__block int timeout = 60;

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, ^{

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 根据自己需求设置

[self.getCode setTitle:@"发送验证码" forState:UIControlStateNormal];

self.getCode.userInteractionEnabled = YES;

});

}else{

int seconds = timeout % 60;

NSString *strTime = [NSString stringWithFormat:@"%.2d", seconds];

dispatch_async(dispatch_get_main_queue(), ^{

//设置界面的按钮显示 根据自己需求设置

//NSLog(@"____%@",strTime);

//[UIView beginAnimations:nil context:nil];

// [UIView setAnimationDuration:1];

[self.getCode setTitle:[NSString stringWithFormat:@"%@秒后重新发送",strTime] forState:UIControlStateNormal];

//[UIView commitAnimations];

self.getCode.userInteractionEnabled = NO;

});

timeout--;

}

});

dispatch_resume(_timer);

//注释:  self.getCode就是你点击的button,把以上代码复制到点击button的点击事件中.