {
464                    resId = com.android.internal.R.plurals.in_num_seconds;
465                }
466            }
467        } else if (duration < HOUR_IN_MILLIS && minResolution < HOUR_IN_MILLIS) {
468            count = duration / MINUTE_IN_MILLIS;
469            if (past) {
470                if (abbrevRelative) {
471                    resId = com.android.internal.R.plurals.abbrev_num_minutes_ago;
472                } else {
473                    resId = com.android.internal.R.plurals.num_minutes_ago;
474                }
475            } else {
476                if (abbrevRelative) {
477                    resId = com.android.internal.R.plurals.abbrev_in_num_minutes;
478                } else {
479                    resId = com.android.internal.R.plurals.in_num_minutes;
480                }
481            }
482        } else if (duration < DAY_IN_MILLIS && minResolution < DAY_IN_MILLIS) {
483            count = duration / HOUR_IN_MILLIS;
484            if (past) {
485                if (abbrevRelative) {
486                    resId = com.android.internal.R.plurals.abbrev_num_hours_ago;
487                } else {
488                    resId = com.android.internal.R.plurals.num_hours_ago;
489                }
490            } else {
491                if (abbrevRelative) {
492                    resId = com.android.internal.R.plurals.abbrev_in_num_hours;
493                } else {
494                    resId = com.android.internal.R.plurals.in_num_hours;
495                }
496            }
497        } else if (duration < WEEK_IN_MILLIS && minResolution < WEEK_IN_MILLIS) {
498            count = duration / DAY_IN_MILLIS;
499            if (past) {
500                if (abbrevRelative) {
501                    resId = com.android.internal.R.plurals.abbrev_num_days_ago;
502                } else {
503                    resId = com.android.internal.R.plurals.num_days_ago;
504                }
505            } else {
506                if (abbrevRelative) {
507                    resId = com.android.internal.R.plurals.abbrev_in_num_days;
508                } else {
509                    resId = com.android.internal.R.plurals.in_num_days;
510                }
511            }
512        } else {
513            // We know that we won't be showing the time, so it is safe to pass
514            // in a null context.
515            return formatDateRange(null, time, time, flags);
516        }
517
518        String format = r.getQuantityString(resId, (int) count);
519        return String.format(format, count);
520    }
521
522    /**
523     * Return string describing the elapsed time since startTime formatted like
524     * "[relative time/date], [time]".
525     * <p>
526     * Example output strings for the US date format.
527     * <ul>
528     * <li>3 mins ago, 10:15 AM</li>
529     * <li>yesterday, 12:20 PM</li>
530     * <li>Dec 12, 4:12 AM</li>
531     * <li>11/14/2007, 8:20 AM</li>
532     * </ul>
533     *
534     * @param time some time in the past.
535     * @param minResolution the minimum elapsed time (in milliseconds) to report
536     *            when showing relative times. For example, a time 3 seconds in
537     *            the past will be reported as "0 minutes ago" if this is set to
538     *            {@link #MINUTE_IN_MILLIS}.
539     * @param transitionResolution the elapsed time (in milliseconds) at which
540     *            to stop reporting relative measurements. Elapsed times greater
541     *            than this resolution will default to normal date formatting.
542     *            For example, will transition from "6 days ago" to "Dec 12"
543     *            when using {@link #WEEK_IN_MILLIS}.
544     */
545    public static CharSequence getRelativeDateTimeString(Context c, long time, long minResolution,
546            long transitionResolution, int flags) {
547        Resources r = Resources.getSystem();
548
549        long now = System.currentTimeMillis();
550        long duration = Math.abs(now - time);
551
552        // getRelativeTimeSpanString() doesn't correctly format relative dates
553        // above a week or exact dates below a day, so clamp
554        // transitionResolution as needed.
555        if (transitionResolution > WEEK_IN_MILLIS) {
556            transitionResolution = WEEK_IN_MILLIS;
557        } else if (transitionResolution < DAY_IN_MILLIS) {
558            transitionResolution = DAY_IN_MILLIS;
559        }
560
561        CharSequence timeClause = formatDateRange(c, time, time, FORMAT_SHOW_TIME);
562
563        String result;
564        if (duration < transitionResolution) {
565            CharSequence relativeClause = getRelativeTimeSpanString(time, now, minResolution, flags);
566            result = r.getString(com.android.internal.R.string.relative_time, relativeClause, timeClause);
567        } else {
568            CharSequence dateClause = getRelativeTimeSpanString(c, time, false);
569            result = r.getString(com.android.internal.R.string.date_time, dateClause, timeClause);
570        }
571
572        return result;
573    }
574
575    /**
576     * Returns a string describing a day relative to the current day. For example if the day is
577     * today this function returns "Today", if the day was a week ago it returns "7 days ago", and
578     * if the day is in 2 weeks it returns "in 14 days".
579     *
580     * @param r the resources to get the strings from
581     * @param day the relative day to describe in UTC milliseconds
582     * @param today the current time in UTC milliseconds
583     * @return a formatting string
584     */
585    private static final String getRelativeDayString(Resources r, long day, long today) {
586        Time startTime = new Time();
587        startTime.set(day);
588        Time currentTime = new Time();
589        currentTime.set(today);
590
591        int startDay = Time.getJulianDay(day, startTime.gmtoff);
592        int currentDay = Time.getJulianDay(today, currentTime.gmtoff);
593
594        int days = Math.abs(currentDay - startDay);
595        boolean past = (today > day);
596
597        if (days == 1) {
598            if (past) {
599                return r.getString(com.android.internal.R.string.yesterday);
600            } else {
601                return r.getString(com.android.internal.R.string.tomorrow);
602            }
603        } else if (days == 0) {
604            return r.getString(com.android.internal.R.string.today);
605        }
606
607        int resId;
608        if (past) {
609            resId = com.android.internal.R.plurals.num_days_ago;
610        } else {
611            resId = com.android.internal.R.plurals.in_num_days;
612        }
613
614        String format = r.getQuantityString(resId, days);
615        return String.format(format, days);
616    }
617
618    private static void initFormatStrings() {
619        synchronized (sLock) {
620            Resources r = Resources.getSystem();
621            Configuration cfg = r.getConfiguration();
622            if (sLastConfig == null || !sLastConfig.equals(cfg)) {
623                sLastConfig = cfg;
624                sStatusTimeFormat = java.text.DateFormat.getTimeInstance(java.text.DateFormat.SHORT);
625                sElapsedFormatMMSS = r.getString(com.android.internal.R.string.elapsed_time_short_format_mm_ss);
626                sElapsedFormatHMMSS = r.getString(com.android.internal.R.string.elapsed_time_short_format_h_mm_ss);
627            }
628        }
629    }
630
631    /**
632     * Format a time so it appears like it would in the status bar clock.
