I have been unable to use the didHighlightItem and didUnhighlightItem functions to correctly animate when a cell is clicked, as I am unable to access the cell's section number. I was wondering whether I am solving the problem incorrectly, or whether there is a way of accessing the SectionController's section index in the collection view. My code is as follows:
class PersonSectionController: ListSectionController {
var current: Person?
override init() {}
override func didUpdate(to object: Any) {
if let person = object as? Person {
current = person
}
}
// Number of items displayed per object
override func numberOfItems() -> Int {
return 1
}
// Dequeue and configure cell
override func cellForItem(at index: Int) -> UICollectionViewCell {}
// Returns the required cell size at the given index
override func sizeForItem(at index: Int) -> CGSize {}
override func didHighlightItem(at index: Int) {
if let viewController = self.viewController as? PeopleViewController {
if let cell = viewController.peopleCollectionView.cellForItem(at: IndexPath(row: index, section: 0)) {
UIView.animate(withDuration: 0.1) {
cell.transform = CGAffineTransform(scaleX: 0.95, y: 0.95)
}
}
}
}
override func didUnhighlightItem(at index: Int) {
if let viewController = self.viewController as? PeopleViewController {
if let cell = viewController.peopleCollectionView.cellForItem(at: IndexPath(row: 0, section: index)) {
UIView.animate(withDuration: 0.1) {
cell.transform = CGAffineTransform.identity
}
}
}
}
}
Thanks in advance!
I think that you need to access the cell from the collectionContext:
override func didHighlightItem(at index: Int) {
guard let cell = collectionContext?.cellForItem(at: index) else { return }
// Animation stuff
}
Related
I'm trying to add a new NSTextView to the last index in my collection view every time the attributed string exceeds a certain bounds. The code works perfectly until the 5th item then it starts its starts creating an item every time the enter button is pressed. I'm thinking its a bug but im not sure. if any one can show me a better way to do it or improve the current code I have I would appreciate it. Below is my code:
Here is the CollectionViewItem
class DocumentItem: NSCollectionViewItem {
var itemView: DocumentTextView?
override func viewDidLoad() {
super.viewDidLoad()
self.itemView?.wantsLayer = true
// Do view setup here.
}
override func loadView() {
self.itemView = DocumentTextView(frame: NSZeroRect)
self.view = self.itemView!
}
func getView() -> DocumentTextView {
return self.itemView!
}
}
Here is the collectionView datasource
func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
return DocList.count
}
func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
let item = collectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "DocumentItem"), for: indexPath)
return item
}
Here is the NSTextView subclass
class DocumentTextView: NSTextView {
var theContainer = NSTextContainer()
var theStorage = NSTextStorage()
var theManager = NSLayoutManager()
var table = NSTextTable()
var pdfPage: PDFPage?
override init(frame frameRect: NSRect) {
super.init(frame: NSRect(origin: frameRect.origin, size: NSSize(width: 800, height: 1131 )), textContainer: theContainer)
theStorage.addLayoutManager(theManager)
theManager.addTextContainer(theContainer)
self.textContainerInset = CGSize(width: 50, height: 50)
self.textContainer?.widthTracksTextView = true
self.textContainer?.heightTracksTextView = true
self.textContainer?.lineBreakMode = .byWordWrapping
self.maxSize = NSSize(width: 800, height: 1131)
self.backgroundColor = NSColor.fromHexString("ffffff")!
self.isRichText = true
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Here is the function bringing the bug
func textDidChange(_ notification: Notification) {
var textView = notification.object as? DocumentTextView
let numberOfItems = theDocumentOutlineView.numberOfItems(inSection: 0)
let theLastTextView = theDocumentOutlineView.item(at: numberOfItems - 1) as! DocumentItem
if textView == theLastTextView.itemView {
print(textView?.attributedString().size())
if (textView?.attributedString().size().height)! >= 1106.0 {
self.DocList.append(2)
var set = Set<IndexPath>()
set.insert(NSIndexPath(forItem: self.DocList.count - 1 , inSection: 0) as IndexPath)
theDocumentOutlineView.insertItems(at: set)
theDocumentOutlineView.scrollToItems(at: set, scrollPosition: NSCollectionView.ScrollPosition.top)
var newFirstResponder = theDocumentOutlineView.item(at: self.DocList.count - 1) as! DocumentItem
newFirstResponder.itemView?.delegate = self
self.view.window?.makeFirstResponder(newFirstResponder.itemView)
}
}
}
Here's my test project, maybe it helps. The delegate of the text view is its view controller, the NSCollectionViewItem. The view controller of the collection view also receives NSText.didChangeNotification notifications to check the length of the text. heightTracksTextView of the text container is false.
