IOS 关于取消延迟执行函数的种种。performSelector与cancelPreviousPerformRequestsWithTarget
http://blog.csdn.net/samuelltk/article/details/8994313
- @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。
代码下载地址:http://download.csdn.net/detail/samuelltk/5481327