633     * @deprecated use {@link #DateFormat.getTimeFormat(Context)} instead.
634     * @hide
635     */
636    public static final CharSequence timeString(long millis) {
637        initFormatStrings();
638        return sStatusTimeFormat.format(millis);
639    }
640
641    /**
642     * Formats an elapsed time in the form "MM:SS" or "H:MM:SS"
643     * for display on the call-in-progress screen.
644     * @param elapsedSeconds the elapsed time in seconds.
645     */
646    public static String formatElapsedTime(long elapsedSeconds) {
647        return formatElapsedTime(null, elapsedSeconds);
648    }
649
650    /**
651     * Formats an elapsed time in the form "MM:SS" or "H:MM:SS"
652     * for display on the call-in-progress screen.
653     *
654     * @param recycle {@link StringBuilder} to recycle, if possible
655     * @param elapsedSeconds the elapsed time in seconds.
656     */
657    public static String formatElapsedTime(StringBuilder recycle, long elapsedSeconds) {
658        initFormatStrings();
659
660        long hours = 0;
661        long minutes = 0;
662        long seconds = 0;
663
664        if (elapsedSeconds >= 3600) {
665            hours = elapsedSeconds / 3600;
666            elapsedSeconds -= hours * 3600;
667        }
668        if (elapsedSeconds >= 60) {
669            minutes = elapsedSeconds / 60;
670            elapsedSeconds -= minutes * 60;
671        }
672        seconds = elapsedSeconds;
673
674        String result;
675        if (hours > 0) {
676            return formatElapsedTime(recycle, sElapsedFormatHMMSS, hours, minutes, seconds);
677        } else {
678            return formatElapsedTime(recycle, sElapsedFormatMMSS, minutes, seconds);
679        }
680    }
681
682    /**
683     * Fast formatting of h:mm:ss
684     */
685    private static String formatElapsedTime(StringBuilder recycle, String format, long hours,
686            long minutes, long seconds) {
687        if (FAST_FORMAT_HMMSS.equals(format)) {
688            StringBuilder sb = recycle;
689            if (sb == null) {
690                sb = new StringBuilder(8);
691            } else {
692                sb.setLength(0);
693            }
694            sb.append(hours);
695            sb.append(TIME_SEPARATOR);
696            if (minutes < 10) {
697                sb.append(TIME_PADDING);
698            } else {
699                sb.append(toDigitChar(minutes / 10));
700            }
701            sb.append(toDigitChar(minutes % 10));
702            sb.append(TIME_SEPARATOR);
703            if (seconds < 10) {
704                sb.append(TIME_PADDING);
705            } else {
706                sb.append(toDigitChar(seconds / 10));
707            }
708            sb.append(toDigitChar(seconds % 10));
709            return sb.toString();
710        } else {
711            return String.format(format, hours, minutes, seconds);
712        }
713    }
714
715    /**
716     * Fast formatting of m:ss
717     */
718    private static String formatElapsedTime(StringBuilder recycle, String format, long minutes,
719            long seconds) {
720        if (FAST_FORMAT_MMSS.equals(format)) {
721            StringBuilder sb = recycle;
722            if (sb == null) {
723                sb = new StringBuilder(8);
724            } else {
725                sb.setLength(0);
726            }
727            if (minutes < 10) {
728                sb.append(TIME_PADDING);
729            } else {
730                sb.append(toDigitChar(minutes / 10));
731            }
732            sb.append(toDigitChar(minutes % 10));
733            sb.append(TIME_SEPARATOR);
734            if (seconds < 10) {
735                sb.append(TIME_PADDING);
736            } else {
737                sb.append(toDigitChar(seconds / 10));
738            }
739            sb.append(toDigitChar(seconds % 10));
740            return sb.toString();
741        } else {
742            return String.format(format, minutes, seconds);
743        }
744    }
745
746    private static char toDigitChar(long digit) {
747        return (char) (digit + '0');
748    }
749
750    /**
751     * Format a date / time such that if the then is on the same day as now, it shows
752     * just the time and if it's a different day, it shows just the date.
753     *
754     * <p>The parameters dateFormat and timeFormat should each be one of
755     * {@link java.text.DateFormat#DEFAULT},
756     * {@link java.text.DateFormat#FULL},
757     * {@link java.text.DateFormat#LONG},
758     * {@link java.text.DateFormat#MEDIUM}
759     * or
760     * {@link java.text.DateFormat#SHORT}
761     *
762     * @param then the date to format
763     * @param now the base time
764     * @param dateStyle how to format the date portion.
765     * @param timeStyle how to format the time portion.
