我正在尝试产生同样的效果，就像 instagram 在他们的标题中所做的那样。我该怎么做？

我尝试了很多解决方案。

最佳 - https://github.com/andreamazz/AMScrollingNavbar

但它有一个大问题 - 它使用 uipangesturerecognizer 移动条。这对我不利，因为如果表格位于顶部，我想显示栏。

我试图将此控件的工作更改为 ScrollView 委托(delegate)，但发现它有很多问题，您有什么想法，他们是如何做到的？

最佳答案

我找到了解决方案，就像您说的那样 - 您必须稍微弄乱 ScrollView 委托(delegate)，但大约 2 小时后我就弄清楚了。我试图解决的问题是能够像您在 Instagram 中那样以一个连续的 Action 获得标题。

因此，首先检查 xib 设置，它在 (0 20, 320 85) 处有一个标题 View ，就在 (0 20, 320 548) 处的 TableView 后面

下面是启动后的样子(黄色的表格 View 框架):

这是我希望它在下拉后的样子(红色的标题框):

所以我只粘贴带有注释的代码，我希望它足够容易理解。

定义

#define SIGNIFICANT_SCROLLING_DISTANCE 200

创建两个属性

@property (nonatomic) CGFloat lastScrollViewOffsetY;
@property (nonatomic) CGFloat distancePulledDownwards;

然后为 scrollViewDidScroll 委托(delegate)方法添加以下实现

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // store current scroll view frame as we will change it later on and set it
    // back to the scroll view in the very end
    CGRect currentScrollViewRect = scrollView.frame;
    // same with the content offset
    CGPoint currentScrollViewOffset = scrollView.contentOffset;
    CGFloat offsetShiftY = self.lastScrollViewOffsetY - scrollView.contentOffset.y;

    if (offsetShiftY > 0) {
        // pulling downwards
        // keep trrack of the distance that we pulled downwards
        self.distancePulledDownwards += offsetShiftY;

        // header opens (table view shifts its frame down) in two cases:
        // 1. contentOffset.y<0
        // 2. scrolled downwards a significant amount or header is already open
        // but in both cases we have to make sure that it doesn't open further than we want it to
        CGFloat wantedOriginY = currentScrollViewRect.origin.y;
        if ((scrollView.contentOffset.y<0) || (self.distancePulledDownwards > SIGNIFICANT_SCROLLING_DISTANCE) || (currentScrollViewRect.origin.y>20)){

            // shift scroll views frame by offset shift
            wantedOriginY = currentScrollViewRect.origin.y + offsetShiftY;
            // compensate that shift by moving content offset back
            currentScrollViewOffset.y += (wantedOriginY <= 105) ? offsetShiftY : 0;
        }
        currentScrollViewRect.origin.y = (wantedOriginY <= 105) ? wantedOriginY : 105;

    }
    else {
        // pulling upwards
        self.distancePulledDownwards = 0;

        // header closes (table view shifts its frame up) in one case: when it is open =) (and contentOffset.y>0 to eliminate closing on bounce)
        if (scrollView.contentOffset.y > 0) {
            CGFloat wantedOriginY = currentScrollViewRect.origin.y + offsetShiftY;
            currentScrollViewRect.origin.y = (wantedOriginY >= 20) ? wantedOriginY : 20;
            currentScrollViewOffset.y += (wantedOriginY >= 20) ? offsetShiftY : 0;
        }
    }

    // set the changed (if it was changed at all) frame to the scroll view
    [scrollView setFrame:currentScrollViewRect];

    // correct offset using a special trick
    // it ensures that scrollViewDidScroll: won't be called on setting the offset
    scrollView.delegate = nil;
    [scrollView setContentOffset:currentScrollViewOffset];
    scrollView.delegate = self;

    // and finally remember the current offset as the last
    self.lastScrollViewOffsetY = scrollView.contentOffset.y;
}

并享受在屏幕上来回滚动的流畅表格 =) 这也可以修改，您可以添加标题并调整标题的大小，使其与 Instagram 的标题基本相同。

关于ios - 类似 Instagram 的导航栏 (iOS 7)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20273289/