ViewController:
class ViewController: NSViewController, NSCollectionViewDataSource, NSCollectionViewDelegate {
#IBOutlet weak var collectionView: NSCollectionView!
var docList: [DocumentObject] = [DocumentObject(index: 0, string: NSAttributedString(string: "New 0"))]
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(DocumentItem.self, forItemWithIdentifier: NSUserInterfaceItemIdentifier("DocumentItem"))
NotificationCenter.default.addObserver(self, selector: #selector(textDidChange),
name: NSText.didChangeNotification, object: nil)
}
func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
return docList.count
}
func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {
if let item = collectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier("DocumentItem"),
for: indexPath) as? DocumentItem {
item.representedObject = docList[indexPath.item]
return item
}
return NSCollectionViewItem()
}
#objc func textDidChange(_ notification: Notification) {
if let textView = notification.object as? NSTextView {
if let theLastItem = self.collectionView.item(at: self.docList.count - 1) as? DocumentItem,
textView === theLastItem.itemView {
//if textView.attributedString().size().height >= 1106.0 {
print("\(textView.attributedString().size().height) \(textView.layoutManager!.usedRect(for: textView.textContainer!).size.height)")
if let textContainer = textView.textContainer,
let heigth = textView.layoutManager?.usedRect(for: textContainer).size.height,
heigth >= 1106.0 {
DispatchQueue.main.async {
if let window = self.view.window,
window.makeFirstResponder(nil) { // end editing of previous item
self.docList.append(DocumentObject(index: self.docList.count - 1, string: NSAttributedString(string: "New \(self.docList.count)")))
let set: Set = [IndexPath(item: self.docList.count - 1, section: 0)]
self.collectionView.insertItems(at: set)
self.collectionView.scrollToItems(at: set, scrollPosition: NSCollectionView.ScrollPosition.top)
if let newItem = self.collectionView.item(at: self.docList.count - 1) as? DocumentItem {
window.makeFirstResponder(newItem.itemView)
}
}
}
}
}
}
}
}
DocumentItem:
class DocumentItem: NSCollectionViewItem, NSTextViewDelegate {
var itemView: DocumentTextView?
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
}
override func loadView() {
self.itemView = DocumentTextView(frame: NSZeroRect)
self.view = self.itemView!
self.itemView?.delegate = self
}
override var representedObject: Any? {
didSet {
if let item = representedObject as? DocumentObject {
itemView?.textStorage?.setAttributedString(item.string)
}
}
}
func textDidEndEditing(_ notification: Notification) {
if let item = representedObject as? DocumentObject {
item.string = itemView?.textStorage?.copy() as! NSAttributedString
}
}
}
DocumentObject:
class DocumentObject {
var index: Int
var string: NSAttributedString
init(index: Int, string: NSAttributedString) {
self.index = index
self.string = string
}
}
Trying to implement the IGListKit library, I'm running into the issue that my cells are updated unnecessarily. I'm using a singleton adapter.dataSource with one section per row in the table.
Minimum example:
import IGListKit
class ContentItem: ListDiffable {
weak var item: Content?
weak var section: ContentSectionController?
func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
return true
}
init(item: Content?) {
self.item = item
}
}
class ContentSectionController: ListSectionController {
weak var object: ContentItem?
override func didUpdate(to object: Any) {
self.object = object as? ContentItem
self.object?.section = self
// should only be called on updates
}
override func sizeForItem(at index: Int) -> CGSize {
guard let content = object?.item else {
return CGSize(width: 0, height: 0)
}
// calculate height
}
override func cellForItem(at index: Int) -> UICollectionViewCell {
let cell = collectionContext!.dequeueReusableCellFromStoryboard(withIdentifier: "ContentCell", for: self, at: index)
(cell as? ContentCell)?.item = object // didSet will update cell
return cell
}
override init() {
super.init()
self.workingRangeDelegate = self
}
}
extension ContentSectionController: ListWorkingRangeDelegate {
func listAdapter(_ listAdapter: ListAdapter, sectionControllerWillEnterWorkingRange sectionController: ListSectionController) {
// prepare
}
func listAdapter(_ listAdapter: ListAdapter, sectionControllerDidExitWorkingRange sectionController: ListSectionController) {
return
}
}
class ContentDataSource: NSObject {
static let sharedInstance = ContentDataSource()
var items: [ContentItem] {
return Content.displayItems.map { ContentItem(item: $0) }
}
}
extension ContentDataSource: ListAdapterDataSource {
func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
return items
}
func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
return ContentSectionController()
}
func emptyView(for listAdapter: ListAdapter) -> UIView? {
return nil
}
}
/// VC ///
class ContentViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
let updater = ListAdapterUpdater()
adapter = ListAdapter(updater: updater, viewController: self, workingRangeSize: 2)
adapter.collectionView = collectionView
adapter.dataSource = ContentDataSource.sharedInstance
}
var adapter: ListAdapter!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
adapter.performUpdates(animated: true)
}
// ...
