在app 注册或者登录 需要验证码的地方、为了避免短时间内刷验证码、往往会加上一层验证。

倒计时结束后、可以重新获取！

代码实现如下：

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 // _countdowntime 倒计时总时间； //_timer 定时器 - (void)starttime:(uibutton *)verificationcodebutton { __block nsinteger timeout = [_countdowntime integervalue]; dispatch_queue_t queue = dispatch_get_global_queue(dispatch_queue_priority_default, 0); _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); dispatch_source_set_event_handler(_timer, ^{ if(timeout<=0){ dispatch_source_cancel(_timer); dispatch_async(dispatch_get_main_queue(), ^{ [verificationcodebutton settitle:@"重新获取" forstate:uicontrolstatenormal]; verificationcodebutton.userinteractionenabled = yes; verificationcodebutton.alpha = 1.0; verificationcodebutton.backgroundcolor = [uicolor whitecolor]; }); } else { nsstring *strtime = [nsstring stringwithformat:@"%lds", (long)timeout]; dispatch_async(dispatch_get_main_queue(), ^{ [verificationcodebutton settitle:strtime forstate:uicontrolstatenormal]; verificationcodebutton.userinteractionenabled = no; verificationcodebutton.backgroundcolor = [uicolor lighttextcolor]; }); timeout--; } }); dispatch_resume(_timer); }

总结

以上所述是小编给大家介绍的ios 验证码按钮倒计时功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！

原文链接：http://www.cnblogs.com/jukaiit/archive/2017/07/26/7238829.html