Question

这是我第一次使用集合视图，我正在努力奋斗。我在“setupView”函数中设置了一个集合视图布局，然后实现了典型的视图方法，如numberOfSections和cellForRowAtIndexPath。现在，我只是想让集合视图工作，所以我只是使用我工作区中已有的图像，而不是从API获取图片（稍后会出现）。

这是我正在使用的代码。为什么它不显示黑屏以外的任何东西？

import UIKit
import Alamofire
import AlamofireImage

class PhotoBrowserCollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

let goldenWordsYellow = UIColor(red: 247.00/255.0, green: 192.00/255.0, blue: 51.00/255.0, alpha: 0.5)

@IBOutlet weak var menuButton:UIBarButtonItem!

@IBOutlet var picturesCollectionView: UICollectionView!

var pictureObjects = NSMutableOrderedSet(capacity: 1000)

var customRefreshControl = UIRefreshControl()

let PhotoBrowserCellIdentifier = "PhotoBrowserCell"

var dateFormatter = NSDateFormatter()

var nodeIDArray = NSMutableArray()

var timeStampDateString : String!

override func viewDidLoad() {
    super.viewDidLoad()

    self.collectionView!.registerClass(PhotoBrowserCollectionViewCell.self, forCellWithReuseIdentifier: PhotoBrowserCellIdentifier)

    self.revealViewController().rearViewRevealWidth = 280

    collectionView!.delegate = self
    collectionView!.dataSource = self

    customRefreshControl = UIRefreshControl()
    customRefreshControl.backgroundColor = goldenWordsYellow
    customRefreshControl.tintColor = UIColor.whiteColor()
    self.picturesCollectionView!.addSubview(customRefreshControl)

    navigationController?.setNavigationBarHidden(false, animated: true)
    navigationItem.title = "Pictures"


    setupView()

    populatePhotos()

    self.dateFormatter.dateFormat = "dd/MM/yy"

}


override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return 1
}

override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 5 // setting an arbitrary value in case pictureObjects is not getting correctly populated
}

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(PhotoBrowserCellIdentifier, forIndexPath: indexPath) as! PhotoBrowserCollectionViewCell

    cell.imageView.image = UIImage(named: "mail")

    return cell
}

这是我的setupView功能。

   override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
    performSegueWithIdentifier("ShowPhoto", sender: (self.pictureObjects.objectAtIndex(indexPath.item) as! PictureElement).imageURL)
}

func setupView() {
    navigationController?.setNavigationBarHidden(false, animated: true)

    let layout = UICollectionViewFlowLayout()
    let itemWidth = (view.bounds.size.width - 2) / 3
    layout.itemSize = CGSize(width: itemWidth, height: itemWidth)
    layout.minimumInteritemSpacing = 1.0
    layout.minimumLineSpacing = 1.0

    collectionView!.collectionViewLayout = layout

    navigationItem.title = "Pictures"

    customRefreshControl.tintColor = UIColor.whiteColor()
    customRefreshControl.addTarget(self, action: "handleRefresh", forControlEvents: .ValueChanged)
    self.collectionView!.addSubview(customRefreshControl)
}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    return CGSizeMake(120, 120)
}

故事板中的所有内容都显得格格不入。我正在使用UICollectionViewController swift类（不是UIViewController + collectionView组合），我真的不知道我应该使用哪些插座。这是我在整个视图控制器上的连接列表：

最后，这是我非常简单的视图层次结构。

我真的不知道为什么集合视图无法正常工作。有什么想法吗？

编辑1：我更改了很多代码并最终让我的collectionView工作。对于那些正在努力解决类似问题的人来说，这里是我为collectionView使用的全部代码。也许它可以帮助您修复自己的集合中的问题查看代码

import UIKit
import Alamofire
import AlamofireImage

class PhotoBrowserCollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

let goldenWordsYellow = UIColor(red: 247.00/255.0, green: 192.00/255.0, blue: 51.00/255.0, alpha: 0.5)

@IBOutlet weak var menuButton:UIBarButtonItem!

