Foundation Framework (7) Time operation

The main classes related to time operations are:

NSDate

Nsdatformatter

Nscalendar

Nsdatecomponents

Also introduces a Timer object Nstimer

• NSDate

Used to describe a datetime, providing some basic time acquisition and comparison methods

+ (Instancetype) Date//Current date time + (Instancetype) Datewithtimeintervalsincenow: (nstimeinterval) seconds-( Nscomparisonresult) Compare: (NSDate *) anotherdate-(nstimeinterval) timeintervalsincedate: (NSDate *) anotherDate

• NSDateFormatter

NSDate object for string formatting

@property (copy) NSString *dateformat//Format-(NSString *) Stringfromdate: (NSDate *) date-(NSDate *) Datefromstring: ( NSString *) string

• Nscalendar

Calendar object, on top of the calendar object, to convert NSDate to Nsdatecomponents

+ (Nscalendar *) currentcalendar-(nsdatecomponents *) components: (nscalendarunit) unitflags fromdate: (nsdate*) date-( NSDate *) Datefromcomponents: (nsdatecomponents *) comps

• Nsdatecomponents

Describes NSDate objects in a way that is used for objects

@property nsinteger year@property nsinteger month@property nsinteger day@property nsinteger hour@property NSInteger Minute@property Nsinteger Second ...

• Nstimer

Nstimer is used to start a timer and perform the specified action at timed intervals.

The specified operation is specified with the SEL (method) object

Direct Start Timer + (Nstimer *) Scheduledtimerwithtimeinterval: (nstimeinterval) seconds target: (ID) Target selector: (SEL) Aselector UserInfo: (ID) UserInfo repeats: (BOOL) repeats//Create a timer that does not start directly + (Nstimer *) Timerwithtimeinterval: ( Nstimeinterval) seconds target: (ID) Target selector: (SEL) Aselector userInfo: (ID) UserInfo repeats: (BOOL) repeats

Other control methods of the timer:

-(void) fire//Start-(void) invalidate//disable

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Foundation Framework (7) Time operation