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NSTimer class reference

Authors

Andrew Kachites McCallum (mccallum@gnu.ai.mit.edu)
Richard Frith-Macdonald (rfm@gnu.org)

Version: 1.37

Date: 2004/09/07 16:54:16

Copyright: (C) 1995, 1996, 1999 Free Software Foundation, Inc.

Software documentation for the NSTimer class

NSTimer : NSObject

Declared in:
Foundation/NSTimer.h
Standards:

An NSTimer provides a way to send a message at some time in the future, possibly repeating every time a fixed interval has passed. To use a timer, you can either create one that will automatically be added to the run loop in the current thread (using the -addTimer:forMode: method), or you can create it without adding it then add it to an NSRunLoop explicitly later.


Instance Variables

Method summary

scheduledTimerWithTimeInterval: invocation: repeats: 

+ (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti invocation: (NSInvocation*)invocation repeats: (BOOL)f;

Create a timer which will fire after ti seconds and, if f is YES, every ti seconds thereafter. On firing, invocation will be performed.
This timer will automatically be added to the current run loop and will fire in the default run loop mode.


scheduledTimerWithTimeInterval: target: selector: userInfo: repeats: 

+ (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti target: (id)object selector: (SEL)selector userInfo: (id)info repeats: (BOOL)f;

Create a timer which will fire after ti seconds and, if f is YES, every ti seconds thereafter. On firing, the target object will be sent a message specified by selector and with the object info as an argument.
This timer will automatically be added to the current run loop and will fire in the default run loop mode.


timerWithTimeInterval: invocation: repeats: 

+ (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti invocation: (NSInvocation*)invocation repeats: (BOOL)f;

Create a timer which will fire after ti seconds and, if f is YES, every ti seconds thereafter. On firing, invocation will be performed.
NB. To make the timer operate, you must add it to a run loop.


timerWithTimeInterval: target: selector: userInfo: repeats: 

+ (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti target: (id)object selector: (SEL)selector userInfo: (id)info repeats: (BOOL)f;

Create a timer wchich will fire after ti seconds and, if f is YES, every ti seconds thereafter. On firing, the target object will be sent a message specified by selector and with the value info as an argument.
NB. To make the timer operate, you must add it to a run loop.


fire 

- (void) fire;

Fires the timer... either performs an invocation or ssends a message to a target object, depending on how the timer was set up.
If the timer is not set to repeat, it is automatically invalidated.


fireDate 

- (NSDate*) fireDate;

Returns the date/time at which the timer is next due to fire.


initWithFireDate: interval: target: selector: userInfo: repeats: 

- (id) initWithFireDate: (NSDate*)fd interval: (NSTimeInterval)ti target: (id)object selector: (SEL)selector userInfo: (id)info repeats: (BOOL)f;
This is a designated initialiser for the class.

Initialise the receive, a newly allocated NSTimer object.
The fd argument specifies an initial fire date... if it is not supplied (a nil object) then the ti argument is used to create a start date relative to the current time.
The ti argument specifies the time (in seconds) between the firing. If it is less than or equal to 0.0 then a small interval is chosen automatically.
The f argument specifies whether the timer will fire repeatedly or just once.
If the selector argument is zero, then then object is an invocation to be used when the timer fires. otherwise, the object is sent the message specified by the selector and with the timer as an argument.
The fd, object and info arguments will be retained until the timer is invalidated.


invalidate 

- (void) invalidate;

Marks the timer as invalid, causing its target/invocation and user info objects to be released.
Invalidated timers are automatically removed from the run loop when it detects them.


isValid 

- (BOOL) isValid;

Checks to see if the timer has been invalidated.


setFireDate: 

- (void) setFireDate: (NSDate*)fireDate;

Change the fire date for the receiver.
NB. You should NOT use this method for a timer which has been added to a run loop. The only time when it is safe to modify the fire date of a timer in a run loop is for a repeating timer when the timer is actually in the process of firing.


timeInterval 

- (NSTimeInterval) timeInterval;

Returns the interval beteen firings.


userInfo 

- (id) userInfo;

Returns the user info which was set for the timer when it was created, or nil if none was set or the timer is invalid.




Instance Variables for NSTimer Class

_date

@protected NSDate* _date;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_info

@protected id _info;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_interval

@protected NSTimeInterval _interval;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_invalidated

@protected BOOL _invalidated;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_repeats

@protected BOOL _repeats;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_selector

@protected SEL _selector;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.


_target

@protected id _target;

Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.






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