iOS 几种定定时器实现

最新推荐文章于 2021-04-13 17:33:41 发布

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最新推荐文章于 2021-04-13 17:33:41 发布

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分类专栏：移动开发文章标签： ios

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本文介绍了使用CGD及NSTimer两种方式实现倒计时功能的具体代码示例。CGD部分通过dispatch_source创建定时器，并利用dispatch_queue进行调度；而NSTimer则直接采用schedule方法启动定时任务。两种方案均实现了按钮禁用与倒计时显示等功能。

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1.CGD定时器

- (IBAction)countDown:(id)sender {
    __block int currentSeconds = 60;//设置总时间
    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_TIME_NOW, 1.0 * NSEC_PER_SEC, 0 * NSEC_PER_SEC);
    dispatch_source_set_event_handler(timer, ^{
        if (currentSeconds <= 0) {
            dispatch_source_cancel(timer);
            dispatch_async(dispatch_get_main_queue(), ^{
                self.timeButton.enabled = YES;
                [self.timeButton setTitle:@"验证" forState:UIControlStateNormal];
            });
        } else {
            currentSeconds--;
            dispatch_async(dispatch_get_main_queue(), ^{
                self.timeButton.enabled = NO;
                [self.timeButton setTitle:[NSString stringWithFormat:@"%d秒",currentSeconds] forState:UIControlStateNormal];
            });
        }
    });
    //启动定时器
    dispatch_resume(timer);
}

2.NSTimer定时器

-(void)lookBackClick:(UIButton *)btn
{
    
    NSDictionary *params = @{@"phone":fieldMobile.text};
    [NetworkHandle post:CAPTCHA_URL parameters:params success:^(AFHTTPRequestOperation *operation, NSDictionary *response) {
        NSLog(@"------%@",operation.responseString);
        NSDictionary *rs = [NSJSONSerialization JSONObjectWithData:operation.responseData options:NSJSONReadingMutableContainers error:nil];
        
        if (rs) {
            codeString = rs[@"ds"];
            seconds = 60;
            [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(onTimer:) userInfo:nil repeats:YES];
            [getButton setEnabled:NO];

        }
    }];
}
- (void)onTimer:(id)userInfo {
    [getButton setTitle:[NSString stringWithFormat:@"%d", --seconds] forState:UIControlStateDisabled];
    
    if (seconds == 0) {
        [getButton setTitle:@"获取验证码" forState:UIControlStateNormal];
        [getButton setEnabled:YES];

        NSTimer *timer = (NSTimer *)userInfo;
        [timer invalidate];
    }
}