时间倒叙

#pragma mark - 倒计时

- (void)timeCountDown

{

__block int timeout = 59; //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, ^{

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

_gainVerificationButton.userInteractionEnabled = YES;

_gainVerificationButton.backgroundColor = [UIColor lightGrayColor];

[_gainVerificationButton setTitle:@"获取验证码" forState:UIControlStateNormal];

});

}else{

int seconds = timeout % 60;

NSString *strTime = [NSString stringWithFormat:@"%d秒后重发", seconds];

dispatch_async(dispatch_get_main_queue(), ^{

_gainVerificationButton.userInteractionEnabled = NO;

_gainVerificationButton.backgroundColor = [UIColor lightGrayColor];

//设置界面的按钮显示 根据自己需求设置

[_gainVerificationButton setTitle:strTime forState:UIControlStateNormal];

});

timeout—;

}

});

dispatch_resume(_timer);

}