How to make both header and footer in collection v

问题:

How to make both header and footer in collection view in swift ?

I'm trying to combine a header and a footer together but it keep crashing, I couldn't find swift tutorial to understand it.

I don't how to return supplementary view for both rather just one .

I set them both on the storyboard (class + identifier )

 override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    //#warning Incomplete method implementation -- Return the number of sections
    return 2
}


override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    //#warning Incomplete method implementation -- Return the number of items in the section
    return 10
}




override func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
    var header: headerCell!
    var footer: footerCell!



    if kind == UICollectionElementKindSectionHeader {
        header =
            collectionView.dequeueReusableSupplementaryViewOfKind(kind,
                withReuseIdentifier: "header", forIndexPath: indexPath)
            as? headerCell

}
    return header

}

Error: UICollectionElementKindCell with identifier one - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> profileCC {
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("one", forIndexPath: indexPath) as! profileCC

    // Configure the cell

    return cell
}



override func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {

    switch kind {

    case UICollectionElementKindSectionHeader:

        let headerView = collectionView.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: "header", forIndexPath: indexPath) as! headerCell

        headerView.backgroundColor = UIColor.blueColor();
        return headerView

    case UICollectionElementKindSectionFooter:
        let footerView = collectionView.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: "footer", forIndexPath: indexPath) as! footerCell

        footerView.backgroundColor = UIColor.greenColor();
        return footerView

    default:

        assert(false, "Unexpected element kind")
    }
}

I hope someone will help.

回答1:

You can make an UICollectionViewController to handle the UICollectionView and in Interface Builder activate the Footer and Header sections, then you can use the following method for preview in you UICollectionView the two sections added :

override func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {

    switch kind {

    case UICollectionView.elementKindSectionHeader:

        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "Header", for: indexPath)

        headerView.backgroundColor = UIColor.blue
        return headerView

    case UICollectionView.elementKindSectionFooter:
        let footerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "Footer", for: indexPath)

        footerView.backgroundColor = UIColor.green
        return footerView

    default:

        assert(false, "Unexpected element kind")
    }

In the above code I put the identifier for the footer and header as Header and Footer for example, you can do it as you want. If you want to create a custom header or footer then you need to create a subclass of UICollectionReusableView for each and customize it as you want.

You can register your custom footer and header classes in Interface Builder or in code in the following way:

registerClass(myFooterViewClass, forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier: "myFooterView")

回答2:

Updated for Swift 3+

Step 1:

In your view controller class, register the class to be used as a header, footer, or both:

let collectionViewHeaderFooterReuseIdentifier = "MyHeaderFooterClass"

Step 2:

If using a xib, use:

collectionView.register(UINib(nibName: collectionViewHeaderFooterReuseIdentifier bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier:collectionViewHeaderFooterReuseIdentifier)

collectionView.register(UINib(nibName: collectionViewHeaderFooterReuseIdentifier bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier:collectionViewHeaderFooterReuseIdentifier)

If not using a xib:

collectionView.register(MyHeaderFooterClass.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: collectionViewHeaderFooterReuseIdentifier)

collectionView.register(MyHeaderFooterClass.self, forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier: collectionViewHeaderFooterReuseIdentifier)

Step 3:

Create a custom header/footer class, implementation looks like:

import UIKit

class MyHeaderFooterClass: UICollectionReusableView {

 override init(frame: CGRect) {
    super.init(frame: frame)
    self.backgroundColor = UIColor.purple

    // Customize here

 }

 required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)

 }
}

Step 4: If not using a xib, ignore

• Create a new empty xib: "File --> New File --> Empty".

• Name it the exact same name as the class. In this example: "MyHeaderFooterClass"

• Add a collection reusable view to the xib.
• Click on that object, select the Identity Inspector and change the class of that object to "MyHeaderFooterClass".

Step 5: - Support that new cell in your collection view via delegate method:

 func collectionView(_ collectionView: UICollectionView,
                    viewForSupplementaryElementOfKind kind: String,
                    at indexPath: IndexPath) -> UICollectionReusableView {

    switch kind {

    case UICollectionElementKindSectionHeader:
        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: collectionViewHeaderFooterReuseIdentifier, for: indexPath)

        headerView.backgroundColor = UIColor.blue
        return headerView

    case UICollectionElementKindSectionFooter:
        let footerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: collectionViewHeaderFooterReuseIdentifier, for: indexPath)

        footerView.backgroundColor = UIColor.green
        return footerView

    default:
        assert(false, "Unexpected element kind")
    }
}

回答3:

Just to complement the remaining answers, don't forget to allocate space for your header/footer views, otherwise collectionView:viewForSupplementaryElementOfKind:atIndexPath won't be called.

Do so by implementing collectionView:layout:referenceSizeForHeaderInSection in your collectionView datasource.

回答4:

Solution

class CustomFlowLayout: UICollectionViewFlowLayout {

    override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
        let attributesForElementsInRect = super.layoutAttributesForElements(in: rect)
        var newAttributesForElementsInRect = [UICollectionViewLayoutAttributes]()

        for attributes in attributesForElementsInRect! {

            if !(attributes.representedElementKind == UICollectionElementKindSectionHeader
                || attributes.representedElementKind == UICollectionElementKindSectionFooter) {

                // cells will be customise here, but Header and Footer will have layout without changes.
            }

            newAttributesForElementsInRect.append(attributes)
        }

        return newAttributesForElementsInRect
    }
}


class YourViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let headerNib = UINib.init(nibName: "HeaderCell", bundle: nil)
        collectionView.register(headerNib, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "HeaderCell")

        let footerNib = UINib.init(nibName: "FooterCell", bundle: nil)
        collectionView.register(footerNib, forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier: "FooterCell")
    }


    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

        switch kind {
        case UICollectionElementKindSectionHeader:
            let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "HeaderCell", for: indexPath) as! HeaderCell
            return headerView
        case UICollectionElementKindSectionFooter:
            let footerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "FooterCell", for: indexPath) as! FooterCell
            return footerView
        default:
            return UICollectionReusableView()
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 45)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 25)
    }
}

回答5:

After using @mobilecat code you should use this function to make the header and footer appear

 func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 180.0)
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        return CGSize(width: 60.0, height: 30.0)
    }