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:

1 //获取验证码按钮 2 - (IBAction)getButtonClick:(UIButton *)sender; 3  4 #pragma mark - 获取验证码 5 - (IBAction)getButtonClick:(UIButton *)sender 6 { 7     //正常状态下的背景颜色 8     UIColor *mainColor = [UIColorcolorWithRed:84/255.0green:180/255.0blue:98/255.0alpha:1.0f]; 9     //倒计时状态下的颜色10     UIColor *countColor = [UIColorlightGrayColor];11     [selfsetTheCountdownButton:sender startWithTime:5title:@"获取验证码"countDownTitle:@"s"mainColor:mainColor countColor:countColor];12 }13 14 #pragma mark - button倒计时15 - (void)setTheCountdownButton:(UIButton *)button startWithTime:(NSInteger)timeLine title:(NSString *)title countDownTitle:(NSString *)subTitle mainColor:(UIColor *)mColor countColor:(UIColor *)color {16     //倒计时时间17     __block NSInteger timeOut = timeLine;18     dispatch_queue_t queue =dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);19     dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,0, 0, queue);20     //每秒执行一次21     dispatch_source_set_timer(_timer,dispatch_walltime(NULL,0), 1.0 * NSEC_PER_SEC,0);22     dispatch_source_set_event_handler(_timer, ^{23 24         //倒计时结束，关闭25         if (timeOut == 0) {26             dispatch_source_cancel(_timer);27             dispatch_async(dispatch_get_main_queue(), ^{28                 button.backgroundColor = mColor;29                [button setTitle:titleforState:UIControlStateNormal];30                 button.userInteractionEnabled =YES;31             });32         } else {33             int seconds = timeOut % 60;34             NSString *timeStr = [NSStringstringWithFormat:@"%0.1d", seconds];35             dispatch_async(dispatch_get_main_queue(), ^{36                 button.backgroundColor = color;37                 [button setTitle:[NSStringstringWithFormat:@"%@%@",timeStr,subTitle]forState:UIControlStateNormal];38                 button.userInteractionEnabled =NO;39             });40             timeOut--;41         }42     });43     dispatch_resume(_timer);44 }