[英]UITableView scroll to bottom
I have this line of code:我有这行代码:
tableView.contentOffset = CGPointMake(0.0f, 10000000.0f);
The content size is a lot less than the 10000000.0f
, but the UITableView still does not scroll to the bottom.内容大小比10000000.0f
小很多,但 UITableView 仍然没有滚动到底部。 How can I do it?我该怎么做?
Scrolling to tableViewCell
?滚动到tableViewCell
?
//for instance, you have 15 cells
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:14 inSection:0];
[self.tableView scrollToRowAtIndexPath:indexPath
atScrollPosition:UITableViewScrollPositionTop
animated:YES];
You can create an extension of UIScrollView
, and use it for any instance of UIScrollView, UITableView or UICollectionView.您可以创建UIScrollView
的扩展,并将其用于 UIScrollView、UITableView 或 UICollectionView 的任何实例。
extension UIScrollView {
func scrollToBottom(animated: Bool) {
var y: CGFloat = 0.0
let HEIGHT = self.frame.size.height
if self.contentSize.height > HEIGHT {
y = self.contentSize.height - HEIGHT
}
self.setContentOffset(CGPointMake(0, y), animated: animated)
}
}
Whenever the content size if greater than scroll view's height, it will scroll accordingly to the correct position.每当内容大小大于滚动视图的高度时,它将相应地滚动到正确的位置。 This method works with AutoLayout also.此方法也适用于 AutoLayout。
UITableView
, even if there are sections with 0 elements (which will crash in every other solution I saw on the Internet) 👇这段代码非常适合UITableView
,即使有 0 个元素的部分(这会在我在互联网上看到的所有其他解决方案中崩溃)extension UITableView {
func scrollTableViewToBottom(animated: Bool) {
guard let dataSource = dataSource else { return }
var lastSectionWithAtLeasOneElements = (dataSource.numberOfSections?(in: self) ?? 1) - 1
while dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeasOneElements) < 1 {
lastSectionWithAtLeasOneElements -= 1
}
let lastRow = dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeasOneElements) - 1
guard lastSectionWithAtLeasOneElements > -1 && lastRow > -1 else { return }
let bottomIndex = IndexPath(item: lastRow, section: lastSectionWithAtLeasOneElements)
scrollToRow(at: bottomIndex, at: .bottom, animated: animated)
}
}
fixed version from Kevin in this topic, preventing infinite scroll for tableView with 0
items: Source: https://stackoverflow.com/a/59470799/9763761本主题中 Kevin 的固定版本,防止无限滚动0
项的 tableView:来源: https : //stackoverflow.com/a/59470799/9763761
func scrollToBottom(animated: Bool) {
guard let dataSource = dataSource else { return }
var lastSectionWithAtLeastOneElement = (dataSource.numberOfSections?(in: self) ?? 1) - 1
while dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeastOneElement) < 1 && lastSectionWithAtLeastOneElement > 0 {
lastSectionWithAtLeastOneElement -= 1
}
let lastRow = dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeastOneElement) - 1
guard lastSectionWithAtLeastOneElement > -1 && lastRow > -1 else { return }
let bottomIndex = IndexPath(item: lastRow, section: lastSectionWithAtLeastOneElement)
scrollToRow(at: bottomIndex, at: .bottom, animated: animated)
}
UIScrollView
, but won't work for UITableView
that have more cells then one screen can fit, because of Apple's weird internal implementation of UITableViewController
: 👇此代码为UIScrollView
,但不工作UITableView
有更多的细胞,然后在一个屏幕可以适应,因为苹果的怪异内部实现的UITableViewController
:extension UIScrollView {
func scrollToBottom(animated: Bool) {
guard contentSize.height > bounds.size.height else { return }
let bottomOffset = CGPoint(x: 0, y: contentSize.height - bounds.size.height + contentInset.bottom)
setContentOffset(bottomOffset, animated: true)
}
}
Unfortunately I don't yet have enough rep to comment, but vol's answer has 1 mistake in it which causes an infinite while loop when you call it on a tableview with 0 items, aside from that it works perfectly!不幸的是,我还没有足够的代表来发表评论,但是 vol 的回答中有 1 个错误,当您在具有 0 个项目的 tableview 上调用它时会导致无限的 while 循环,除此之外它工作得很好! Corrected code below:更正以下代码:
func scrollToBottom(animated: Bool) {
guard let dataSource = dataSource else { return }
var lastSectionWithAtLeastOneElement = (dataSource.numberOfSections?(in: self) ?? 1) - 1
while dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeastOneElement) < 1 && lastSectionWithAtLeastOneElement > 0 {
lastSectionWithAtLeastOneElement -= 1
}
let lastRow = dataSource.tableView(self, numberOfRowsInSection: lastSectionWithAtLeastOneElement) - 1
guard lastSectionWithAtLeastOneElement > -1 && lastRow > -1 else { return }
let bottomIndex = IndexPath(item: lastRow, section: lastSectionWithAtLeastOneElement)
scrollToRow(at: bottomIndex, at: .bottom, animated: animated)
}
try this code:试试这个代码:
self.tableView.reloadData()
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()+0.1, execute: {
let indexPath = IndexPath(row: self.dateSource.count-1, section: 0)
self.tableView.scrollToRow(at: indexPath, at: UITableViewScrollPosition.bottom, animated: true)
})
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