IOS 关于取消延迟执行函数的种种。performSelector与cancelPreviousPerformRequestsWithTarget

@interface NSObject (NSDelayedPerforming)  
  
- (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay inModes:(NSArray *)modes;  
- (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay;  
+ (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget selector:(SEL)aSelector object:(id)anArgument;  
+ (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget;  
  
@end

最近看到大家对cancelPreviousPerformRequestsWithTarget不能取消带参数的

(void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay; 情况，写了一点点代码调试了一下，发现如果是带参数，那取消时的参数也要一致，否则不能取消成功。开始延迟执行：

[self performSelector:@selector(didRuninCurrModel:) withObject:[NSNumber numberWithBool:YES] afterDelay:3.0f];

[self performSelector:@selector(didRuninCurrModelNoArgument) withObject:nil afterDelay:3.0f];

假如在三秒内执行以下取消方法，则结果分别为：

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:[NSNumber numberWithBool:YES]];//可以取消成功。  
  
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:[NSNumber numberWithBool:NO]];//不能取消成功。参数不匹配  
  
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:nil];//不能取消成功。参数不匹配  
  
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModelNoArgument) object:nil];//可以成功取消  
  
[NSObject cancelPreviousPerformRequestsWithTarget:self];//可以成功取消全部。  
[[self class] cancelPreviousPerformRequestsWithTarget:self];//可以成功取消全部。