[移动开发]iOS倒计时

@interface AuthCodeManager : NSObject

+ (void)getValidCode:(UIButton *)sendCodeButton;

@end

#import "AuthCodeManager.h"

@implementation AuthCodeManager

# pragma mark -- 验证码重新发送按钮

+ (void)getValidCode:(UIButton *)sendCodeButton{

?? ?

? ? [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];

? ? __block int count= 120;

? ? [sendCodeButton setTitle:[NSString stringWithFormat:@"%d s",count] forState:UIControlStateNormal];

? ? //定时器开始执行的延时时间

? ? NSTimeInterval delayTime = 1.0f;

? ? //定时器的间隔时间

? ? NSTimeInterval timeInterval = 1.0f;

? ? //创建子线程队列

? ? dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

? ? //使用之前创建的队列来创建计时器

? ? dispatch_source_t _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);

? ? //设置延时的执行时间，delayTime为要延时的秒数

? ? dispatch_time_t startDelayTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayTime*NSEC_PER_SEC));

? ? //设置计时器

? ? dispatch_source_set_timer(_timer, startDelayTime, timeInterval*NSEC_PER_SEC, 0.1*NSEC_PER_SEC);

? ? dispatch_source_set_event_handler(_timer, ^{

? ? //执行事件

? ? ? ? /**

?? ? ? ? * 回主线程更新UI

?? ? ? ? */

? ? count--;

? ? dispatch_async(dispatch_get_main_queue(), ^{

? ? if (count==0) {

? ? ? ? dispatch_cancel(_timer);//取消定时器

//? ? ? ? _timer = nil;

? ? ? ? sendCodeButton.enabled = YES;

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

? ? ? ? }

? ? else{

? ? ? ? sendCodeButton.enabled = NO;

? ? ? ? [sendCodeButton.titleLabel setText:[NSString stringWithFormat:@"%d s",count]];

? ? ? ? [sendCodeButton setTitle:[NSString stringWithFormat:@"%d s",count] forState:UIControlStateNormal];

?? ? ? ? }

? ? ? ? });

? ? });

? ? //启动计时器

? ? dispatch_resume(_timer);

}

@end