766     */
767    public static final CharSequence formatSameDayTime(long then, long now,
768            int dateStyle, int timeStyle) {
769        Calendar thenCal = new GregorianCalendar();
770        thenCal.setTimeInMillis(then);
771        Date thenDate = thenCal.getTime();
772        Calendar nowCal = new GregorianCalendar();
773        nowCal.setTimeInMillis(now);
774
775        java.text.DateFormat f;
776
777        if (thenCal.get(Calendar.YEAR) == nowCal.get(Calendar.YEAR)
778                && thenCal.get(Calendar.MONTH) == nowCal.get(Calendar.MONTH)
779                && thenCal.get(Calendar.DAY_OF_MONTH) == nowCal.get(Calendar.DAY_OF_MONTH)) {
780            f = java.text.DateFormat.getTimeInstance(timeStyle);
781        } else {
782            f = java.text.DateFormat.getDateInstance(dateStyle);
783        }
784        return f.format(thenDate);
785    }
786
787    /**
788     * @hide
789     * @deprecated use {@link android.text.format.Time}
790     */
791    public static Calendar newCalendar(boolean zulu)
792    {
793        if (zulu)
794            return Calendar.getInstance(TimeZone.getTimeZone("GMT"));
795
796        return Calendar.getInstance();
797    }
798
799    /**
800     * @return true if the supplied when is today else false
801     */
802    public static boolean isToday(long when) {
803        Time time = new Time();
804        time.set(when);
805
806        int thenYear = time.year;
807        int thenMonth = time.month;
808        int thenMonthDay = time.monthDay;
809
810        time.set(System.currentTimeMillis());
811        return (thenYear == time.year)
812                && (thenMonth == time.month)
813                && (thenMonthDay == time.monthDay);
814    }
815
816    /**
817     * @hide
818     * @deprecated use {@link android.text.format.Time}
819     */
820    private static final int ctoi(String str, int index)
821                                                throws DateException
822    {
823        char c = str.charAt(index);
824        if (c >= '0' && c <= '9') {
825            return (int)(c - '0');
826        }
827        throw new DateException("Expected numeric character.  Got '" +
828                                            c + "'");
829    }
830
831    /**
832     * @hide
833     * @deprecated use {@link android.text.format.Time}
834     */
835    private static final int check(int lowerBound, int upperBound, int value)
836                                                throws DateException
837    {
838        if (value >= lowerBound && value <= upperBound) {
839            return value;
840        }
841        throw new DateException("field out of bounds.  max=" + upperBound
842                                        + " value=" + value);
843    }
844
845    /**
846     * @hide
847     * @deprecated use {@link android.text.format.Time}
848     * Return true if this date string is local time
849     */
850    public static boolean isUTC(String s)
851    {
852        if (s.length() == 16 && s.charAt(15) == 'Z') {
853            return true;
854        }
855        if (s.length() == 9 && s.charAt(8) == 'Z') {
856            // XXX not sure if this case possible/valid
857            return true;
858        }
859        return false;
860    }
861
862
863    // note that month in Calendar is 0 based and in all other human
864    // representations, it's 1 based.
865    // Returns if the Z was present, meaning that the time is in UTC
866    /**
867     * @hide
868     * @deprecated use {@link android.text.format.Time}
869     */
870    public static boolean parseDateTime(String str, Calendar cal)
871                                                throws DateException
872    {
873        int len = str.length();
874        boolean dateTime = (len == 15 || len == 16) && str.charAt(8) == 'T';
875        boolean justDate = len == 8;
876        if (dateTime || justDate) {
877            cal.clear();
878            cal.set(Calendar.YEAR,
879                            ctoi(str, 0)*1000 + ctoi(str, 1)*100
880                            + ctoi(str, 2)*10 + ctoi(str, 3));
881            cal.set(Calendar.MONTH,
882                            check(0, 11, ctoi(str, 4)*10 + ctoi(str, 5) - 1));
883            cal.set(Calendar.DAY_OF_MONTH,
884                            check(1, 31, ctoi(str, 6)*10 + ctoi(str, 7)));
885            if (dateTime) {
886                cal.set(Calendar.HOUR_OF_DAY,
887                            check(0, 23, ctoi(str, 9)*10 + ctoi(str, 10)));
888                cal.set(Calendar.MINUTE,
889                            check(0, 59, ctoi(str, 11)*10 + ctoi(str, 12)));
890                cal.set(Calendar.SECOND,
891                            check(0, 59, ctoi(str, 13)*10 + ctoi(str, 14)));
892            }
893            if (justDate) {
894                cal.set(Calendar.HOUR_OF_DAY, 0);
895                cal.set(Calendar.MINUTE, 0);
896                cal.set(Calendar.SECOND, 0);
897                return true;
898            }
899            if (len == 15) {
900                return false;
901            }
902            if (str.charAt(15) == 'Z') {
903                return true;
904            }
905        }
906        throw new DateException("Invalid time (expected "
907                                + "YYYYMMDDThhmmssZ? got '" + str + "').");
908    }
909
910    /**
911     * Given a timezone string which can be null, and a dateTime string,
912     * set that time into a calendar.
913     * @hide
914     * @deprecated use {@link android.text.format.Time}
915     */
916    public static void parseDateTime(String tz, String dateTime, Calendar out)
917                                                throws DateException
918    {
919        TimeZone timezone;
920        if (DateUtils.isUTC(dateTime)) {
921            timezone = TimeZone.getTimeZone("UTC");
922        }
923        else if (tz == null) {
924            timezone = TimeZone.getDefault();
925        }
926        else {
927            timezone = TimeZone.getTimeZone(tz);
928        }
929
930        Calendar local = new GregorianCalendar(timezone);
931        DateUtils.parseDateTime(dateTime, local);
932
933        out.setTimeInMillis(local.getTimeInMillis());
934    }
935
936
937    /**
938     * Return a string containing the date and time in RFC2445 format.
939     * Ensures that the time is written in UTC.  The Calendar class doesn't
940     * really help out with this, so this is slower than it ought to be.
941     *
942     * @param cal the date and time to write
943     * @hide
944     * @deprecated use {@link android.text.format.Time}
945     */
946    public static String writeDateTime(Calendar cal)
947    {
948        TimeZone tz = TimeZone.getTimeZone("GMT");
949        GregorianCalendar c = new GregorianCalendar(tz);
950        c.setTimeInMillis(cal.getTimeInMillis());
951        return writeDateTime(c, true);
952    }
953
954    /**
955     * Return a string containing the date and time in RFC2445 format.
956     *
957     * @param cal the date and time to write
958     * @param zulu If the calendar is in UTC, pass true, and a Z will
959     * be written at the end as per RFC2445.  Otherwise, the time is
960     * considered in localtime.
961     * @hide
962     * @deprecated use {@link android.text.format.Time}
963     */
964    public static String writeDateTime(Calendar cal, boolean zulu)
965    {
966        StringBuilder sb = new StringBuilder();
967        sb.ensureCapacity(16);
968        if (zulu) {
969            sb.setLength(16);
970            sb.setCharAt(15, 'Z');
971        } else {
972            sb.setLength(15);
973        }
974        return writeDateTime(cal, sb);
975    }
976
977    /**
978     * Return a string containing the date and time in RFC2445 format.
