ios 设置集合视图大小。（sizeForItemAtIndexPath 函数不起作用）Swift 3
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Set collectionView size. (sizeForItemAtIndexPath function is not working) Swift 3
提问by 0ndre_
I have a tableViewand in every tableViewCellis a collectionView.
我有一个tableView并且在每个tableViewCell是一个collectionView.
I am trying to change the collectionView size with this code:
我正在尝试使用以下代码更改 collectionView 大小：
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
if collectionView.tag == 2{
return CGSize(width: 100, height: 100)
}else if collectionView.tag == 4 {
return CGSize(width: 222, height: 200)
}else{
return CGSize(width: 10, height: 10)
}
}
The problem is that there is no error but cells do not change sizes
问题是没有错误但单元格不会改变大小
If you need to know something more, just write a comment.
如果您需要了解更多信息，请写评论。
Thank you.
谢谢你。
采纳答案by 0ndre_
So This is my code right now and it works:
所以这是我现在的代码，它可以工作：
collectionView.delegate = dataSourceDelegate
collectionView.dataSource = dataSourceDelegate
collectionView.tag = row
collectionView.setContentOffset(collectionView.contentOffset, animated:false)
collectionView.reloadData()
collectionView.register(UINib(nibName: "eventsCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "eventsCollectionViewCell")
if row == 2{
let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
layout.itemSize = CGSize(width: 120, height: 120)
layout.scrollDirection = .horizontal
collectionView.collectionViewLayout = layout
}else if row == 4 {
let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
layout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
layout.itemSize = CGSize(width: 222, height: 200)
layout.scrollDirection = .horizontal
collectionView.collectionViewLayout = layout
}else{
print("else")
}
回答by Burak Dizlek
First, don't forget extends from UICollectionViewDelegateFlowLayoutdelegate.
首先，不要忘记从UICollectionViewDelegateFlowLayout委托扩展。
For single collectionview display logic :
对于单个 collectionview 显示逻辑：
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let width = ((collectionView.frame.width - 15) / 2) // 15 because of paddings
print("cell width : \(width)")
return CGSize(width: width, height: 200)
}
And important point in storyboard don't forget Estimate Size : None
故事板中的重点不要忘记估计大小：无
回答by Pedro Mancheno
The signature for this method has changed in Swift 3 to:
此方法的签名在 Swift 3 中已更改为：
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
// your code here
}
Pay attention to the subtle difference: (_ collectionView: ...instead of (collectionView: ....
注意细微的差别：(_ collectionView: ...而不是(collectionView: ...。
This is because in Swift 3, you have to explicitly specify the label of the first parameter. You can override this default behaviour by adding the underscore character _.
这是因为在 Swift 3 中，您必须明确指定第一个参数的标签。您可以通过添加下划线字符来覆盖此默认行为_。
Also, make sure that your class adopts both UICollectionViewDelegateand UICollectionViewDelegateFlowLayoutprotocols
另外，请确保您的班级同时采用UICollectionViewDelegate和UICollectionViewDelegateFlowLayout协议
class MyViewController: UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {
// your code here
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize {
// your code here
}
}
Refer to this linkto learn more about changes in Swift 3.
请参阅此链接以了解有关 Swift 3 更改的更多信息。
回答by Vikas Krishnan
You need to specify that you implement the protocol UICollectionViewDelegateFlowLayout in your class declaration.
您需要在类声明中指定实现协议 UICollectionViewDelegateFlowLayout 。
class PhrasesCompactCollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout
回答by BLC
Short Version:
短版：
Try adding
尝试添加
collectionView.delegate = dataSource
Longer version:
更长的版本：
For Me this was a small mistake -
对我来说，这是一个小错误——
collectionView.dataSource = self
This would call these methods
这将调用这些方法
func numberOfSections(in collectionView: UICollectionView) -> Int
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
However it would NOTcall
但是它不会调用
func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
sizeForItemAt indexPath: IndexPath) -> CGSize
Because this is not part of UICollectionView 's dataSource. It's part of UICollectionView's delegate.
因为这不是 UICollectionView 的数据源的一部分。它是 UICollectionView 委托的一部分。
So adding the following solved my issue.
所以添加以下内容解决了我的问题。
collectionView.delegate = dataSource
回答by t.berlin
I've had the same problem! If you make the size half the width (width/2), then it will still appear like the entire width because the padding is being added to the width/2.
我遇到了同样的问题！如果您将尺寸设为宽度的一半 (width/2)，那么它仍然会显示为整个宽度，因为填充被添加到宽度/2。
Fix: Make sure to set the section insets in Storyboard to 0. Alternatively, adjust the width/2 to a size that INCLUDES the section insets.
修复：确保将 Storyboard 中的 section insets 设置为 0。或者，将 width/2 调整为包含部分 insets 的大小。
It took me a while to fix that one ;-)
我花了一段时间来修复那个;-)
回答by Valeria
Don't forget to assign UICollectionViewFlowLayoutobject to your collectionViewLayoutsince UICollectionView uses UICollectionViewLayout (not UICollectionViewFlowLayout) by default.
不要忘记将UICollectionViewFlowLayout对象分配给collectionViewLayout，因为 UICollectionView 默认使用 UICollectionViewLayout（而不是 UICollectionView FlowLayout）。
let flowLayout = UICollectionViewFlowLayout()
collectionView.collectionViewLayout = flowLayout
让 flowLayout = UICollectionViewFlowLayout()
collectionView.collectionViewLayout = flowLayout
