内容简介：业务中有些场景需要做延时处理，一般采用的是
业务中有些场景需要做延时处理，一般采用的是 dispatch_after
这个 GCD 方法来实现，但是缺点是这种延时没办法取消，于是乎有了：
[self performSelector:@selector(myDelayedMethod) withObject: self afterDelay: desiredDelay]; [NSObject cancelPreviousPerformRequestsWithTarget: self selector:@selector(myDelayedMethod) object: self];
用了上面的方法，可以随时取消还没有执行的延时，但这个 API 只支持一个参数，有时候并不能满足我们的要求，网上搜索都提到了用 NSInvocation 或者 dispatch_after代替，但是这些方法都存在不能延时或者不能取消的问题，
于是试给 NSObject 扩展一下，让其支持多个参数，并支持cancelPreviousPerformRequestsWithTarget
取消，原理其实很简单，直接贴代码：
NSObject+Additions.h
@interface NSObject (Additions) - (void)performSelector:(SEL)aSelector withObject:(id)argument0 withObject:(id)argument1 afterDelay:(NSTimeInterval)delay; - (void)performSelector:(SEL)aSelector withObject:(id)argument0 withObject:(id)argument1 afterDelay:(NSTimeInterval)delay inModes:(NSArray<NSRunLoopMode> *)modes; + (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget selector:(SEL)aSelector object:(id)argument0 object:(id)argument1; @end
NSObject+Additions.m
@implementation NSObject (Additions)
- (void)performSelector:(SEL)aSelector withObject:(id)argument0 withObject:(id)argument1 afterDelay:(NSTimeInterval)delay {
[self performSelector:aSelector withObject:argument0 withObject:argument1 afterDelay:delay inModes:@[NSDefaultRunLoopMode]];
}
- (void)performSelector:(SEL)aSelector withObject:(id)argument0 withObject:(id)argument1 afterDelay:(NSTimeInterval)delay inModes:(NSArray<NSRunLoopMode> *)modes {
NSArray *arguments = [NSArray arrayWithObjects:NSStringFromSelector(aSelector), argument0, argument1, nil];
[self performSelector:@selector(_performWithArguments:) withObject:arguments afterDelay:delay inModes:modes];
}
+ (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget selector:(SEL)aSelector object:(id)argument0 object:(id)argument1 {
NSArray *arguments = [NSArray arrayWithObjects:NSStringFromSelector(aSelector), argument0, argument1, nil];
[self cancelPreviousPerformRequestsWithTarget:aTarget selector:@selector(_performWithArguments:) object:arguments];
}
- (void)_performWithArguments:(NSArray *)arguments {
SEL aSelector = NSSelectorFromString([arguments firstObject]);
NSMethodSignature *signature = [self methodSignatureForSelector:aSelector];
NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
[invocation setTarget:self];
[invocation setSelector:aSelector];
for (NSUInteger i = 1; i < arguments.count; i++) {
id obj = arguments[i];
[invocation setArgument:&obj atIndex:i + 1];
}
[invocation invoke];
}
@end
以上所述就是小编给大家介绍的《让 performSelector:withObject:afterDelay: 支持多个参数》，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持！
本站部分资源来源于网络，本站转载出于传递更多信息之目的，版权归原作者或者来源机构所有，如转载稿涉及版权问题，请联系我们。
