倒计时

@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic, assign) NSInteger count;

- (void)startTimer:(NSInteger)time {
    [self endTimer];
    _count = time;
    self.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerAction:) userInfo:nil repeats:YES];
    [self timerAction:nil];
}

- (void)timerAction:(NSTimer *)timer {
    _count -- ;
    if (_count <= 0) {
        [self endTimer];
        self.verificbutton.enabled = YES;
        
        [self.verificbutton setTitleColor:[UIColor colorWithHex:0x428DF4] forState:UIControlStateDisabled];
        [self.verificbutton setTitle:@"XXXXXX" forState:UIControlStateNormal];
        return;
    }
    [self.verificbutton setTitleColor:[UIColor colorWithHex:0x428DF4] forState:UIControlStateDisabled];
    [self.verificbutton setTitle: [NSString stringWithFormat:@"%zdS", _count] forState:UIControlStateNormal];
}

- (void)endTimer {
    if (self.timer) {
        [self.timer invalidate];
        self.timer = nil;
    }
}