Question

在我的应用中，我使用CATransition来滑动横幅视图。我的代码是这样的：

viewDidLoad中（）

- (void)viewDidLoad
{
    [super viewDidLoad];
    bannerList = [[NSMutableArray alloc] init];
    bannerList = [WebFunctions fetchBannerDataHavingUrl:@"banners/event"];

    NSTimer* timer = [NSTimer timerWithTimeInterval:3.0f target:self selector:@selector(updateLabel) userInfo:nil repeats:YES];
    [[NSRunLoop mainRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
}

updateLabel

- (void)updateLabel {

    BannerDC *bannerObj = [[BannerDC alloc] init];
    if (count == bannerList.count){
        count = 0;
    } else {
        bannerObj = [bannerList objectAtIndex:count];

        lblFeaturedEventTitle.text = bannerObj.line1;
        imgFeaturedEventImage.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:bannerObj.img_url]]];

        // get the view that's currently showing
        [self.viewBannersBackground removeFromSuperview];
        [self.viewBanners addSubview:self.viewBannersBackground];

        // set up an animation for the transition between the views
        CATransition *animation = [CATransition animation];
        [animation setDuration:1.0];
        [animation setType:kCATransitionPush];
        [animation setSubtype:kCATransitionFromRight];
        [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];

        [[self.viewBannersBackground layer] addAnimation:animation forKey:@"SwitchToView1"];

        count++;
    }
}

因此，由于计时器功能，我的主线程在动画期间卡住（或显示延迟）。我想在线程中使用这个动画，我在NSThread和NSTimer之间感到困惑，我该怎么做呢？

Answer 1

您不应该使用dataWithContentsOfURL:[下载横幅图片，因为它是同步的，您之前可能已经下载了该图片并可以重复使用。

查看更改为SDWebImage之类的异步图像管理库，它将为您处理此问题而不会阻塞主线程（因此您的计时器或动画都不会受到影响）。

Answer 2

您可以尝试：[NSTimer scheduledTimerWithTimeInterval：target：selector：userInfo：重复：]

NSThread：在后台线程中运行

NSTimer（应该在主线程中调用）：在主线程中运行

iOS - NSTimer导致在动画期间停止应用程序

2 个答案: