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

Question

The UICollectionView Cell photo

UICollectionView控制器的下面

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) 
} 

的代码有UICollectionView细胞

import UIKit 

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

} 

的代码有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()) 
      } 
     }) 
    } 
} 

有一个在收集很多空间tionView Cell，如何根据SWIFT3中的单词长度自动更改单元格高度？

我已经尝试了很多方法，但这些都是为tableview。

Answer 1

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

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

，然后在您的自定义单元格类

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 
} 

这里实现preferredLayoutAttributesFittingAttributes是一个教程链接详细解释的很清楚相同https://possiblemobile.com/2016/02/sizing-uicollectionviewcell-fit-multiline-uilabel/