024-计时器

#import 

@interface JFWeakTimerTargetObject : NSObject

+ (NSTimer * _Nonnull)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(nullable id)aTarget selector:(_Nonnull SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;

@end

#import "JFWeakTimerTargetObject.h"

@interface JFWeakTimerTargetObject ()

@property (nonatomic, weak) id target;
@property (nonatomic, assign) SEL selector;

@end

@implementation JFWeakTimerTargetObject

+ (NSTimer * _Nonnull)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(nullable id)aTarget selector:(_Nonnull SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo {
    //创建当前类对象
    JFWeakTimerTargetObject *object = [[JFWeakTimerTargetObject alloc] init];
    object.target = aTarget;
    object.selector = aSelector;
    return [NSTimer scheduledTimerWithTimeInterval:ti target:object selector:@selector(fire:) userInfo:userInfo repeats:yesOrNo];
}

- (void)fire:(id)obj {
    [self.target performSelector:self.selector withObject:obj afterDelay:0.0];
}

@end