Question

下面的UICollectionView Controller代码

import UIKit
import Parse


class homeVC: UICollectionViewController {

// refresher variable
var refresher : UIRefreshControl!

// size of page
//var page : Int = 5

// arrays to hold server information
var uuidArray = [String]()
var contentArray = [String]()
var titleArray = [String]()


// default function
override func viewDidLoad() {
    super.viewDidLoad()

    // always vertical scroll
    self.collectionView?.alwaysBounceVertical = true

    // background color
    collectionView?.backgroundColor = .white

    // title at the top
    self.navigationItem.title = PFUser.current()?.username?.uppercased()

    // pull to refresh
    refresher = UIRefreshControl()
    refresher.addTarget(self, action: #selector(homeVC.refresh), for: UIControlEvents.valueChanged)
    collectionView?.addSubview(refresher)


    // load posts func
    loadPosts()

        }

// refreshing func
func refresh() {

    // reload posts
    loadPosts()

    // stop refresher animating
    refresher.endRefreshing()

}

    // load posts func
    func loadPosts() {

        // request infomration from server
        let query = PFQuery(className: "posts")
        query.whereKey("username", equalTo: PFUser.current()!.username!)
    //    query.limit = page
        query.findObjectsInBackground (block: { (objects, error) -> Void in
            if error == nil {

                // clean up
                self.uuidArray.removeAll(keepingCapacity: false)
                self.contentArray.removeAll(keepingCapacity: false)
                self.titleArray.removeAll(keepingCapacity: false)



                // find objects related to our request
                for object in objects! {

                    // add found data to arrays (holders)
                    self.uuidArray.append(object.object(forKey: "uuid") as! String)
                    self.contentArray.append(object.object(forKey: "content") as! String)
                    self.titleArray.append(object.object(forKey: "title") as! String)


                }

                self.collectionView?.reloadData()

            } else {
                print(error!.localizedDescription)
            }
        })

}


// cell numb
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return contentArray.count
}


// cell size
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
    let size = CGSize(width: self.view.frame.size.width / 1, height: self.view.frame.size.width / 1)
    return size
}


// cell config
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    // define cell
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! Cell

    // get content and tile from the contentArrary and titleArray to the text Label in cells
    cell.contentTxt.text = contentArray[indexPath.row]
    cell.titleTxt.text = titleArray[indexPath.row]


    return cell
}



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


// define header
let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "Header", for: indexPath) as! headerVC

    //Implement tap gestures

    // tap followings
    let bookedTap = UITapGestureRecognizer(target: self, action: #selector(homeVC.bookedTap))
    bookedTap.numberOfTapsRequired = 1
    header.booked.isUserInteractionEnabled = true
    header.booked.addGestureRecognizer(bookedTap)

// get users data with connections to columns of PFuser class
header.fullnameTxt.text = (PFUser.current()?.object(forKey: "username") as? String)?.uppercased()

let avaQuery = PFUser.current()?.object(forKey: "ava") as! PFFile
avaQuery.getDataInBackground { (data, error) -> Void in
    header.avaImg.image = UIImage(data: data!)
}
    header.button.setTitle("edit profile", for: UIControlState())

    return header
}

// tapped followings label
func bookedTap() {
    user = PFUser.current()!.username!
    category = "booked"

    // make reference to followersVC
    let followings = self.storyboard?.instantiateViewController(withIdentifier: "bookedVC") as! bookedVC

    // present
    self.navigationController?.pushViewController(followings, animated: true)
}

有UICollectionView Cell的代码

import UIKit

class Cell: UICollectionViewCell {
@IBOutlet weak var titleTxt: UILabel!
@IBOutlet weak var contentTxt: UITextView!

}

有headerVC的代码

import UIKit
import Parse

class headerVC: UICollectionReusableView {
@IBOutlet weak var avaImg: UIImageView!
@IBOutlet weak var fullnameTxt: UILabel!
@IBOutlet weak var button: UIButton!
@IBOutlet weak var booked: UIButton!

// default func
override func awakeFromNib() {
    super.awakeFromNib()

}

// clicked follow button from GuestVC
@IBAction func followBtn_clicked(_ sender: AnyObject) {

    let title = button.title(for: UIControlState())

    // to follow
    if title == "FOLLOW" {
        let object = PFObject(className: "follow")
        object["follower"] = PFUser.current()?.username
        object["following"] = guestname.last!
        object.saveInBackground(block: { (success, error) -> Void in
            if success {
                self.button.setTitle("FOLLOWING", for: UIControlState())
                self.button.backgroundColor = .green

                // send follow notification
                let newsObj = PFObject(className: "news")
                newsObj["by"] = PFUser.current()?.username
                newsObj["ava"] = PFUser.current()?.object(forKey: "ava") as! PFFile
                newsObj["to"] = guestname.last
                newsObj["owner"] = ""
                newsObj["uuid"] = ""
                newsObj["type"] = "follow"
                newsObj["checked"] = "no"
                newsObj.saveEventually()


            } else {
                print(error?.localizedDescription ?? String())
            }
        })

        // unfollow
    } else {
        let query = PFQuery(className: "follow")
        query.whereKey("follower", equalTo: PFUser.current()!.username!)
        query.whereKey("following", equalTo: guestname.last!)
        query.findObjectsInBackground(block: { (objects, error) -> Void in
            if error == nil {

                for object in objects! {
                    object.deleteInBackground(block: { (success, error) -> Void in
                        if success {
                            self.button.setTitle("FOLLOW", for: UIControlState())
                            self.button.backgroundColor = .lightGray


                            // delete follow notification
                            let newsQuery = PFQuery(className: "news")
                            newsQuery.whereKey("by", equalTo: PFUser.current()!.username!)
                            newsQuery.whereKey("to", equalTo: guestname.last!)
                            newsQuery.whereKey("type", equalTo: "follow")
                            newsQuery.findObjectsInBackground(block: { (objects, error) -> Void in
                                if error == nil {
                                    for object in objects! {
                                        object.deleteEventually()
                                    }
                                }
                            })


                        } else {
                            print(error?.localizedDescription ?? String())
                        }
                    })
                }

            } else {
                print(error?.localizedDescription ?? String())
            }
        })
    }
}

CollectionView Cell中有很多空格，如何根据SWIFT3中单词的长度自动更改单元格的高度？

我尝试了很多方法，但这些方法适用于tableview。

Answer 1

首先，您需要在UICollectionViewFlowLayout上设置estimatedItemSize。这样，当您设置estimatedItemSize属性时，Flow布局将变为动态。

self.flowLayout.estimatedItemSize = CGSize(width: 100, height: 100)

然后在自定义单元格类中实现preferredLayoutAttributesFittingAttributes

var heightCalculated: Bool = false

override func preferredLayoutAttributesFittingAttributes(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
    //store height to avoid indefinite calling.
    if !heightCalculated {
        setNeedsLayout()
        layoutIfNeeded()
        let size = contentView.systemLayoutSizeFittingSize(layoutAttributes.size)
        var newFrame = layoutAttributes.frame
        newFrame.size.width = CGFloat(ceilf(Float(size.width)))
        layoutAttributes.frame = newFrame
        heightCalculated = true
    }
    return layoutAttributes
}

这是指向教程的链接，非常清楚地详细解释https://possiblemobile.com/2016/02/sizing-uicollectionviewcell-fit-multiline-uilabel/

如何根据Swift3中的内容自动更改UICollectionView Cell的高度？

1 个答案: