uicollectionview 删除顶部填充

Question

I have a UICollectionView that is the entire view but it lives inside "view" (it is not UICollectionViewController). Adding a cell to this collection view shows it in the following order in storyboard:

This is how it looks in the emulator:

I don't understand how to get rid of that view. All the insets are at zero in Storyboard Size Inspector for collection view. Just to be sure, I also have the following code:

override func viewWillLayoutSubviews() {
    let layout = self.collectionViewProducts.collectionViewLayout as! UICollectionViewFlowLayout

    let containerWidth = UIScreen.main.bounds.size.width - 40.0
    let itemWidth = (containerWidth / 3.0)
    let itemHeight = (itemWidth / 0.75) + 30

    layout.sectionInset = UIEdgeInsets(top: 0.0, left: 0.0, bottom: 0.0, right: 0.0)

    layout.itemSize = CGSize(width: itemWidth, height: itemHeight)
}

How can I get rid of that top padding?

Answer 1

You can fix top padding issue by considering one of the following method.

Method 1 : Natural way to fix your problem by setting up your collectionView dimensions properly from StoryBoard .

Method 2 : **Updated**

You can validate collection frame in viewDidLayoutSubviews or viewWillLayoutSubviews

  override func viewDidLayoutSubviews() {
     collectionView.frame = CGRect(x: 0, y: 0, width: view.frame.width, height: view.frame.height)
}

Method 3 : You can Adjust Scroll View Insets from your StoryBoard Attributes Inspector .

Method 4 : You can fix this issue programatically by adjusting CollectionView contentInset .

collectionView.contentInset = UIEdgeInsets(top: **Any Value**, left: 0, bottom: 0, right: 0)

Output with top padding 5:

Output with top padding 44:

Output with top padding 64:

Answer 2

I think because this viewController is embedded in a navigationController. Let select this viewController in the storyboard and uncheck Adjust Scroll View Insets :

Answer 3

通过取消选中 IB > Attribute Inspector 中的Translucent复选框，使您的Navigation Controller > NavigationBar变为半透明，它将起作用。

Answer 4

There is one more way to resolve this issue and that is selecting collectionView -> scrollView Content Insets -> "Automatic" to "Never".

By default scrollView Content Insets value is Automatic. Please check the below image.

For more details check: UIScrollView.ContentInsetAdjustmentBehavior

https://developer.apple.com/documentation/uikit/uiscrollview/2902261-contentinsetadjustmentbehavior

Answer 5

I also had the same problem, and i fixed it with a way totally ridiculous solution.

My collectionView contained several sections which had no title & no item cells.

The top, bottom inset values of the section insets were 10 respectively. so each empty section charged height of 20 pixels.

I had 4 empty sections, and therefore, 80 top margins in the collection view.

Hope you check this as well if none of the above solutions works.