iOS 关于取消延迟执行函数 performSelector与cancelPreviousPerformRequestsWithTarget

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1. @interface NSObject (NSDelayedPerforming)  
2.   
3. - (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay inModes:(NSArray *)modes;  
4. - (void)performSelector:(SEL)aSelector withObject:(id)anArgument afterDelay:(NSTimeInterval)delay;  
5. + (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget selector:(SEL)aSelector object:(id)anArgument;  
6. + (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget;  
7.   
8. @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：

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1. [self performSelector:@selector(didRuninCurrModel:) withObject:[NSNumber numberWithBool:YES] afterDelay:3.0f];  
2.   
3. [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：

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1. [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:[NSNumber numberWithBool:YES]];//可以取消成功。  
2.   
3. [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:[NSNumber numberWithBool:NO]];//不能取消成功。参数不匹配  
4.   
5. [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModel:) object:nil];//不能取消成功。参数不匹配  
6.   
7. [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(didRuninCurrModelNoArgument) object:nil];//可以成功取消  
8.   
9. [NSObject cancelPreviousPerformRequestsWithTarget:self];//可以成功取消全部。  
10. [[self class] cancelPreviousPerformRequestsWithTarget:self];//可以成功取消全部。