答：JustinB
（最佳答案）
就这个问题本身来讲，不应该用NSTimer进行操作。Coco2d框架可以提供一种调度程序（scheduler），将停止/继续这种指令融进游戏中，使用方法如下：

-(id) init { if( ! [super init] ) return nil; // schedule timer [self schedule: @selector(tick:)]; [self schedule: @selector(tick2:) interval:0.5]; return self; } -(void) tick: (ccTime) dt { // bla bla bla } -(void) tick2: (ccTime) dt { // bla bla bla }

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答：seenu
在cocos2d中，定时器有一种默认更新的功能，所以可以尝试如下方法：

[self schedule:@selector(update:)]; - (void)update:(ccTime)dt { }

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答：Ziminji
如果不用"schedule"的方法，而是想用NSTimer创建定时器的话，你可以按照下述方法创建一个类（class）：
ZIMCountdownTicker.h

#import  extern NSString * const ZIMCountdownTickerTickAction; extern NSString * const ZIMCountdownTickerResetAction; @protocol ZIMCountdownTickerProtocol; /*! @class ZIMCountdownTicker @discussion This class creates a countdown ticker. @updated 2011-03-05 */ @interface ZIMCountdownTicker : NSObject { @private NSTimer *_timer; id _delegate; NSTimeInterval _interval; double _period; double _value; } /*! @method initWithDelegate:withTimeInterval:forTimePeriod: @discussion This method instantiate an instance of this class with the specified parameters. @param delegate A reference to a class that has implemented ZIMCountdownTickerProtocol. @param interval The time interval in seconds to be used when running the countdown ticker. @param period The time period in seconds for which countdown ticker will run. @updated 2011-03-05 */ - (id) initWithDelegate: (id)delegate withTimeInterval: (NSTimeInterval)interval forTimePeriod: (double)period; /*! @method start @discussion This method will start the countdown ticker. @updated 2011-03-05 */ - (void) start; /*! @method stop @discussion This method will stop the countdown ticker. @updated 2011-03-05 */ - (void) stop; /*! @method reset @discussion This method will reset the countdown ticker. @updated 2011-03-06 */ - (void) reset; /*! @method value @discussion This method will return the countdown ticker's current value; however, using this method will cause the ticker to stop. @return The countdown ticker's current value. @updated 2011-03-05 */ - (double) value; @end @protocol ZIMCountdownTickerProtocol  @optional /*! @method countdownTicker:didUpdateValue:withAction: @discussion This method will notify the delegate with the current value. @param ticker A reference to tiggering ticker. @param value The current value. @param action The action that tiggered this method. @updated 2011-03-05 */ - (void) countdownTicker: (ZIMCountdownTicker *)ticker didUpdateValue: (double)value withAction: (NSString *)action; /*! @method countdownTickerDidFinish: @discussion This method will notify the delegate that the countdown ticker finished. @param ticker A reference to tiggering ticker. @updated 2011-03-05 */ - (void) countdownTickerDidFinish: (ZIMCountdownTicker *)ticker; @end

ZIMCountdownTicker.m

// Ziminji Classes #import "ZIMCountdownTicker.h" NSString * const ZIMCountdownTickerTickAction = @"ticker.tick"; NSString * const ZIMCountdownTickerResetAction = @"ticker.reset"; /*! @category ZIMCountdownTicker (Private) @discussion This category defines the prototypes for this class's private methods. @updated 2011-03-05 */ @interface ZIMCountdownTicker (Private) /*! @method countdown: @discussion This method is called by the timer to decrement the counter's value and will send the delegate the updated value. @param timer The timer currently in use. @updated 2011-03-06 */ - (void) countdown: (NSTimer *)timer; @end @implementation ZIMCountdownTicker - (id) initWithDelegate: (id)delegate withTimeInterval (NSTimeInterval)interval forTimePeriod: (double)period { if (self = [super init]) { _delegate = delegate; _interval = interval; _period = period; _value = period; _timer = nil; } return self; } - (void) start { if (_timer == nil) { _timer = [NSTimer scheduledTimerWithTimeInterval: _interval target: self selector: @selector(countdown:) userInfo: nil repeats: YES]; } } - (void) stop { if (_timer != nil) { [_timer invalidate]; _timer = nil; } } - (void) reset { [self stop]; _value = _period; if ((_delegate != nil) && [_delegate respondsToSelector: @selector(countdownTicker:didUpdateValue:withAction:)]) { [_delegate countdownTicker: self didUpdateValue: _value withAction: ZIMCountdownTickerResetAction]; } } - (double) value { [self stop]; return _value; } - (void) countdown: (NSTimer *)timer { _value -= 1; if ((_delegate != nil) && [_delegate respondsToSelector: @selector(countdownTicker:didUpdateValue:withAction:)]) { [_delegate countdownTicker: self didUpdateValue: _value withAction: ZIMCountdownTickerTickAction]; } if (_value <= 0) { [self stop]; if ((_delegate != nil) && [_delegate respondsToSelector: @selector(countdownTickerDidFinish:)]) { [_delegate countdownTickerDidFinish: self]; } } } - (void) dealloc { if (_delegate != nil) { [_delegate release]; } if (_timer != nil) { [_timer invalidate]; } [super dealloc]; } @end

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答：lostInTransit
（反面教材）

-(id) init { if( ! [super init] ) return nil; // schedule timer [self schedule: @selector(tick:)]; [self schedule: @selector(tick2:) interval:0.5]; return self; } -(void) tick: (ccTime) dt { //some function here } -(void) tick2: (ccTime) dt { //some function here }