@IBOutlet var picturesCollectionView: UICollectionView!

var temporaryPictureObjects = NSMutableOrderedSet(capacity: 1000)
var pictureObjects = NSMutableOrderedSet(capacity: 1000)

var goldenWordsRefreshControl = UIRefreshControl()

var revealViewControllerIndicator : Int = 0

let imageCache = NSCache()

var customView: UIView!

var labelsArray: [UILabel] = []

var isAnimating = false

var currentColorIndex = 0

var currentLabelIndex = 0

var timer : NSTimer!

var populatingPhotos = false

var currentPage = 0

let PhotoBrowserCellIdentifier = "PhotoBrowserCell"

var dateFormatter = NSDateFormatter()

var nodeIDArray = NSMutableArray()

var timeStampDateString : String!

var cellLoadingIndicator = UIActivityIndicatorView()

var scrollViewDidScrollLoadingIndicator = UIActivityIndicatorView()

override func viewDidLoad() {
    super.viewDidLoad()

    self.collectionView!.registerClass(PhotoBrowserCollectionViewCell.self, forCellWithReuseIdentifier: PhotoBrowserCellIdentifier)

    self.cellLoadingIndicator.backgroundColor = goldenWordsYellow
    self.cellLoadingIndicator.hidesWhenStopped = true

if self.revealViewController() != nil {
    revealViewControllerIndicator = 1
    menuButton.target = self.revealViewController()
    menuButton.action = "revealToggle:"
    self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
    }

    self.revealViewController().rearViewRevealWidth = 280

    collectionView!.delegate = self
    collectionView!.dataSource = self

    goldenWordsRefreshControl = UIRefreshControl()
    goldenWordsRefreshControl.backgroundColor = goldenWordsYellow
    goldenWordsRefreshControl.tintColor = UIColor.whiteColor()
    self.collectionView!.addSubview(goldenWordsRefreshControl)

    navigationController?.setNavigationBarHidden(false, animated: true)
    navigationItem.title = "Pictures"

    setupView()

    populatePhotos()

    self.dateFormatter.dateFormat = "dd/MM/yy"

    self.cellLoadingIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.Gray
    self.cellLoadingIndicator.color = goldenWordsYellow
    self.cellLoadingIndicator.center = (self.collectionView?.center)!
    self.collectionView!.addSubview(cellLoadingIndicator)
    self.collectionView!.bringSubviewToFront(cellLoadingIndicator)


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

override func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
    if goldenWordsRefreshControl.refreshing {
        if !isAnimating {
            holdRefreshControl()
        }
    }
}

func holdRefreshControl() {
    timer = NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: "handleRefresh", userInfo: nil, repeats: true)
}

override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return 1
}

override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return (pictureObjects.count) // setting an arbitrary value in case pictureObjects is not getting correctly populated
}

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(PhotoBrowserCellIdentifier, forIndexPath: indexPath) as! PhotoBrowserCollectionViewCell

    if let pictureObject = pictureObjects.objectAtIndex(indexPath.row) as? PictureElement {

        let title = pictureObject.title ?? "" // if pictureObject.title == nil, then we return an empty string

        let timeStampDateObject = NSDate(timeIntervalSince1970: NSTimeInterval(pictureObject.timeStamp))
        let timeStampDateString = dateFormatter.stringFromDate(timeStampDateObject)

        let author = pictureObject.author ?? ""

        let issueNumber = pictureObject.issueNumber ?? ""
        let volumeNumber = pictureObject.volumeNumber ?? ""

        let nodeID = pictureObject.nodeID ?? 0

        let imageURL = pictureObject.imageURL ?? "http://goldenwords.ca/sites/all/themes/custom/gw/logo.png"

        cell.request?.cancel()

        if let image = self.imageCache.objectForKey(imageURL) as? UIImage {

            cell.imageView.image = image

        } else {

            cell.imageView.image = nil
            cell.request = Alamofire.request(.GET, imageURL).responseImage() { response in
                if let image = response.result.value {

                    self.imageCache.setObject(response.result.value!, forKey: imageURL)
                    if cell.imageView.image == nil {
                        cell.imageView.image = image
                    }
                }
            }
        }
    }

    return cell
}




    self.performSegueWithIdentifier("ShowPhoto", sender: self)
}

func setupView() {
    navigationController?.setNavigationBarHidden(false, animated: true)

    let layout = UICollectionViewFlowLayout()
    let itemWidth = (view.bounds.size.width) / 3
    layout.itemSize = CGSize(width: itemWidth, height: itemWidth)
    layout.minimumInteritemSpacing = 1.0
    layout.minimumLineSpacing = 1.0

    collectionView!.collectionViewLayout = layout

    navigationItem.title = "Pictures"