}
On every view appear I call adapter.performUpdates(animated: true), which should never update the cells since isEqual is overridden with true. Nonetheless, all cells' didUpdate is triggered, calling cellForItem again too.
IGListKit requires both diffIdentifier and isEqual to be implemented with the IGListDiffable protocol in order to compare the identity/equality of two objects. (You're missing the diff identifier in your model).
My understanding is that under the hood, ListKit checks to see if the two diff identifiers of the objects are equal, if they are THEN it moves on to comparing them with isEqual.
Resources:
IGListKit Best Practices
IGListDiffable Protocol Reference
I have a UI widget as follows
class ProfileBubbleCell: UITableViewCell {
var roundImageView: UIImageView?
override func awakeFromNib() {
super.awakeFromNib()
self.contentView.backgroundColor = Color.red
initImage()
}
private func initImage(){
let imageView = UIImageView()
let width = self.frame.width
let height = self.frame.height
let img_width = height - 4
let img_height = img_width
let y = 2
let x = width/2 - img_width/2
imageView.frame = CGRect(
x: x, y: CGFloat(y), width: img_width, height: img_height
)
let rounded = imageView
.makeRounded()
.border(width:2.0, color:Color.white.cgColor)
// attach and save reference
self.addSubview(rounded)
self.roundImageView = rounded
}
private func loadImage(){
// #TODO: call parent function
}
}
And in loadImage, I would like to call the parent's image loading view, and when the image is loaded, display it in roundImageView. ProfileBubbleCell is really meant to be as generic as possible, its only concern is making the image round and centering it.
This looks like a very common use case and I would like to delegate the loading image task to the parent, but I am not sure how to express it.
In the parent I instantiate the cell as follows:
let cell = tableView.dequeueReusableCell(withIdentifier: "ProfileBubbleCell", for: indexPath) as! ProfileBubbleCell
Here show you some about delegate use.
// 1) define delegate.
protocol ProfileBubbleCellDelegate {
func getImage() -> UIImage?
}
class ProfileBubbleCell: UITableViewCell {
// 2) declare a variable of ProfileBubbleCellDelegate
weak var delegate: ProfileBubbleCellDelegate?
//
func configure() {
self.roundImageView.image = delegate.getImage()
}
}
// when dequeueReuseCell on cellForRow(at:)
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "ProfileBubbleCell", for: indexPath) as ProfileBubbleCell else { return UITableView() }
// 3) assign delegate to tableView's superView, maybe it's a UIViewController or UIView on your class.
cell.delegate = self
cell.configure()
return cell
}
// 4) extension Your class who be assigned delegate of ProfileBubbleCellDelegate
// and implement delegate's method.
extension YourClass: ProfileBubbleCellDelegate {
func getImage() -> UIImage? {
// 5) provide image.
return hereProvideYourImage
}
}
// or if you want immediately download image when cell.roundedImageView need it.
// modify the getImage() of Delegate like this.
protocol ProfileBubbleCellDelegate {
func getImage(completion: #escaping ((UIImage?) -> Void))
}
// then the extension implement will be
extension YourClass: ProfileBubbleCellDelegate {
func getImage(completion: #escaping ((UIImage?) -> Void)) {
downloadImageTask.downloadImage(url: imageUrl, completion: { downloadedImage in
// because completion will be passed on other closure of downloadImage(completion:),
// so delegate method need add `#escaping` that means the completion can escape from itself closure.
completion?(downloadedImage)
})
}
}
// don't forget replace called method on cell.
class ProfileBubbleCell: UITableViewCell {
// ...
func configure() {
delegate.getImage(completion: { downloadedImage in
DispatchQueue.main.async {
self.roundImageView.image = downloadedImage
}
})
}
}
When I load the first time my UICollectionView does not have any problem, Im using custom layouts and a serachbar, when I search some text it crashes throwing the exception that the cell with an index path that does not exist, Im using the search bar like the next code:
import UIKit
import AVFoundation
class CategoryViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UISearchBarDelegate {
var ListArray : JSON! = []
var SelectedIds: [Int] = []
var SearchActive : Bool = false
var SearchArray = [Int]()
#IBOutlet weak var SearchCategories: UISearchBar!
