Back button on UICollectionView - swift

Question

I am trying to add a back/ return button to my UICollectionView, I have this code so far to implement the button:
import UIKit
class EmojiPopup: UIView,UICollectionViewDataSource,UICollectionViewDelegate
{
var collocationView : UICollectionView!
var arrImagesList:NSMutableArray!
var blur:UIBlurEffect = UIBlurEffect()
override init(frame: CGRect)
{
super.init(frame: frame)
arrImagesList = NSMutableArray()
self.backgroundColor = UIColor.purpleColor().colorWithAlphaComponent(0.2)
let layout = UICollectionViewFlowLayout()
//header gap
layout.headerReferenceSize = CGSizeMake(20,20)
//collection view item size
layout.itemSize = CGSizeMake(70, 70)
layout.minimumInteritemSpacing = 25
layout.minimumLineSpacing = 25
collocationView = UICollectionView(frame: CGRectMake(50,50,UIScreen.mainScreen().bounds.screenWidth - 100,UIScreen.mainScreen().bounds.screenHeight - 100), collectionViewLayout: layout)
self.addSubview(collocationView)
// Create the blurEffect and apply to view
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.ExtraLight)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.alpha = 0.7
blurEffectView.frame = self.bounds
self.addSubview(blurEffectView)
collocationView.backgroundColor = UIColor.purpleColor().colorWithAlphaComponent(0.002)
collocationView.dataSource = self
collocationView.delegate = self
collocationView.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "cellIdentifier")
//hide scrollbar
self.collocationView.showsVerticalScrollIndicator = false
//back button
let btnBack = UIButton(frame:TCRectMake(x:138 ,y:523,width:45,height:45))
btnBack.setImage(UIImage(named:"back"), forState: UIControlState.Normal)
btnBack.addTarget(self, action:"btnBackClick", forControlEvents: UIControlEvents.TouchUpInside)
self.addSubview(btnBack)
//back button func
func btnBackClick()
{
}
let fm = NSFileManager.defaultManager()
let path = NSBundle.mainBundle().resourcePath!
let items = try! fm.contentsOfDirectoryAtPath(path)
for item in items
{
if item.hasSuffix("png") && item.containsString("#") == false && item.containsString("AppIcon") == false && item.containsString("tick_blue") == false && item.containsString("video_camera") == false
{
arrImagesList.addObject(item)
}
}
}
var completeHandler:((String)->())?
func showDetails(viewParent:UIView,doneButtonClick:((String)->())?)
{
completeHandler = doneButtonClick
viewParent.addSubview(self)
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
return arrImagesList.count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
let identifier="ImageCell\(indexPath.section)\(indexPath.row)"
collectionView.registerClass(ImageViewCell.self, forCellWithReuseIdentifier:identifier)
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(identifier, forIndexPath: indexPath) as! ImageViewCell
cell.backgroundColor = UIColor(white:1, alpha:0)
cell.imgView.image = UIImage(named:arrImagesList[indexPath.row] as! String)
cell.imgView.backgroundColor = UIColor.clearColor()
cell.imgView.opaque = false
cell.imgView.contentMode = .ScaleAspectFit
//keeps blur to background
self.bringSubviewToFront(collocationView)
return cell
}
// func collectionView(collectionView: UICollectionView,
// layout collectionViewLayout: UICollectionViewLayout,
// sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
// {
// let width=UIScreen.mainScreen().bounds.size.width-50
// return CGSize(width:width/3, height:width/3)
// }
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath)
{
//let cell=collectionView.cellForItemAtIndexPath(indexPath) as! ImageViewCell
UIView.animateWithDuration(0.3, animations:{
self.collocationView.alpha=0
}, completion: { finished in
if self.completeHandler != nil
{
self.completeHandler!(self.arrImagesList[indexPath.row] as! String)
}
self.removeFromSuperview()
})
}
func showDetails(viewParent:UIView,dictData : [String:String],index:Int,doneButtonClick:(()->())?,cancelBUttonClick:(()->())?)
{
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I want the collection view to be closed if the user presses the back button, but I am not sure what to enter in the back button function. I want the user to be returned back to the main view controller (mapview) if possible

Answer 1

I will assume you are talking about a UICollectionViewController and not about a UICollectionView. A UICollectionViewController has a UICollectionView inside. You can "close" (dismiss) a UICollectionViewController but not a UICollectionView. You can even dismiss a UIViewController that has a UICollectionView inside.
You have two options:
Put you collection view controller (and the main view controller) inside a navigation controller so you can use the default back button already implemented by the navigation controller.
You can present the collection view controller modally from the main view controller. Then you need to add a close button (Not back button) that dismiss the controller (The main view controller will stay "behind" so when you dismiss the UICollectionViewController it will become visible again.
It's a long way. I suggest you read this getting started guide from Apple, there you can figure it out how navigation controllers and what they do. This is something you need to learn when developing with Swift. I suggest you go further and read the whole tutorial. After reading that chapter you should understand the navigation flow of an iOS application and implement the back-button navigation.
If you find any trouble following that tutorial, let me know.