Swift: How to use "didSelectItemAtIndexPath" in UITableViewController(contains UICollectionView)? - ios

Question

I have a UITableViewController, inside the TableViewCell, it's a UICollectionView. I want to pass the data from the CollectionViewCell to a DetailViewController when user tapped the cell. I dragged a segue from the CollectionViewCell to the DetailViewController, and used the didSelectItemAtIndexPath inside the TableViewCell( which contains CollectionView), and it works.
class TableViewCell: UITableViewCell, UICollectionViewDataSource, UICollectionViewDelegate {
var posts1: [Posts] = [Posts]()
var posts2: [Posts] = [Posts]()
var categories: [Category] = [Category]()
var selectedPost1: Posts?
#IBOutlet weak var theCollectionView: UICollectionView!
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return posts1.count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let collectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionViewCell", forIndexPath: indexPath) as! CollectionViewCell
let imageUrlString: String = posts1[indexPath.row].postThumbnailUrlString
let imageUrl: NSURL = NSURL(string: imageUrlString)!
//Give Images A round cornor
let filter = AspectScaledToFillSizeWithRoundedCornersFilter(
size: collectionViewCell.postImageView.frame.size,
radius: 20.0
)
collectionViewCell.postImageView.af_setImageWithURL(imageUrl, filter: filter)
collectionViewCell.postTitleLabel.text = posts1[indexPath.row].postTite
return collectionViewCell
}
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
print("selected")
self.selectedPost1 = self.posts1[indexPath.row]
}
it can print "selected" which means the data have already been stored in self.selectedPost1. But I can't use prepareForSegue inside this class, since it can only be used in ViewController. someone told me to implement UICollectionViewDelegate in my HomeTableViewController, and call the function didSelectedItemAtIndexPath in the HomeTableViewController, like this:
import UIKit
class HomePageTableViewController: UITableViewController,UICollectionViewDelegate {
let sections: NSArray = ["latest news", "good news"]
var posts1: [Posts] = [Posts]()
var selectedIndexPath: NSIndexPath?
override func viewDidLoad() {
super.viewDidLoad()
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
if section < sections.count{
return sections[section] as? String
}
return nil
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return sections.count
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if indexPath.row == 0 && indexPath.section == 0 {
let tableViewCell = tableView.dequeueReusableCellWithIdentifier("TableViewCell") as! TableViewCell
tableViewCell.getCategories()
// tableViewCell.scrollToNextCell()
// tableViewCell.startTimer()
return tableViewCell
}
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
self.performSegueWithIdentifier("goToDetail", sender: TableViewCell())
print("selected")
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let tableViewCell1 = sender as? TableViewCell,
let postDetailPage = segue.destinationViewController as? DetailViewController{
let selectedPosts = tableViewCell1.selectedPost1
postDetailPage.selectedPost?.selectedPost1 = selectedPosts
}
However, the didSelectedItemAtIndexPath can't be called, there is no print. I don't know why?
here is my DetailViewController:
import UIKit
class DetailViewController: UIViewController {
#IBOutlet weak var postImageView: UIImageView!
var posts: [Posts] = [Posts]()
var selectedPost: TableViewCell?
override func viewDidLoad() {
super.viewDidLoad()
if let post = selectedPost?.selectedPost1{
let thumbnailUrlString = post.postThumbnailUrlString
let imageUrl: NSURL = NSURL(string: thumbnailUrlString)!
print(thumbnailUrlString)
postImageView.af_setImageWithURL(imageUrl)
}
}
and also do I need to implement in viewDidLoad or viewDidAppear?
I have been struggled in this problem for few days? need some suggestions on How to do Segue from a UICollectionViewCell (which is inside a UITableViewCell) to a new UIViewController.

Answer 1

The way you are going is correct, but you are creating one mistake.Try to implement UICollectionViewDelegate method didSelectItemAtIndexPath also inside TableViewCell and remove it from the HomePageTableViewController.
Now declare one protocol, after that create its instance inside TableViewCell and implement the protocol in the HomePageTableViewController, after that in the didSelectItemAtIndexPath use that delegate instance to call the method like this.
protocol PostDelegate {
func selectedPost(post: Posts)
}
Now create its instance inside TableViewCell and call this delegate method in the didSelectItemAtIndexPath.
class TableViewCell: UITableViewCell, UICollectionViewDataSource, UICollectionViewDelegate {
var posts1: [Posts] = [Posts]()
var posts2: [Posts] = [Posts]()
var categories: [Category] = [Category]()
var selectedPost1: Posts?
var postDelegate: PostDelegate?
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
postDelegate?. selectedPost(self.posts1[indexPath.row])
}
}
Now implement this PostDelegate protocol inside HomePageTableViewController
class HomePageTableViewController: UITableViewController,UICollectionViewDelegate {
//Your code
func selectedPost(post: Posts) {
//You will get your post object here, do what you want now
}
}
Note: Inside cellForRowAtIndexPath don't forgot to set the delegate of postDelgate with your HomePageTableViewController like this
tableViewCell.postDelegate = self
Edit:
func selectedPost(post: Posts) {
//You will get your post object here, do what you want now
self.performSegueWithIdentifier("goToDetail", sender: post)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let post = sender as! Posts
let postDetailPage = segue.destinationViewController as? DetailViewController
postDetailPage.passPost = post
}

Answer 2

So, You have not implemented the
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
...
}
and
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
methods in your second implementation.
Also, try putting an invisible button over the collection view cell and assign the tag to be the indexpath of that collectionview cell like this:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
{
....
myButton.tag = indexpath.item
}
After this you may either implement a delegate callback from collectionviewcell class to the homepagetableviewcontroller class or push the detail view controller directly by code.
As far as setting of image in the detail view controller is concerned. You can do it both in viewdidLoad() or viewDidAppear(). Its fine.