Iphone：如何滚动到第二部分的第一个单元格，让第一部分的标题可见

发布于 2024-10-10 05:03:02 字数 342 浏览 5 评论 0原文

我有一个包含行和部分的 UITableView。我想滚动到第二部分的第一项，让第一部分的标题可见。就像我手动滚动列表直到达到该状态一样。

---- TOP OF SCREEN ----
Header of first section
Header of the second section
cell 1
cell 2
cell 3
Header of the third section
cell 1
cell 2
...

scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1] 不做这项工作，它隐藏了第一部分的标题。

原文

I have an UITableView with rows and sections.
I would like to scroll to the first item of the second section, letting the header of the first section visible. Like if I had manually scrolled the list until reaching that state.

---- TOP OF SCREEN ----
Header of first section
Header of the second section
cell 1
cell 2
cell 3
Header of the third section
cell 1
cell 2
...

scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]
does not do the job, it hides the header of the first section.

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海夕 2024-10-17 05:03:02

我们继续前进。我根据Kevin的想法找到了这个方法。为了能够将动画设置为 YES，我使用 UIScrollView 的委托方法捕获动画的结束。有用。但任何有助于不做两个动画的解决方案将不胜感激。 知道如何做到这一点吗？

- (IBAction) scrollToToday:(BOOL)animate {
    [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:animate];
    if (animate == NO) [self showFirstHeaderLine:NO];
}

- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
    [self showFirstHeaderLine:YES];
}

- (void) showFirstHeaderLine:(BOOL)animate {
    CGRect headerRect = [self.tableView rectForHeaderInSection:1];
    CGPoint scrollPoint = headerRect.origin;
    scrollPoint.y -= headerRect.size.height;
    [self.tableView setContentOffset:scrollPoint animated:animate];
}

由于这段代码，动画设置为YES时的过程应该在scrollViewDidEndScrollingAnimation和showFirstHeaderLine之间无限循环...它循环，是的，但只循环一次...<强>知道为什么吗？

We're moving on. I found this method based on Kevin's idea. To be able to set animated to YES, I catch the end of animation using a delegate method of UIScrollView. It works. But any solution that would help not doing 2 animations would be greatly appreciated. Any idea about how to do this ?

- (IBAction) scrollToToday:(BOOL)animate {
    [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1] atScrollPosition:UITableViewScrollPositionTop animated:animate];
    if (animate == NO) [self showFirstHeaderLine:NO];
}

- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
    [self showFirstHeaderLine:YES];
}

- (void) showFirstHeaderLine:(BOOL)animate {
    CGRect headerRect = [self.tableView rectForHeaderInSection:1];
    CGPoint scrollPoint = headerRect.origin;
    scrollPoint.y -= headerRect.size.height;
    [self.tableView setContentOffset:scrollPoint animated:animate];
}

Dude to this code, the process when animated is set to YES should loop infinitely beetween scrollViewDidEndScrollingAnimation and showFirstHeaderLine... It loops, yes, but only once... Any idea about why ?

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唔猫 2024-10-17 05:03:02

您可以抓取所需行的矩形，然后减去上一节标题的高度并滚动到该点。类似以下内容（未经测试）应该有效：

CGRect rowRect = [table rectForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]];
CGRect headerRect = [table rectForHeaderInSection:0];
rowRect.origin.y -= headerRect.size.height;
rowRect.size.height += headerRect.size.height;
[table scrollRectToVisible:rowRect animated:YES]; // UITableView is a subclass of UIScrollView

You can grab the rect for the row you want, then subtract the height of the header of the previous section and scroll to that point. Something like the following (untested) should work:

CGRect rowRect = [table rectForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]];
CGRect headerRect = [table rectForHeaderInSection:0];
rowRect.origin.y -= headerRect.size.height;
rowRect.size.height += headerRect.size.height;
[table scrollRectToVisible:rowRect animated:YES]; // UITableView is a subclass of UIScrollView

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