My OC Growth path (date and time of review)

Attention:

1. Calculate the calendar in the current month

Calculated for a total of several days within one months:

Gets the number of days in the month-(Nsinteger) getnumberofdaysinmonth{    nscalendar * calendar = [[Nscalendar alloc] Initwithcalendaridentifier:nsgregoriancalendar]; The algorithm for the specified calendar    nsdate * currentdate = [NSDate date];//This date can be given yourself    nsrange range = [Calendar Rangeofunit:nsdaycalenda Runit                                   inunit:nsmonthcalendarunit                                  fordate:currentdate];    return range.length;}

Gets the number of days of the week in the month

/** * Get all days in the month is weeks */-(void) getalldayswithcalender{Nsuinteger daycount = [self getnumberofdaysinmonth];//One months total days    NSDateFormatter * formatter = [[NSDateFormatter alloc] init];    NSDate * currentdate = [NSDate Date];    [Formatter setdateformat:@ "yyyy-mm"];    NSString * str = [formatter stringfromdate:currentdate];    [Formatter setdateformat:@ "YYYY-MM-DD"];    Nsmutablearray * Alldaysarray = [[Nsmutablearray alloc] init];        for (Nsinteger i = 1; I <= daycount; i++) {NSString * sr = [nsstring stringwithformat:@ "%@-%ld", str,i];        NSDate *sudate = [Formatter DATEFROMSTRING:SR];    [Alldaysarray addobject:[self getweekdaywithdate:sudate]; } NSLog (@ "Alldaysarray%@", Alldaysarray);} /** * Get data for one day * * Gets the date specified is the days of the week */-(ID) getweekdaywithdate: (NSDate *) date{Nscalendar * calendar = [[Nscalendar alloc ] Initwithcalendaridentifier:nsgregoriancalendar];    The algorithm for the specified calendar nsdatecomponents *comps = [Calendar Components:nsweekdaycalendarunit fromdate:date];1 is Sunday, 2 is Week 13. And so on return @ ([comps weekday]);} 

2. Compare two dates, compare: Method

Returns the Nscomparisonresult enumeration value

The enumeration type contains three values of nsorderedascending, Nsorderedsame, and nsordereddescending

3.

NSDate--Represents an absolute point in time
Nstimezone--Time zone information
Nslocale--Localization information
Nsdatecomponents--A class that encapsulates a specific date, time, week, quarter, etc.
Nscalendar--Calendar class, which provides most of the date compute interfaces and allows you to convert between NSDate and nsdatecomponents

NSDateFormatter--Used to convert between dates and strings

First, NSDate

1. Get nsdatensdate* date1 = [NSDate Date] representing the current date and time; NSLog (@ "%@", date1);//2. Gets the date from the current time, after the day, or 3 days before the date nsdate* date2 = [[NSDate alloc]initwithtimeintervalsincenow:3600* 24]; NSLog (@ "%@", date2); nsdate* date3 = [[NSDate alloc]initwithtimeintervalsincenow: -3*3600*24]; NSLog (@ "%@", date3);//3. Date from January 1, 1970, 20 years later nsdate* date4 = [nsdate datewithtimeintervalsince1970:3600 * 24 * 366 * 2 0]; NSLog (@ "%@", date4); nslocale* cn = [Nslocale Currentlocale]; NSLog (@ "%@", [Date1 DESCRIPTIONWITHLOCALE:CN]);//4. Get two dates between the earlier dates/get two dates later on the date nsdate* earlier = [Date1 earlierdate: DATE2]; nsdate* later = [Date1 laterdate:date2];switch ([date1 compare:date3]) {case Nsorderedascending:nslog (@ "Date1 before Date3 Break;case Nsorderedsame:nslog (@ "date1 and date3 date equal"); Break;case Nsordereddescending:nslog (@ "Date1 is located after Date3"); break;} 5. Get the time difference between two times/Gets the time difference between the specified and present times

NSLog (@ "Date1 and date3 time difference%g seconds", [Date1 timeintervalsincedate:date3]);

NSLog (@ "Date2 and now time difference%g seconds", [Date2 Timeintervalsincenow]);

　　

Second, date format device

1. Obtain the date from January 1, 1970 onwards, 20 years after nsdate* dt = [nsdate datewithtimeintervalsince1970:3600 * 24 * 366 * 20]; nslocale* locales[] = [[Nslocale alloc] initwithlocaleidentifier:@ "ZH_CN"];nsdateformatter* df;// Create DateFormat object for the above nslocale df = [[NSDateFormatter alloc] init];//2. Set the date and time style of the NSDateFormatter [DF Setdatestyle: Nsdateformattershortstyle]; [DF settimestyle:nsdateformattershortstyle];//Set Custom Formatter template [Df2 setdateformat:@ "A.D. yyyy mm month DD day hh mm"];//3. Executes the formatted NSLog (@ "%@", [Df2 Stringfromdate:dt]); nsstring* datestr = @ "2013-03-02"; nsdateformatter* df3 = [[NSDateFormatter alloc] init];//4. Format template based on date string [df3 setdateformat:@ "Yyyy-mm-dd"];// Converts a string to a NSDate object nsdate* date2 = [Df3 datefromstring:datestr]; NSLog (@ "%@", date2);

　　

Third, calendar

1. Get the Calendar object that represents the Gregorian calendar Nscalendar *gregorian = [[Nscalendar alloc]initwithcalendaridentifier:nsgregoriancalendar];// 2. Get the current date nsdate* dt = [NSDate date];//3. Defines a flag for a time field that specifies the information for the specified year, month, day, hour, minute, second, unsigned unitflags = Nsyearcalendarunit |  Nsmonthcalendarunit | Nsdaycalendarunit |  Nshourcalendarunit | Nsminutecalendarunit | Nssecondcalendarunit | nsweekdaycalendarunit;//4. Get information on different time fields nsdatecomponents* comp = [Gregorian components:unitflags fromdate:dt];//5. Gets the numeric nslog for each time field (@ "Now is%ld years", comp.year); NSLog (@ "Now is%ld months", comp.month); NSLog (@ "Now is%ld Day", Comp.day); NSLog (@ "Now is%ld", comp.hour); NSLog (@ "Now is%ld", comp.minute); NSLog (@ "Now is%ld seconds", Comp.second); NSLog (@ "Now is week%LD", comp.weekday);//6. Create a Nsdatecomponents object again nsdatecomponents* comp2 = [[Nsdatecomponents alloc] init];//7. Set the value of each time field comp2.year = 2013;comp2.month = 4;comp2.day = 5;comp2.hour = 18;comp2.minute = 34;//8. by nsdatecompon Ents contains the value of the Time field to restore the NSDate object nsdate *date = [Gregorian DATEFROMCOMPONENTS:COMP2]; NSLog (@ "Gets the date:%@", date);

　　

My OC Growth path (date and time of review)