Time and date in iOS

What do you say? Time and date are not great attributes, great features, but we must never be able to "snub" it.

One: How to "get the goods"--how to obtain time, date

//-=-== Current time------The "0 time zone" time is displayed by defaultNSDate * date1=[NSDate Date];//=-=-time Stamp//--1, the time is 60 seconds from 1970NSDate * date2=[nsdatedatewithtimeintervalsince1970: -];//--2,2000 YearNSDate * Date3=[nsdate datewithtimeintervalsincereferencedate: -* -];//-=--=-=---Now the time after "Nstimeinterval" startsNSDate * Date4=[nsdate Datewithtimeintervalsincenow: -* -];//-=-=-The date of "timeinterval" seconds after a date "Date1"NSDate * Date5=[nsdate datewithtimeinterval:60sincedate:date1];

Two: After getting the date and time, the format may be "Not what I want", what should I do?

Date formatting class: Nsformatter, you can get the format you want by this class, but be careful to format it on a certain basis:

Yyyy/yy: Year 2012/12

MM: Month

DD: "Japanese part"

HH: When

MM: Min

SS: Seconds

A:AM/PM (optional in 12-hour format)

ZZZ: Time zone

EEEE: Day of the week

The formatted string can also be converted back to the original nsdate type, but the string is formatted; (time default is 0 time zone, but after conversion is your current time zone)

/** Date format class: Nsformatter:nsobject*/NSDateFormatter* formatter=[[NSDate Formatter alloc] init];//-------= time converted to String =--------formatter.dateformat=@"yyyy lift mm head dd Hope hh Ming mm month ss a king zzz King Eeee"; NSString* datestr=[Formatter stringfromdate:date1]; NSLog (@"time turns into a string:%@", datestr);//-------= string converted to date-----=====/** The time at which the string is transferred is "time in the current time zone"*/NSString*string=@"2016 06 Head 28 hope 17 Ming 54 month gmt+8 King King Tuesday"; NSDate* Strdate=[formatter datefromstring:string]; NSLog (@"string Turn time:%@", strdate);

Three: Two dates of the morning and evening comparison

/** Compare Dates*/BOOL Flag=[Date1 Isequaltodate:date2];if(flag==NO) {NSLog (@"To think of my hometown"); }//--= Compare two dates sooner or later---=/** Return to an earlier time*/NSDate* date6=[Date1 Earlierdate:date2]; NSLog (@"%@", date6);/** Return to late time*/NSDate* date7=[Date1 Laterdate:date2]; NSLog (@"%@", Date7);}

Four: Date of control--uidatepicker

is to use Uidatepicker to select the time of the alarm;

How do I use it?

Uidatepicker * Picker=[[uidatepickeralloc] Initwithframe:cgrectmake (0, Kwidth, Kheight)];    Picker.backgroundcolor=[Uicolor cyancolor];    [Picker addtarget:selfaction: @selector (changeaction:) forcontrolevents:uicontroleventvaluechanged]; /*  */    picker.datepickermode=uidatepickermodedateandtime;    [Self.view Addsubview:picker];

It's so easy.

Uidatepicker:uicontrol How events can be added (AddTarget) to trigger events: uicontroleventvaluechanged

#pragma mark-value changed listener event-(void) Changeaction: (Uidatepicker *) P{nslog (@ "%@  ", P.date);}

Intended to catch the cicada, suddenly shut up.

Time and date in iOS