979     *
980     * @param cal the date and time to write
981     * @param sb a StringBuilder to use.  It is assumed that setLength
982     *           has already been called on sb to the appropriate length
983     *           which is sb.setLength(zulu ? 16 : 15)
984     * @hide
985     * @deprecated use {@link android.text.format.Time}
986     */
987    public static String writeDateTime(Calendar cal, StringBuilder sb)
988    {
989        int n;
990
991        n = cal.get(Calendar.YEAR);
992        sb.setCharAt(3, (char)('0'+n%10));
993        n /= 10;
994        sb.setCharAt(2, (char)('0'+n%10));
995        n /= 10;
996        sb.setCharAt(1, (char)('0'+n%10));
997        n /= 10;
998        sb.setCharAt(0, (char)('0'+n%10));
999
1000        n = cal.get(Calendar.MONTH) + 1;
1001        sb.setCharAt(5, (char)('0'+n%10));
1002        n /= 10;
1003        sb.setCharAt(4, (char)('0'+n%10));
1004
1005        n = cal.get(Calendar.DAY_OF_MONTH);
1006        sb.setCharAt(7, (char)('0'+n%10));
1007        n /= 10;
1008        sb.setCharAt(6, (char)('0'+n%10));
1009
1010        sb.setCharAt(8, 'T');
1011
1012        n = cal.get(Calendar.HOUR_OF_DAY);
1013        sb.setCharAt(10, (char)('0'+n%10));
1014        n /= 10;
1015        sb.setCharAt(9, (char)('0'+n%10));
1016
1017        n = cal.get(Calendar.MINUTE);
1018        sb.setCharAt(12, (char)('0'+n%10));
1019        n /= 10;
1020        sb.setCharAt(11, (char)('0'+n%10));
1021
1022        n = cal.get(Calendar.SECOND);
1023        sb.setCharAt(14, (char)('0'+n%10));
1024        n /= 10;
1025        sb.setCharAt(13, (char)('0'+n%10));
1026
1027        return sb.toString();
1028    }
1029
1030    /**
1031     * @hide
1032     * @deprecated use {@link android.text.format.Time}
1033     */
1034    public static void assign(Calendar lval, Calendar rval)
1035    {
1036        // there should be a faster way.
1037        lval.clear();
1038        lval.setTimeInMillis(rval.getTimeInMillis());
1039    }
1040
1041    /**
1042     * Formats a date or a time range according to the local conventions.
1043     *
1044     * <p>
1045     * Example output strings (date formats in these examples are shown using
1046     * the US date format convention but that may change depending on the
1047     * local settings):
1048     * <ul>
1049     *   <li>10:15am</li>
1050     *   <li>3:00pm - 4:00pm</li>
1051     *   <li>3pm - 4pm</li>
1052     *   <li>3PM - 4PM</li>
1053     *   <li>08:00 - 17:00</li>
1054     *   <li>Oct 9</li>
1055     *   <li>Tue, Oct 9</li>
1056     *   <li>October 9, 2007</li>
1057     *   <li>Oct 9 - 10</li>
1058     *   <li>Oct 9 - 10, 2007</li>
1059     *   <li>Oct 28 - Nov 3, 2007</li>
1060     *   <li>Dec 31, 2007 - Jan 1, 2008</li>
1061     *   <li>Oct 9, 8:00am - Oct 10, 5:00pm</li>
1062     *   <li>12/31/2007 - 01/01/2008</li>
1063     * </ul>
1064     *
1065     * <p>
1066     * The flags argument is a bitmask of options from the following list:
1067     *
1068     * <ul>
1069     *   <li>FORMAT_SHOW_TIME</li>
1070     *   <li>FORMAT_SHOW_WEEKDAY</li>
1071     *   <li>FORMAT_SHOW_YEAR</li>
1072     *   <li>FORMAT_NO_YEAR</li>
1073     *   <li>FORMAT_SHOW_DATE</li>
1074     *   <li>FORMAT_NO_MONTH_DAY</li>
1075     *   <li>FORMAT_12HOUR</li>
1076     *   <li>FORMAT_24HOUR</li>
1077     *   <li>FORMAT_CAP_AMPM</li>
1078     *   <li>FORMAT_NO_NOON</li>
1079     *   <li>FORMAT_CAP_NOON</li>
1080     *   <li>FORMAT_NO_MIDNIGHT</li>
1081     *   <li>FORMAT_CAP_MIDNIGHT</li>
1082     *   <li>FORMAT_UTC</li>
1083     *   <li>FORMAT_ABBREV_TIME</li>
1084     *   <li>FORMAT_ABBREV_WEEKDAY</li>
1085     *   <li>FORMAT_ABBREV_MONTH</li>
1086     *   <li>FORMAT_ABBREV_ALL</li>
1087     *   <li>FORMAT_NUMERIC_DATE</li>
1088     * </ul>
1089     *
1090     * <p>
1091     * If FORMAT_SHOW_TIME is set, the time is shown as part of the date range.
1092     * If the start and end time are the same, then just the start time is
1093     * shown.
1094     *
1095     * <p>
1096     * If FORMAT_SHOW_WEEKDAY is set, then the weekday is shown.
1097     *
1098     * <p>
1099     * If FORMAT_SHOW_YEAR is set, then the year is always shown.
1100     * If FORMAT_NO_YEAR is set, then the year is not shown.
1101     * If neither FORMAT_SHOW_YEAR nor FORMAT_NO_YEAR are set, then the year
1102     * is shown only if it is different from the current year, or if the start
1103     * and end dates fall on different years.  If both are set,
1104     * FORMAT_SHOW_YEAR takes precedence.
1105     *
1106     * <p>
1107     * Normally the date is shown unless the start and end day are the same.
1108     * If FORMAT_SHOW_DATE is set, then the date is always shown, even for
1109     * same day ranges.
1110     *
1111     * <p>
1112     * If FORMAT_NO_MONTH_DAY is set, then if the date is shown, just the
1113     * month name will be shown, not the day of the month.  For example,
1114     * "January, 2008" instead of "January 6 - 12, 2008".
