很多项目中，都会涉及到倒计时的功能， 发送完验证码开始倒计时，针对这个我个人封装了一个简单的方法来实现此功能， 话不多说，上干货！
首先我是在UIButton的一个延展类里面添加了一个方法
/**
* 倒计时按钮
*
* @param timeLine 倒计时总时间
*/
- (void)startCountDownWithTime:(NSInteger)timeLine;
然后在.m中实现
- (void)startCountDownWithTime:(NSInteger)timeLine{
NSString *subTitle = @"重新发送";
UIColor *defultColor = UGUColorFromRGB_0x(0xed145b);
UIColor *runningColor = UGUColorFromRGB_0x(0xd5d5d5);
//倒计时时间
__block NSInteger timeOut = timeLine;
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
//每秒执行一次
dispatch_source_set_timer(_timer, dispatch_walltime(NULL, 0), 1.0 * NSEC_PER_SEC, 0);
dispatch_source_set_event_handler(_timer, ^{
//倒计时结束，关闭
if (timeOut <= 0) {
dispatch_source_cancel(_timer);
dispatch_async(dispatch_get_main_queue(), ^{
[self setTitle:subTitle forState:UIControlStateNormal];
self.userInteractionEnabled = YES;
self.layer.borderColor = [defultColor CGColor];
[self setTitleColor:defultColor forState:UIControlStateNormal];
});
} else {
self.userInteractionEnabled = YES;
int allTime = (int)timeLine + 1;
int seconds = timeOut % allTime;
NSString *timeStr = [NSString stringWithFormat:@"%0.1d", seconds];
dispatch_async(dispatch_get_main_queue(), ^{
[self setTitle:[NSString stringWithFormat:@"%@%@",timeStr,@"s"] forState:UIControlStateNormal];
self.layer.borderColor = [runningColor CGColor];
[self setTitleColor:runningColor forState:UIControlStateNormal];
self.userInteractionEnabled = NO;
});
timeOut--;
}
});
dispatch_resume(_timer);
}
以上就是全部代码，怎么样 ，是不是感觉很简单呢？
希望可以帮到大家 ~~~~