#IBOutlet weak var CategoryCollection: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
if let layout = self.CategoryCollection.collectionViewLayout as? InterestsLayout {
layout.delegate = self
}
self.CategoryCollection.backgroundColor = UIColor.clearColor()
self.CategoryCollection.contentInset = UIEdgeInsets(top: 18, left: 3, bottom: 10, right: 3)
// Search Delegate
self.SearchCategories.delegate = self
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
self.LoadData()
}
func LoadData() {
MUBService.categoriesList(self) { (categories_list) -> () in
self.ListArray = categories_list
self.CategoryCollection.reloadData()
self.view.hideLoading()
}
}
func dismissKeyboard() {
view.endEditing(true)
self.SearchCategories.showsCancelButton = false
}
func searchBarTextDidBeginEditing(searchBar: UISearchBar) {
self.SearchCategories.showsCancelButton = true
self.SearchActive = true
}
func searchBarTextDidEndEditing(searchBar: UISearchBar) {
self.SearchActive = false
}
func searchBarCancelButtonClicked(searchBar: UISearchBar) {
self.SearchActive = false
self.dismissKeyboard()
}
func searchBarSearchButtonClicked(searchBar: UISearchBar) {
self.SearchActive = false
}
func searchBar(searchBar: UISearchBar, let textDidChange searchText: String) {
self.SearchArray = []
for (index, object) in self.ListArray["categories"] {
let name = object["name"].string!
if name.localizedStandardContainsString(searchText) == true {
self.SearchArray.append(Int(index)!)
}
}
if(self.SearchArray.count == 0){
self.SearchActive = false;
} else {
self.SearchActive = true;
}
self.CategoryCollection.reloadData()
}
}
extension CategoryViewController {
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
self.CategoryCollection?.collectionViewLayout.invalidateLayout()
return 1
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if(self.SearchActive && self.SearchArray.count > 0) {
return self.SearchArray.count
}
return self.ListArray["categories"].count
}
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CategoryCell", forIndexPath: indexPath) as! CategoryCell
let row = indexPath.row
if(self.SearchActive && self.SearchArray.count > 0) {
let category = self.ListArray["categories"][self.SearchArray[row]]
cell.configureWithPhoto(category, selected: self.ListArray["selected"])
}else{
let category = self.ListArray["categories"][row]
cell.configureWithPhoto(category, selected: self.ListArray["selected"])
}
return cell
}
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
let cell = self.CategoryCollection.cellForItemAtIndexPath(indexPath) as! CategoryCell
cell.changeBackGroundColor()
if (cell.is_active == true){
self.SelectedIds.append(cell.id)
}else{
self.SelectedIds.removeObject(cell.id)
}
}
#IBAction func RegisterDidTouch(sender: AnyObject) {
MUBService.setMyCategories(self.SelectedIds, view_controller: self) { (categories_selected) -> () in
self.performSegueWithIdentifier("HomeTabBarFromCategoriesSegue", sender: self)
}
}
}
extension CategoryViewController : InterestsLayoutDelegate {
// 1. Returns the photo height
func collectionView(collectionView:UICollectionView, heightForPhotoAtIndexPath indexPath:NSIndexPath , withWidth width:CGFloat) -> CGFloat {
var row = indexPath.row
if(self.SearchActive && self.SearchArray.count > 0) {
row = self.SearchArray[row]
}
let category = self.ListArray["categories"][row]
let url = NSURL(string:category["image"].string!)
let data = NSData(contentsOfURL:url!)
let image = UIImage(data:data!)!
