将数据从 Collectionview 传递到 UIcollectionResuableview

Question

我有一个集合视图，数据(字符串(在加载时从另一个VC传递到该集合视图。现在，当我想将此数据(字符串(传递给UICollectionReusabelView时。我正在执行以下步骤

收藏视图VC：

class PhotoDetailVC: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, PDHeaderViewDelegate {

// Following variables are the ones to which the data is passed to. 
var image : String!
var user: User!
var post: Posts!

@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLoad() {
    super.viewDidLoad()
    print(post.imageURL)
    collectionView.delegate = self
    collectionView.dataSource = self
    setupCells()
    increaseView()
}

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "mainImage", for: indexPath) as! PDHeader
    // I am setting the ReusableView properties through this section. Instead I just want to pass them to the header and then do stuff over there.
    header.post = self.post
    header.lol = post.postauthor
    header.label.text = post.caption
    header.label.sizeToFit()
    header.delegate = self
    let ref = URL(string: post.imageURL)
    Nuke.loadImage(with: ref!, into: header.mainPic)
    imageInHeaderForAuthor(author: post.postauthor, view: header.profilePic)
    return header
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
    let size = CGSize(width: collectionView.frame.width, height: collectionView.frame.height - 15)
    return size
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let width = (collectionView.bounds.size.width/3) - 1
    let size = CGSize(width: width, height: width)
    return size
}
func collectionView(_ collectionView: UICollectionView,
                    layout collectionViewLayout: UICollectionViewLayout,
                    minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
    return 1.0
}
func collectionView(_ collectionView: UICollectionView, layout
    collectionViewLayout: UICollectionViewLayout,
                    minimumLineSpacingForSectionAt section: Int) -> CGFloat {
    return 1.0
}

func imageInHeaderForAuthor(author: String, view: UIImageView){
    FBDataservice.ds.REF_USERS.child(author).observeSingleEvent(of: .value, with: { (snapshot) in
        if let allData = snapshot.value as? Dictionary<String, Any> {
            if let cred = allData["credentials"] as? Dictionary<String, Any> {
                let postuser = User(userid: author, userData: cred)
                if postuser.userPic != nil {
                    let req = URL(string: postuser.userPic)
                    Nuke.loadImage(with: req!, into: view)
                }
            }
        }
    })
}
}

可重用视图：

class PDHeader: UICollectionReusableView, FloatyDelegate {
@IBOutlet weak var label: UILabel!
@IBOutlet weak var mainPic: UIImageView!
@IBOutlet weak var profilePic: UIImageView!
var image : String!
var post: Posts!
var lol: String!
var floaty = Floaty()
var isOwner : Bool!
var delegate: PDHeaderViewDelegate!

override func awakeFromNib() {
    super.awakeFromNib()
    //This returns nil every time.
    print(post.postauthor)
    layoutFAB()
    profilePic.makeCircle()
    label.addDropShadow(opacity: 3, radius: 8)
}


func setDelegate(delegate: PDHeaderViewDelegate) {
    self.delegate = delegate
}
func layoutFAB() {
    floaty.openAnimationType = .pop
    floaty.buttonImage = UIImage(named: "options")
    floaty.addItem("Report", icon: UIImage(named: "trash")) { item in
        self.delegate.fabReportClicked()
    }
    if isOwner{
        floaty.addItem("Edit Profile", icon: UIImage(named: "edit")) { item in
            self.delegate.fabEditClicked()
        }
        floaty.addItem("Delete", icon: UIImage(named: "trash")) { item in
            self.delegate.fabDeleteButton()
        }
    }
    floaty.fabDelegate = self
    floaty.buttonColor = UIColor.white
    floaty.hasShadow = true
    floaty.size = 45
    addSubview(floaty)
}
}

我已经用问题注释了代码。TL;DR - 集合不会将数据传递到标头，因此我必须从viewForSupplementaryElementOfKind设置它们。

这里的实际问题是什么？标头是否在将数据传递给它之前加载？如果没有，我该如何解决此问题？

Answer 1

如果我理解了，你可以尝试使用这个选项：

class PDHeader: UICollectionReusableView, FloatyDelegate {
    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var mainPic: UIImageView!
    @IBOutlet weak var profilePic: UIImageView!
    var image : String!
    var lol: String!
    var floaty = Floaty()
    var isOwner : Bool!
    var delegate: PDHeaderViewDelegate!
    var post: Posts!{
        didSet {
           lol = post.postauthor
           label.text = post.caption
           // etc ...
        }

然后：

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "mainImage", for: indexPath) as! PDHeader
    header.post = self.post
    header.delegate = self
    return header
}