1115     *
1116     * <p>
1117     * If FORMAT_CAP_AMPM is set and 12-hour time is used, then the "AM"
1118     * and "PM" are capitalized.  You should not use this flag
1119     * because in some locales these terms cannot be capitalized, and in
1120     * many others it doesn't make sense to do so even though it is possible.
1121     *
1122     * <p>
1123     * If FORMAT_NO_NOON is set and 12-hour time is used, then "12pm" is
1124     * shown instead of "noon".
1125     *
1126     * <p>
1127     * If FORMAT_CAP_NOON is set and 12-hour time is used, then "Noon" is
1128     * shown instead of "noon".  You should probably not use this flag
1129     * because in many locales it will not make sense to capitalize
1130     * the term.
1131     *
1132     * <p>
1133     * If FORMAT_NO_MIDNIGHT is set and 12-hour time is used, then "12am" is
1134     * shown instead of "midnight".
1135     *
1136     * <p>
1137     * If FORMAT_CAP_MIDNIGHT is set and 12-hour time is used, then "Midnight"
1138     * is shown instead of "midnight".  You should probably not use this
1139     * flag because in many locales it will not make sense to capitalize
1140     * the term.
1141     *
1142     * <p>
1143     * If FORMAT_12HOUR is set and the time is shown, then the time is
1144     * shown in the 12-hour time format. You should not normally set this.
1145     * Instead, let the time format be chosen automatically according to the
1146     * system settings. If both FORMAT_12HOUR and FORMAT_24HOUR are set, then
1147     * FORMAT_24HOUR takes precedence.
1148     *
1149     * <p>
1150     * If FORMAT_24HOUR is set and the time is shown, then the time is
1151     * shown in the 24-hour time format. You should not normally set this.
1152     * Instead, let the time format be chosen automatically according to the
1153     * system settings. If both FORMAT_12HOUR and FORMAT_24HOUR are set, then
1154     * FORMAT_24HOUR takes precedence.
1155     *
1156     * <p>
1157     * If FORMAT_UTC is set, then the UTC timezone is used for the start
1158     * and end milliseconds.
1159     *
1160     * <p>
1161     * If FORMAT_ABBREV_TIME is set and 12-hour time format is used, then the
1162     * start and end times (if shown) are abbreviated by not showing the minutes
1163     * if they are zero.  For example, instead of "3:00pm" the time would be
1164     * abbreviated to "3pm".
1165     *
1166     * <p>
1167     * If FORMAT_ABBREV_WEEKDAY is set, then the weekday (if shown) is
1168     * abbreviated to a 3-letter string.
1169     *
1170     * <p>
1171     * If FORMAT_ABBREV_MONTH is set, then the month (if shown) is abbreviated
1172     * to a 3-letter string.
1173     *
1174     * <p>
1175     * If FORMAT_ABBREV_ALL is set, then the weekday and the month (if shown)
1176     * are abbreviated to 3-letter strings.
1177     *
1178     * <p>
1179     * If FORMAT_NUMERIC_DATE is set, then the date is shown in numeric format
1180     * instead of using the name of the month.  For example, "12/31/2008"
1181     * instead of "December 31, 2008".
1182     *
1183     * @param context the context is required only if the time is shown
1184     * @param startMillis the start time in UTC milliseconds
1185     * @param endMillis the end time in UTC milliseconds
1186     * @param flags a bit mask of options
1187     *
1188     * @return a string containing the formatted date/time range.
1189     */
1190    public static String formatDateRange(Context context, long startMillis,
1191                long endMillis, int flags) {
1192        Resources res = Resources.getSystem();
1193        boolean showTime = (flags & FORMAT_SHOW_TIME) != 0;
1194        boolean showWeekDay = (flags & FORMAT_SHOW_WEEKDAY) != 0;
1195        boolean showYear = (flags & FORMAT_SHOW_YEAR) != 0;
1196        boolean noYear = (flags & FORMAT_NO_YEAR) != 0;
1197        boolean useUTC = (flags & FORMAT_UTC) != 0;
1198        boolean abbrevWeekDay = (flags & (FORMAT_ABBREV_WEEKDAY | FORMAT_ABBREV_ALL)) != 0;
1199        boolean abbrevMonth = (flags & (FORMAT_ABBREV_MONTH | FORMAT_ABBREV_ALL)) != 0;
1200        boolean noMonthDay = (flags & FORMAT_NO_MONTH_DAY) != 0;
1201        boolean numericDate = (flags & FORMAT_NUMERIC_DATE) != 0;
1202
1203        // If we're getting called with a single instant in time (from
1204        // e.g. formatDateTime(), below), then we can skip a lot of
1205        // computation below that'd otherwise be thrown out.
1206        boolean isInstant = (startMillis == endMillis);
1207
1208        Time startDate = useUTC ? new Time(Time.TIMEZONE_UTC) : new Time();
1209        startDate.set(startMillis);
1210
1211        Time endDate;
1212        int dayDistance;
1213        if (isInstant) {
1214            endDate = startDate;
1215            dayDistance = 0;
1216        } else {
1217            endDate = useUTC ? new Time(Time.TIMEZONE_UTC) : new Time();
1218            endDate.set(endMillis);
1219            int startJulianDay = Time.getJulianDay(startMillis, startDate.gmtoff);
1220            int endJulianDay = Time.getJulianDay(endMillis, endDate.gmtoff);
1221            dayDistance = endJulianDay - startJulianDay;
1222        }
1223
1224        // If the end date ends at 12am at the beginning of a day,
1225        // then modify it to make it look like it ends at midnight on
1226        // the previous day.  This will allow us to display "8pm - midnight",
1227        // for example, instead of "Nov 10, 8pm - Nov 11, 12am". But we only do
1228        // this if it is midnight of the same day as the start date because
1229        // for multiple-day events, an end time of "midnight on Nov 11" is
1230        // ambiguous and confusing (is that midnight the start of Nov 11, or
1231        // the end of Nov 11?).
1232        // If we are not showing the time then also adjust the end date
1233        // for multiple-day events.  This is to allow us to display, for
1234        // example, "Nov 10 -11" for an event with a start date of Nov 10
1235        // and an end date of Nov 12 at 00:00.
1236        // If the start and end time are the same, then skip this and don't
1237        // adjust the date.
