uicollectionview remove top padding

问题:

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?

回答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:

回答2:

Make your Navigation Controller > NavigationBar translucent by unchecking the Translucent check box in IB > Attribute Inspector, and it will work.

回答3:

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