iOS - UIScrollView不会更新其内容,并且一些UIViews在重新加载后会消失

Question

我有UITableViewController与UIScrollView内UIView作为它的头. UIScrollView用于显示图像的幻灯片:

UITableView
 -UITableViewHeaderView
   -UIView
      -UIScrollView
        -UIImageView
          ...
      -UIPageControl

每个图像都有一个带有标题和描述的子视图:

UIImageView
  -UIView
    -UILabel
    -UILabel

当我需要更新我的tableView一个委托方法被调用,它重新加载a tableView和调用addImages方法中的数据:

- (void)eventsUpdated
{
    if ([self respondsToSelector:@selector(setRefreshControl:)])
        [self.refreshControl endRefreshing];

    [self.tableView reloadData];
    [self addImages];
}

以下是我添加图片的方式:

- (void)addImages
[self.scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

    for (int i = 0; i < images.count; i++) {
        CGRect frame;
        frame.origin.x = self.scrollView.frame.size.width * i;
        frame.origin.y = 0;
        frame.size = self.scrollView.frame.size;

        UIImageView *subview = [self createImageViewForEvent:[images objectAtIndex:i] inFrame:frame];
        subview.frame = frame;
        [self.scrollView addSubview:subview];
    }

    self.scrollView.contentSize = CGSizeMake(scrollView.frame.size.width*images.count, scrollView.frame.size.height);
    pageControll.currentPage = 0;
    pageControll.numberOfPages = images.count;

}

- (UIImageView *)createImageViewForEvent:(Event *)event inFrame:(CGRect)frame
{
    UIImage *image;

    NSString *imageName = [event.imageName lastPathComponent];
    NSString *bundleFilePath = [[NSBundle mainBundle] pathForResource:[imageName stringByDeletingPathExtension] ofType:[imageName pathExtension]];

    image = [UIImage imageWithContentsOfFile:bundleFilePath];


    UIImageView *output = [[UIImageView alloc] initWithImage:image];
    output.frame = frame;

    UIView *descriptionView = [[UIView alloc] initWithFrame:CGRectMake(0, frame.size.height*0.7, frame.size.width, frame.size.height*0.3)];

    descriptionView.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.5];
    descriptionView.alpha = 1.0;

    UILabel *header = [[UILabel alloc] initWithFrame:CGRectMake(10, 5, frame.size.width-20, 12)];
    header.textColor = [UIColor colorWithRed:210/256.0 green:217/256.0 blue:231/256.0 alpha:1.0];
    header.font = [UIFont fontWithName:@"Helvetica" size:17];
    header.backgroundColor = [UIColor clearColor];
    header.lineBreakMode = UILineBreakModeTailTruncation;
    header.numberOfLines = 1;

    UILabel *description = [[UILabel alloc] initWithFrame:CGRectMake(10, 22, frame.size.width-20, 28)];
    description.textColor = [UIColor colorWithRed:255/256.0 green:255/256.0 blue:255/256.0 alpha:1.0];
    description.font = [UIFont fontWithName:@"Helvetica" size:12];
    description.backgroundColor = [UIColor clearColor];
    description.lineBreakMode = UILineBreakModeTailTruncation;
    description.numberOfLines = 2;

    header.text = event.title;
    [descriptionView addSubview:header];

    description.text = event.shortDesription;
    [descriptionView addSubview:description];

    [output addSubview:descriptionView];

    return output;
}

首次启动后一切正常,但如果我尝试重新加载tableView并addImages再次调用,所有UILabel都会消失,只有UIImageView并且UIView可见.

UPD:

我注意到的是,我的UILabel在一段时间后出现,大约在30秒后出现.我以前从未经历过类似的事情

UPD 2:

我重装我之后tableView和scrollview,scrollView's内容未更新,马上,只有后,我开始滚动

Answer 1

我从您发布的代码中复制了一个示例项目,并且没有在标签或任何其他组件上发现任何令人耳目一新的问题.这让我认为问题不在你发布的代码中,而是在其他地方.

通常当你看到这样的延迟时,是因为一些不应该并行运行的代码并行运行.

我建议你查看你打电话的方式和时间eventsUpdated.您必须确保在主线程上执行调用,并且只有在您的事件数组完成更新后才会执行.要检查,您可以添加以下行eventsUpdated:

NSLog(@"Current: %@, main: %@", [NSThread currentThread], [NSThread mainThread]);

请发布日志!:-)

我建议你也在你的问题中添加调用方法的代码eventsUpdated,因为它也可能有所帮助.