ios – Tweetbot横幅图像下拉缩放图像

适用于iOS的Tweetbot和Kickstarter在具有横幅图像的用户配置文件上使用了很酷的功能.如果您向下拉桌子,则图像会缩放.

我使用以下部分工作,它改变了图像的高度,但奇怪的是,不是宽度：

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

    UIImageView *imageView = (UIImageView *)self.tableView.tableHeaderView;
    CGFloat y = -scrollView.contentOffset.y;
    imageView.frame = CGRectMake(0,scrollView.contentOffset.y,self.cachedImageViewSize.size.width+y,self.cachedImageViewSize.size.height+y);
    NSLog(@"%@",NsstringFromCGRect(imageView.frame));

}

有谁知道如何重现这种效果？

解决方法

好的,我明白了.这是我做的：

- (void)viewDidLoad {
    [super viewDidLoad];

    self.imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"church-welcome.png"]];
    self.imageView.contentMode = UIViewContentModeScaleAspectFill;
    self.cachedImageViewSize = self.imageView.frame;
    [self.tableView addSubview:self.imageView];
    [self.tableView sendSubviewToBack:self.imageView];
    self.tableView.tableHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0,self.view.frame.size.width,170)];

}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

    CGFloat y = -scrollView.contentOffset.y;
    if (y > 0) {
        self.imageView.frame = CGRectMake(0,self.cachedImageViewSize.size.height+y);
        self.imageView.center = CGPointMake(self.view.center.x,self.imageView.center.y);
    }

}