1238        if (!isInstant
1239            && (endDate.hour | endDate.minute | endDate.second) == 0
1240            && (!showTime || dayDistance <= 1)) {
1241            endDate.monthDay -= 1;
1242            endDate.normalize(true /* ignore isDst */);
1243        }
1244
1245        int startDay = startDate.monthDay;
1246        int startMonthNum = startDate.month;
1247        int startYear = startDate.year;
1248
1249        int endDay = endDate.monthDay;
1250        int endMonthNum = endDate.month;
1251        int endYear = endDate.year;
1252
1253        String startWeekDayString = "";
1254        String endWeekDayString = "";
1255        if (showWeekDay) {
1256            String weekDayFormat = "";
1257            if (abbrevWeekDay) {
1258                weekDayFormat = ABBREV_WEEKDAY_FORMAT;
1259            } else {
1260                weekDayFormat = WEEKDAY_FORMAT;
1261            }
1262            startWeekDayString = startDate.format(weekDayFormat);
1263            endWeekDayString = isInstant ? startWeekDayString : endDate.format(weekDayFormat);
1264        }
1265
1266        String startTimeString = "";
1267        String endTimeString = "";
1268        if (showTime) {
1269            String startTimeFormat = "";
1270            String endTimeFormat = "";
1271            boolean force24Hour = (flags & FORMAT_24HOUR) != 0;
1272            boolean force12Hour = (flags & FORMAT_12HOUR) != 0;
1273            boolean use24Hour;
1274            if (force24Hour) {
1275                use24Hour = true;
1276            } else if (force12Hour) {
1277                use24Hour = false;
1278            } else {
1279                use24Hour = DateFormat.is24HourFormat(context);
1280            }
1281            if (use24Hour) {
1282                startTimeFormat = endTimeFormat =
1283                    res.getString(com.android.internal.R.string.hour_minute_24);
1284            } else {
1285                boolean abbrevTime = (flags & (FORMAT_ABBREV_TIME | FORMAT_ABBREV_ALL)) != 0;
1286                boolean capAMPM = (flags & FORMAT_CAP_AMPM) != 0;
1287                boolean noNoon = (flags & FORMAT_NO_NOON) != 0;
1288                boolean capNoon = (flags & FORMAT_CAP_NOON) != 0;
1289                boolean noMidnight = (flags & FORMAT_NO_MIDNIGHT) != 0;
1290                boolean capMidnight = (flags & FORMAT_CAP_MIDNIGHT) != 0;
1291
1292                boolean startOnTheHour = startDate.minute == 0 && startDate.second == 0;
1293                boolean endOnTheHour = endDate.minute == 0 && endDate.second == 0;
1294                if (abbrevTime && startOnTheHour) {
1295                    if (capAMPM) {
1296                        startTimeFormat = res.getString(com.android.internal.R.string.hour_cap_ampm);
1297                    } else {
1298                        startTimeFormat = res.getString(com.android.internal.R.string.hour_ampm);
1299                    }
1300                } else {
1301                    if (capAMPM) {
1302                        startTimeFormat = res.getString(com.android.internal.R.string.hour_minute_cap_ampm);
1303                    } else {
1304                        startTimeFormat = res.getString(com.android.internal.R.string.hour_minute_ampm);
1305                    }
1306                }
1307
1308                // Don't waste time on setting endTimeFormat when
1309                // we're dealing with an instant, where we'll never
1310                // need the end point.  (It's the same as the start
1311                // point)
1312                if (!isInstant) {
1313                    if (abbrevTime && endOnTheHour) {
1314                        if (capAMPM) {
1315                            endTimeFormat = res.getString(com.android.internal.R.string.hour_cap_ampm);
1316                        } else {
1317                            endTimeFormat = res.getString(com.android.internal.R.string.hour_ampm);
1318                        }
1319                    } else {
1320                        if (capAMPM) {
1321                            endTimeFormat = res.getString(com.android.internal.R.string.hour_minute_cap_ampm);
1322                        } else {
1323                            endTimeFormat = res.getString(com.android.internal.R.string.hour_minute_ampm);
1324                        }
1325                    }
1326
1327                    if (endDate.hour == 12 && endOnTheHour && !noNoon) {
1328                        if (capNoon) {
1329                            endTimeFormat = res.getString(com.android.internal.R.string.Noon);
1330                        } else {
1331                            endTimeFormat = res.getString(com.android.internal.R.string.noon);
1332                        }
1333                    } else if (endDate.hour == 0 && endOnTheHour && !noMidnight) {
1334                        if (capMidnight) {
1335                            endTimeFormat = res.getString(com.android.internal.R.string.Midnight);
1336                        } else {
1337                            endTimeFormat = res.getString(com.android.internal.R.string.midnight);
1338                        }
1339                    }
1340                }
1341
1342                if (startDate.hour == 12 && startOnTheHour && !noNoon) {
1343                    if (capNoon) {
1344                        startTimeFormat = res.getString(com.android.internal.R.string.Noon);
1345                    } else {
1346                        startTimeFormat = res.getString(com.android.internal.R.string.noon);
1347                    }
1348                    // Don't show the start time starting at midnight.  Show
1349                    // 12am instead.
1350                }
1351            }
1352
1353            startTimeString = startDate.format(startTimeFormat);
1354            endTimeString = isInstant ? startTimeString : endDate.format(endTimeFormat);
1355        }
1356
1357        // Show the year if the user specified FORMAT_SHOW_YEAR or if
1358        // the starting and end years are different from each other
1359        // or from the current year.  But don't show the year if the
1360        // user specified FORMAT_NO_YEAR.
1361        if (showYear) {
1362            // No code... just a comment for clarity.  Keep showYear
1363            // on, as they enabled it with FORMAT_SHOW_YEAR.  This
1364            // takes precedence over them setting FORMAT_NO_YEAR.
1365        } else if (noYear) {
1366            // They explicitly didn't want a year.
1367            showYear = false;
1368        } else if (startYear != endYear) {
1369            showYear = true;
1370        } else {
1371            // Show the year if it's not equal to the current year.
