__block NSInteger timeout= 60; //倒计时时间 KWeakSelf 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(), ^{ KStrongSelf //设置界面的按钮显示 根据自己需求设置 self.getCodeBtn.enabled = YES; [self.getCodeBtn setTitle:@"获取验证码" forState:UIControlStateNormal]; }); }else{ self.getCodeBtn.enabled = NO; NSString *strTime = [NSString stringWithFormat:@"%zd秒",timeout]; dispatch_async(dispatch_get_main_queue(), ^{ //设置界面的按钮显示 根据自己需求设置 [self.getCodeBtn setTitle:strTime forState:UIControlStateNormal]; }); timeout--; } }); dispatch_resume(_timer);