Why is UICollectionViewCell's outlet nil in Interface Builder Xcode7.1 OS X Yosemite?

Question

I have created a custom UICollectionViewCell in Interface Builder, When I run the project, the UICollectionViewCell's subViews are nil, subviews doesn't show.

I checked on the Internet, someBody say " **I am calling

self.collectionView.registerClass(YNAskQuestionTextCollectionViewCell.self, forCellWithReuseIdentifier: "Cell_Ask_Qustion_text").

If you are using a storyboard you don't want to call this. It will overwrite what you have in your storyboard.**"

Then I remove registerClass. But I get error as below

init?(coder aDecoder: NSCoder) of custom UICollectionViewCell , the error is fatal error: init(coder:) has not been implemented: file /Users/nongmeng/Desktop/nongjitong/nongjitong/class/home/conreoller/ask question/YNAskQuestionTextCollectionViewCell.swift, line 48.

If I use code to add subViews， they show,Everything works fine. I wnat know Why.Why are subViews Of UICollectionViewCell in Interface Builder nil. Anyone can help me? Here is the example project. https://github.com/chengyanan/UICollectionView

This is viewController

    //MARK: life cycle
    override func viewDidLoad() {
        super.viewDidLoad()

        self.collectionView.registerClass(YNAskQuestionTextCollectionViewCell.self, forCellWithReuseIdentifier: "Cell_Ask_Qustion_text")

        self.collectionView.registerClass(YNAskQuestionImageCollectionViewCell.self , forCellWithReuseIdentifier: "Cell_Ask_Qustion_Image")

        self.collectionView.registerClass(YNAskQuestionLocationCollectionViewCell.self , forCellWithReuseIdentifier: "Cell_Ask_Qustion_Location")

        let flow = UICollectionViewFlowLayout()

        flow.minimumInteritemSpacing = 6
        flow.minimumLineSpacing = 16

        let size = CGSizeMake(self.view.frame.size.width, 100)
        print(size)  
        flow.itemSize = size
        flow.sectionInset = UIEdgeInsetsMake(0, 0, 30, 0)
        flow.scrollDirection = UICollectionViewScrollDirection.Vertical
        self.collectionView.collectionViewLayout = flow

        self.collectionView.backgroundColor = kRGBA(234, g: 234, b: 234, a: 1)

        self.collectionView.bounces = true
    }
//MARK:UICollectionViewDataSource    
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {

        return 3
    }


    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 1
    }

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

        if indexPath.section == 0 {

            let identify = "Cell_Ask_Qustion_text"

            let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identify, forIndexPath: indexPath) as! YNAskQuestionTextCollectionViewCell

            return cell

        } else if indexPath.section == 2 {

            let identify = "Cell_Ask_Qustion_Location"

            let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identify, forIndexPath: indexPath) as! YNAskQuestionLocationCollectionViewCell

            return cell

        }


        let identify = "Cell_Ask_Qustion_Image"

        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identify, forIndexPath: indexPath) as! YNAskQuestionImageCollectionViewCell

        return cell
    }

this is custom UICollectionViewCell

import UIKit

class YNAskQuestionTextCollectionViewCell: UICollectionViewCell {

    @IBOutlet weak var textView: UITextView!

    override init(frame: CGRect) {
        super.init(frame: frame)

        self.backgroundColor = UIColor.greenColor()

    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

Answer 1

If you are using a nib file then you need to register nib file. check the below code

Change your code for registerClass to registerNib

 self.collectionView?.registerNib(UINib(nibName: "yourcellclass", bundle: nil), forCellWithReuseIdentifier: "identifier")