1372            Time currentTime = new Time();
1373            currentTime.setToNow();
1374            showYear = startYear != currentTime.year;
1375        }
1376
1377        String defaultDateFormat, fullFormat, dateRange;
1378        if (numericDate) {
1379            defaultDateFormat = res.getString(com.android.internal.R.string.numeric_date);
1380        } else if (showYear) {
1381            if (abbrevMonth) {
1382                if (noMonthDay) {
1383                    defaultDateFormat = res.getString(com.android.internal.R.string.abbrev_month_year);
1384                } else {
1385                    defaultDateFormat = res.getString(com.android.internal.R.string.abbrev_month_day_year);
1386                }
1387            } else {
1388                if (noMonthDay) {
1389                    defaultDateFormat = res.getString(com.android.internal.R.string.month_year);
1390                } else {
1391                    defaultDateFormat = res.getString(com.android.internal.R.string.month_day_year);
1392                }
1393            }
1394        } else {
1395            if (abbrevMonth) {
1396                if (noMonthDay) {
1397                    defaultDateFormat = res.getString(com.android.internal.R.string.abbrev_month);
1398                } else {
1399                    defaultDateFormat = res.getString(com.android.internal.R.string.abbrev_month_day);
1400                }
1401            } else {
1402                if (noMonthDay) {
1403                    defaultDateFormat = res.getString(com.android.internal.R.string.month);
1404                } else {
1405                    defaultDateFormat = res.getString(com.android.internal.R.string.month_day);
1406                }
1407            }
1408        }
1409
1410        if (showWeekDay) {
1411            if (showTime) {
1412                fullFormat = res.getString(com.android.internal.R.string.wday1_date1_time1_wday2_date2_time2);
1413            } else {
1414                fullFormat = res.getString(com.android.internal.R.string.wday1_date1_wday2_date2);
1415            }
1416        } else {
1417            if (showTime) {
1418                fullFormat = res.getString(com.android.internal.R.string.date1_time1_date2_time2);
1419            } else {
1420                fullFormat = res.getString(com.android.internal.R.string.date1_date2);
1421            }
1422        }
1423
1424        if (noMonthDay && startMonthNum == endMonthNum) {
1425            // Example: "January, 2008"
1426            String startDateString = startDate.format(defaultDateFormat);
1427            return startDateString;
1428        }
1429
1430        if (startYear != endYear || noMonthDay) {
1431            // Different year or we are not showing the month day number.
1432            // Example: "December 31, 2007 - January 1, 2008"
1433            // Or: "January - February, 2008"
1434            String startDateString = startDate.format(defaultDateFormat);
1435            String endDateString = endDate.format(defaultDateFormat);
1436
1437            // The values that are used in a fullFormat string are specified
1438            // by position.
1439            dateRange = String.format(fullFormat,
1440                    startWeekDayString, startDateString, startTimeString,
1441                    endWeekDayString, endDateString, endTimeString);
1442            return dateRange;
1443        }
1444
1445        // Get the month, day, and year strings for the start and end dates
1446        String monthFormat;
1447        if (numericDate) {
1448            monthFormat = NUMERIC_MONTH_FORMAT;
1449        } else if (abbrevMonth) {
1450            monthFormat =
1451                res.getString(com.android.internal.R.string.short_format_month);
1452        } else {
1453            monthFormat = MONTH_FORMAT;
1454        }
1455        String startMonthString = startDate.format(monthFormat);
1456        String startMonthDayString = startDate.format(MONTH_DAY_FORMAT);
1457        String startYearString = startDate.format(YEAR_FORMAT);
1458
1459        String endMonthString = isInstant ? null : endDate.format(monthFormat);
1460        String endMonthDayString = isInstant ? null : endDate.format(MONTH_DAY_FORMAT);
1461        String endYearString = isInstant ? null : endDate.format(YEAR_FORMAT);
1462
1463        if (startMonthNum != endMonthNum) {
1464            // Same year, different month.
1465            // Example: "October 28 - November 3"
1466            // or: "Wed, Oct 31 - Sat, Nov 3, 2007"
1467            // or: "Oct 31, 8am - Sat, Nov 3, 2007, 5pm"
1468
1469            int index = 0;
1470            if (showWeekDay) index = 1;
1471            if (showYear) index += 2;
1472            if (showTime) index += 4;
1473            if (numericDate) index += 8;
1474            int resId = sameYearTable[index];
1475            fullFormat = res.getString(resId);
1476
1477            // The values that are used in a fullFormat string are specified
1478            // by position.
1479            dateRange = String.format(fullFormat,
1480                    startWeekDayString, startMonthString, startMonthDayString,
1481                    startYearString, startTimeString,
1482                    endWeekDayString, endMonthString, endMonthDayString,
1483                    endYearString, endTimeString);
1484            return dateRange;
1485        }
1486
1487        if (startDay != endDay) {
1488            // Same month, different day.
1489            int index = 0;
1490            if (showWeekDay) index = 1;
1491            if (showYear) index += 2;
1492            if (showTime) index += 4;
1493            if (numericDate) index += 8;
1494            int resId = sameMonthTable[index];
1495            fullFormat = res.getString(resId);
1496
1497            // The values that are used in a fullFormat string are specified
1498            // by position.
1499            dateRange = String.format(fullFormat,
1500                    startWeekDayString, startMonthString, startMonthDayString,
1501                    startYearString, startTimeString,
1502                    endWeekDayString, endMonthString, endMonthDayString,
1503                    endYearString, endTimeString);
1504            return dateRange;
1505        }
1506
1507        // Same start and end day
1508        boolean showDate = (flags & FORMAT_SHOW_DATE) != 0;
1509
1510        // If nothing was specified, then show the date.
1511        if (!showTime && !showDate && !showWeekDay) showDate = true;
1512
1513        // Compute the time string (example: "10:00 - 11:00 am")
1514        String timeString = "";
1515        if (showTime) {
1516            // If the start and end time are the same, then just show the
1517            // start time.
1518            if (isInstant) {
1519                // Same start and end time.
1520                // Example: "10:15 AM"
1521                timeString = startTimeString;
1522            } else {
1523                // Example: "10:00 - 11:00 am"
1524                String timeFormat = res.getString(com.android.internal.R.string.time1_time2);
1525                timeString = String.format(timeFormat, startTimeString, endTimeString);
1526            }
1527        }
1528
1529        // Figure out which full format to use.
