最近一个项目有获取手机短信跟邮箱验证码功能, 所以要加一个UIButton倒计时功能

例子代码如下:

- //获取验证码按钮
- - (IBAction)getButtonClick:(UIButton *)sender;
-
- #pragma mark - 获取验证码
- - (IBAction)getButtonClick:(UIButton *)sender
- {
-     //正常状态下的背景颜色
-     UIColor *mainColor = [UIColorcolorWithRed:84/255.0green:180/255.0blue:98/255.0alpha:1.0f];
-     //倒计时状态下的颜色
-     UIColor *countColor = [UIColorlightGrayColor];
-     [selfsetTheCountdownButton:sender startWithTime:5title:@"获取验证码"countDownTitle:@"s"mainColor:mainColor countColor:countColor];
- }
-
- #pragma mark - button倒计时
- - (void)setTheCountdownButton:(UIButton *)button startWithTime:(NSInteger)timeLine title:(NSString *)title countDownTitle:(NSString *)subTitle mainColor:(UIColor *)mColor countColor:(UIColor *)color {
-     //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(), ^{
-                 button.backgroundColor = mColor;
-                 [button setTitle:titleforState:UIControlStateNormal];
-                 button.userInteractionEnabled =YES;
-             });
-         } else {
-             int seconds = timeOut % 60;
-             NSString *timeStr = [NSStringstringWithFormat:@"%0.1d", seconds];
-             dispatch_async(dispatch_get_main_queue(), ^{
-                 button.backgroundColor = color;
-                 [button setTitle:[NSStringstringWithFormat:@"%@%@",timeStr,subTitle]forState:UIControlStateNormal];
-                 button.userInteractionEnabled =NO;
-             });
-             timeOut--;
-         }
-     });
-     dispatch_resume(_timer);
- }