
具体代码实现如下:
- (IBAction)sendMes:(UIButton *)sender {__block int timeout = 10 ; //倒计时时间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);dispatch_source_set_timer(_timer, dispatch_walltime(NULL, 0), 1.0 * NSEC_PER_SEC, 0); //每秒执行dispatch_source_set_event_handler(_timer, ^{ //每秒钟回调的方法 跟NSTimer 一样的的执行方法 if(timeout<=0){ //倒计时结束,关闭dispatch_source_cancel(_timer);dispatch_async(dispatch_get_main_queue(), ^{ //设置界面的按钮显示 [sender setTitle:@"发送验证码" forState:UIControlStateNormal]; sender.enabled = YES;}); }else{int seconds = timeout % 60;NSString *strTime = [NSString stringWithFormat:@"%d", seconds];dispatch_async(dispatch_get_main_queue(), ^{ NSLog(@"----%@", [NSThread currentThread]); //设置界面的按钮显示 [sender setTitle:[NSString stringWithFormat:@"(%@)重新获取",strTime] forState:UIControlStateDisabled]; sender.enabled = NO;});timeout--; }});//一定要调用resume 开启定时器的功能 } 这个button可以直接在storyboard中实现,button的背景颜色选为灰色,再设置一个背景图片,如上图的红色图片,button的type设置为:custom