1530        fullFormat = "";
1531        String dateString = "";
1532        if (showDate) {
1533            dateString = startDate.format(defaultDateFormat);
1534            if (showWeekDay) {
1535                if (showTime) {
1536                    // Example: "10:00 - 11:00 am, Tue, Oct 9"
1537                    fullFormat = res.getString(com.android.internal.R.string.time_wday_date);
1538                } else {
1539                    // Example: "Tue, Oct 9"
1540                    fullFormat = res.getString(com.android.internal.R.string.wday_date);
1541                }
1542            } else {
1543                if (showTime) {
1544                    // Example: "10:00 - 11:00 am, Oct 9"
1545                    fullFormat = res.getString(com.android.internal.R.string.time_date);
1546                } else {
1547                    // Example: "Oct 9"
1548                    return dateString;
1549                }
1550            }
1551        } else if (showWeekDay) {
1552            if (showTime) {
1553                // Example: "10:00 - 11:00 am, Tue"
1554                fullFormat = res.getString(com.android.internal.R.string.time_wday);
1555            } else {
1556                // Example: "Tue"
1557                return startWeekDayString;
1558            }
1559        } else if (showTime) {
1560            return timeString;
1561        }
1562
1563        // The values that are used in a fullFormat string are specified
1564        // by position.
1565        dateRange = String.format(fullFormat, timeString, startWeekDayString, dateString);
1566        return dateRange;
1567    }
1568
1569    /**
1570     * Formats a date or a time according to the local conventions. There are
1571     * lots of options that allow the caller to control, for example, if the
1572     * time is shown, if the day of the week is shown, if the month name is
1573     * abbreviated, if noon is shown instead of 12pm, and so on. For the
1574     * complete list of options, see the documentation for
1575     * {@link #formatDateRange}.
1576     * <p>
1577     * Example output strings (date formats in these examples are shown using
1578     * the US date format convention but that may change depending on the
1579     * local settings):
1580     * <ul>
1581     *   <li>10:15am</li>
1582     *   <li>3:00pm</li>
1583     *   <li>3pm</li>
1584     *   <li>3PM</li>
1585     *   <li>08:00</li>
1586     *   <li>17:00</li>
1587     *   <li>noon</li>
1588     *   <li>Noon</li>
1589     *   <li>midnight</li>
1590     *   <li>Midnight</li>
1591     *   <li>Oct 31</li>
1592     *   <li>Oct 31, 2007</li>
1593     *   <li>October 31, 2007</li>
1594     *   <li>10am, Oct 31</li>
1595     *   <li>17:00, Oct 31</li>
1596     *   <li>Wed</li>
1597     *   <li>Wednesday</li>
1598     *   <li>10am, Wed, Oct 31</li>
1599     *   <li>Wed, Oct 31</li>
1600     *   <li>Wednesday, Oct 31</li>
1601     *   <li>Wed, Oct 31, 2007</li>
1602     *   <li>Wed, October 31</li>
1603     *   <li>10/31/2007</li>
1604     * </ul>
1605     *
1606     * @param context the context is required only if the time is shown
1607     * @param millis a point in time in UTC milliseconds
1608     * @param flags a bit mask of formatting options
1609     * @return a string containing the formatted date/time.
1610     */
1611    public static String formatDateTime(Context context, long millis, int flags) {
1612        return formatDateRange(context, millis, millis, flags);
1613    }
1614
1615    /**
1616     * @return a relative time string to display the time expressed by millis.  Times
1617     * are counted starting at midnight, which means that assuming that the current
1618     * time is March 31st, 0:30:
1619     * <ul>
1620     *   <li>"millis=0:10 today" will be displayed as "0:10"</li>
1621     *   <li>"millis=11:30pm the day before" will be displayed as "Mar 30"</li>
1622     * </ul>
1623     * If the given millis is in a different year, then the full date is
1624     * returned in numeric format (e.g., "10/12/2008").
1625     *
1626     * @param withPreposition If true, the string returned will include the correct
1627     * preposition ("at 9:20am", "on 10/12/2008" or "on May 29").
1628     */
1629    public static CharSequence getRelativeTimeSpanString(Context c, long millis,
1630            boolean withPreposition) {
1631
1632        long now = System.currentTimeMillis();
1633        long span = now - millis;
1634
1635        if (sNowTime == null) {
1636            sNowTime = new Time();
1637            sThenTime = new Time();
1638        }
1639
1640        sNowTime.set(now);
1641        sThenTime.set(millis);
1642
1643        String result;
1644        int prepositionId;
1645        if (span < DAY_IN_MILLIS && sNowTime.weekDay == sThenTime.weekDay) {
1646            // Same day
1647            int flags = FORMAT_SHOW_TIME;
1648            result = formatDateRange(c, millis, millis, flags);
1649            prepositionId = R.string.preposition_for_time;
1650        } else if (sNowTime.year != sThenTime.year) {
1651            // Different years
1652            int flags = FORMAT_SHOW_DATE | FORMAT_SHOW_YEAR | FORMAT_NUMERIC_DATE;
1653            result = formatDateRange(c, millis, millis, flags);
1654
1655            // This is a date (like "10/31/2008" so use the date preposition)
1656            prepositionId = R.string.preposition_for_date;
1657        } else {
1658            // Default
1659            int flags = FORMAT_SHOW_DATE | FORMAT_ABBREV_MONTH;
1660            result = formatDateRange(c, millis, millis, flags);
1661            prepositionId = R.string.preposition_for_date;
1662        }
1663        if (withPreposition) {
1664            Resources res = c.getResources();
1665            result = res.getString(prepositionId, result);
1666        }
1667        return result;
1668    }
1669
1670    /**
1671     * Convenience function to return relative time string without preposition.
1672     * @param c context for resources
1673     * @param millis time in milliseconds
1674     * @return {@link CharSequence} containing relative time.
1675     * @see #getRelativeTimeSpanString(Context, long, boolean)
1676     */
1677    public static CharSequence getRelativeTimeSpanString(Context c, long millis) {
1678        return getRelativeTimeSpanString(c, millis, false /* no preposition */);
1679    }
1680
1681    private static Time sNowTime;
1682    private static Time sThenTime;
1683}
1684