在Objective C中每隔几秒重复一次方法

@interface MyTimer : NSObject
@end

@implementation MyTimer

- (void)timerDidFire:(NSTimer *)timer {
    // 每次触发时，将当前时间与上一次触发的时间进行比较，判断是否已经过了指定的时间间隔
    NSDate *now = [NSDate date];
    NSDate *lastFire = [self.timer.userInfo[0] objectForKey:@"lastFire"];
    NSTimeInterval interval = [now timeIntervalSinceDate:lastFire];
    if (interval >= self.interval) {
        // 执行需要重复执行的方法
        [self.timer invalidate];
        self.timer = nil;
        [self performSelector:@selector(timerDidFire:) withObject:nil afterDelay:self.interval];
        self.interval = [self.timer.userInfo[0] objectForKey:@"interval"] ?: 0;
        self.lastFire = now;
    }
}

@end

@interface MyClass : NSObject
@end

@implementation MyClass

- (void)startTimer {
    MyTimer *timer = [[MyTimer alloc] init];
    timer.interval = 3.0; // 设置每隔3秒重复执行一次方法
    timer.lastFire = [NSDate date];
    timer.timer = [NSTimer scheduledTimerWithTimeInterval:timer.interval target:self selector:@selector(repeatedMethod) userInfo:nil repeats:YES];
}

- (void)repeatedMethod {
    NSLog(@"repeatedMethod");
}

@end

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        MyClass *obj = [[MyClass alloc] init];
        [obj startTimer];
    }
    return 0;
}