}

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    return CGSizeMake(((self.collectionView?.frame.width)!*0.5)-2, self.collectionView!.frame.height/3)
}




override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "ShowPhoto" {

        let detailViewController = segue.destinationViewController as! PhotoViewerViewController
        let indexPaths = self.collectionView!.indexPathsForSelectedItems()
        let indexPath = indexPaths![0] as! NSIndexPath

        let item = indexPath.item

    }
}

override func scrollViewDidScroll(scrollView: UIScrollView) {
    if (scrollView.contentOffset.y + view.frame.size.height > scrollView.contentSize.height * 0.75) {
        populatePhotos()
    }
}

func populatePhotos() {

    if populatingPhotos {
        return
    }
    populatingPhotos = true

    self.cellLoadingIndicator.startAnimating()
    self.temporaryPictureObjects.removeAllObjects()

    Alamofire.request(GWNetworking.Router.Pictures(self.currentPage)).responseJSON() { response in
        if let JSON = response.result.value {

        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)) {

            var nodeIDArray : [Int]

            if (JSON .isKindOfClass(NSDictionary)) {

                for node in JSON as! Dictionary<String, AnyObject> {

                    let nodeIDValue = node.0
                    var lastItem : Int = 0

                    self.nodeIDArray.addObject(nodeIDValue)

                    if let pictureElement : PictureElement = PictureElement(title: "Picture", nodeID: 0, timeStamp: 0, imageURL: "http://goldenwords.ca/sites/all/themes/custom/gw/logo.png", author: "Staff", issueNumber: "Issue # error", volumeNumber: "Volume # error") {

                        pictureElement.title = node.1["title"] as! String
                        pictureElement.nodeID = Int(nodeIDValue)!

                        let timeStampString = node.1["revision_timestamp"] as! String
                        pictureElement.timeStamp = Int(timeStampString)!

                        if let imageURL = node.1["image_url"] as? String {
                            pictureElement.imageURL = imageURL
                        }

                        if let author = node.1["author"] as? String {
                            pictureElement.author = author
                        }

                        if let issueNumber = node.1["issue_int"] as? String {
                            pictureElement.issueNumber = issueNumber
                        }

                        if let volumeNumber = node.1["volume_int"] as? String {
                            pictureElement.volumeNumber = volumeNumber
                        }

                        if self.pictureObjects.containsObject(pictureElement) {
                            // do not add the pictureElement to the set of pictures
                        } else {
                        lastItem = self.temporaryPictureObjects.count // Using a temporary set to not handle the dataSource set directly (safer).
                        self.temporaryPictureObjects.addObject(pictureElement)
                        }

                        let indexPaths = (lastItem..<self.temporaryPictureObjects.count).map { NSIndexPath(forItem: $0, inSection: 0) }
                    }

                }

                let timeStampSortDescriptor = NSSortDescriptor(key: "timeStamp", ascending: false)
                self.temporaryPictureObjects.sortUsingDescriptors([timeStampSortDescriptor])

            }
            dispatch_async(dispatch_get_main_queue()) {

                for object in self.temporaryPictureObjects {
                    self.pictureObjects.addObject(object)
                }

                self.temporaryPictureObjects.removeAllObjects()

                self.collectionView!.reloadData()
                self.cellLoadingIndicator.stopAnimating()
                self.goldenWordsRefreshControl.endRefreshing()

                self.currentPage++
                self.populatingPhotos = false
            }
        }
    }
}
}



func handleRefresh() {

    goldenWordsRefreshControl.beginRefreshing()

    self.pictureObjects.removeAllObjects()
    self.temporaryPictureObjects.removeAllObjects()

    self.collectionView!.reloadData()

    self.currentPage = 0

    self.picturesCollectionView.bringSubviewToFront(cellLoadingIndicator)

    self.populatingPhotos = false
    populatePhotos()

}
}

Answer 1

在格式化数据后，只需重新加载collectionView即可。的 picturesCollectionView.reloadData（）

override func viewDidLoad() { super.viewDidLoad() self.collectionView!.registerClass(PhotoBrowserCollectionViewCell.self, forCellWithReuseIdentifier: PhotoBrowserCellIdentifier) self.revealViewController().rearViewRevealWidth = 280 collectionView!.delegate = self collectionView!.dataSource = self customRefreshControl = UIRefreshControl() customRefreshControl.backgroundColor = goldenWordsYellow customRefreshControl.tintColor = UIColor.whiteColor() self.picturesCollectionView!.addSubview(customRefreshControl) navigationController?.setNavigationBarHidden(false, animated: true) navigationItem.title = "Pictures" setupView() populatePhotos() self.dateFormatter.dateFormat = "dd/MM/yy" picturesCollectionView.reloadData() }

集合视图单元格没有出现在集合视图中？

1 个答案: