如何使用 Swift 在 UICollectionView 中显示/隐藏单元格？

Question

I've displayed cells (0 to 9 and Ok,Cancel button) using UICollectionView.

Below is what I want:

1. The Ok and Cancel button will be hidden at first.
2. When user selects at least one number then Cancel button becomes visible.
3. When user selects total four number then Ok button also becomes visible.

Below is the code that I've done :

var items = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "Cancel","0", "OK"]

...

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

   let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! CustomCollectionViewCell

        cell.lblNumber!.text = self.items[indexPath.item]

        if (self.items[indexPath.item])=="Cancel" {
            cell.hidden = true; 
        }

        if (self.items[indexPath.item])=="OK" {
            cell.hidden = true;
        } 

        return cell
    }

 func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {

    print("You selected cell #\(indexPath.item) and value : \(self.items[indexPath.item]) count : \(counter)")
    ...
  }

How can this be achieved?

Answer 1

hi here is answer with example:

import UIKit

class ViewController: UIViewController {

    var objectNumCollectionViewCell : NumCollectionViewCell = NumCollectionViewCell()

    @IBOutlet weak var lblnumber: UILabel!
    var items = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "Cancel","0", "OK"]

    var strnum: String = ""

    @IBOutlet weak var collectionviewMain: UICollectionView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - CollectionView DataSource Method

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

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int{
        return items.count
    }

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell{
            objectNumCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! NumCollectionViewCell
            objectNumCollectionViewCell.lblNum.text = items[indexPath.item] as String

        if indexPath.item == 9 {
            if lblnumber.text?.characters.count > 0 {
                objectNumCollectionViewCell.hidden = false
            }
            else{
                objectNumCollectionViewCell.hidden = true
            }
        }
        else
        {
            objectNumCollectionViewCell.hidden = false
        }

        if indexPath.item == 11 {
            if strnum.characters.count > 3 {
              objectNumCollectionViewCell.hidden = false
            }
            else{
                objectNumCollectionViewCell.hidden = true
            }
        }

        objectNumCollectionViewCell.layer.borderWidth = 1.0
        objectNumCollectionViewCell.layer.borderColor = UIColor.darkGrayColor().CGColor
        objectNumCollectionViewCell.layer.cornerRadius = 10.0
        objectNumCollectionViewCell.layer.masksToBounds = true

        return objectNumCollectionViewCell
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets{
            return UIEdgeInsetsMake(0, 5, 0, 5);
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize{
        return CGSizeMake(self.view.frame.size.width/3-10, 100)
    }

    // MARK: - CollectionView Delegate Method

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath){

        objectNumCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! NumCollectionViewCell

        if indexPath.item == 9 {
            strnum.removeAtIndex(strnum.endIndex.predecessor())
        }
        else if indexPath.item == 11{
            let alert:UIAlertView = UIAlertView(title: "Number Demo", message: "You have Pressed Ok", delegate: nil, cancelButtonTitle: "ok")

            dispatch_async(dispatch_get_main_queue(), {
                alert.show()
            })
        }
        else
        {
            if strnum.characters.count < 4 {
                strnum.append(Character(items[indexPath.item] as String))
            }
       }

        lblnumber.text = strnum
        collectionviewMain.reloadData()
    }
}

// Custom cell class
// identifier = "cell"

import UIKit

class NumCollectionViewCell: UICollectionViewCell {

    @IBOutlet weak var lblNum: UILabel! // please declare label in storyboard

}

Answer 2

if "OK" & "CANCEL" both buttons are hidden first , you can use the textfield in which the text is printed by pressing any button . 
 if textfield.text == "" {
  okbutton.ishidden == true
  cancel button.ishdden == true
 }else if textfield.text != "" {
  okbutton.ishidden == false
  cancel button.ishdden == false
}