let boundingRect = CGRect(x: 0, y: 0, width: width, height: CGFloat(MAXFLOAT))
let rect = AVMakeRectWithAspectRatioInsideRect((image.size), boundingRect)
return rect.size.height
}
// 2. Returns the annotation size based on the text
func collectionView(collectionView: UICollectionView, heightForAnnotationAtIndexPath indexPath: NSIndexPath, withWidth width: CGFloat) -> CGFloat {
let annotationPadding = CGFloat(4)
let annotationHeaderHeight = CGFloat(17)
var row = indexPath.row
if(self.SearchActive && self.SearchArray.count > 0) {
row = self.SearchArray[row]
}
let category = self.ListArray["categories"][row]
let font = UIFont(name: "AvenirNext-Regular", size: 10)!
let rect = NSString(string: category["name"].string!).boundingRectWithSize(CGSize(width: width, height: CGFloat(MAXFLOAT)), options: .UsesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
let commentHeight = ceil(rect.height)
var height = annotationPadding + annotationHeaderHeight + commentHeight + annotationPadding
if (height != 70){
height = 70
}
return 70
}
}
I don't understand what is happening, thanks a lot for your help
I've faced the same problem. Here an explanation: if you use a custom collectionViewLayout and you have a cache for layout attributes (best practice so you don't have to calculate every time attributes), you have to override invalidateLayout method in your custom layout class and purge your cache.
Here's my layout attributes array
private var cache = [UICollectionViewLayoutAttributes]()
Here the overrided method
override func invalidateLayout() {
super.invalidateLayout()
cache.removeAll()
}
I call layout invalidation in my textDidChange delegate
func searchBar(searchBar: UISearchBar, textDidChange searchText: String) {
if searchText.characters.count > 0 {
// search and reload data source
self.searchBarActive = true
self.filterContentForSearchText(searchText)
self.collectionView?.collectionViewLayout.invalidateLayout()
self.collectionView?.reloadData()
}else{
self.searchBarActive = false
self.collectionView?.collectionViewLayout.invalidateLayout()
self.collectionView?.reloadData()
}
}
import UIKit
class FeedTableViewController: UITableViewController {
var navBar:UINavigationBar=UINavigationBar()
let font = UIFont(name: "Baskerville", size: 15)
var feedData:NSMutableArray = NSMutableArray()
required init(coder aDecoder: NSCoder){
super.init(coder: aDecoder)
}
#IBAction func likeButton(sender: AnyObject) {
if var votes:Int? = quote!.objectForKey("votes") as? Int {
votes!++
}
}
#IBAction func loadData(sender: AnyObject?) {
feedData.removeAllObjects()
var findFeedData:PFQuery = PFQuery(className: "userQuotes")
findFeedData.findObjectsInBackgroundWithBlock{
(objects:[AnyObject]?, error:NSError?)->Void in
if error == nil{
if let objs = objects{
for object in objs{
let quote:PFObject = object as! PFObject
self.feedData.addObject(quote)
// let user:PFUser = (object as! NSArray).lastObject as! PFUser
}
//println(self.feedData)
let array:NSArray = self.feedData.reverseObjectEnumerator().allObjects
self.feedData = NSMutableArray(array: array)
NSOperationQueue.mainQueue().addOperationWithBlock({
self.tableView.reloadData()
})
}
}
}
}
override func viewDidAppear(animated: Bool) {
self.loadData( nil )
}
override func viewDidLoad() {
super.viewDidLoad()
self.title = "Quotezilla"
// 3
//self.navigationItem.setRightBarButtonItem(rightSearchBarButtonItem, animated: true)
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Potentially incomplete method implementation.
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete method implementation.
// Return the number of rows in the section.
return feedData.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell:QuoteTableViewCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! QuoteTableViewCell
let quote:PFObject = self.feedData.objectAtIndex(indexPath.row) as! PFObject
cell.contentTextView!.font = font
cell.timeStampLabel!.font = font
cell.publisherLabel!.font = font
cell.contentTextView.alpha = 0
cell.timeStampLabel.alpha = 0
cell.publisherLabel.alpha = 0
cell.contentTextView.text = quote.objectForKey("content") as! String
//cell.publisherLabel.text = quote.objectForKey("publisher") as? String
/* func loadLikes(){
if var votes:Int? = quote.objectForKey("votes") as? Int {
votes!++
}
}*/
var dateFormatter:NSDateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "EEEE, MMM d, h:mm a"
cell.timeStampLabel.text = dateFormatter.stringFromDate(quote.createdAt!)
var votes:Int? = quote["votes"] as? Int
if votes == nil {
votes = 0
}
cell.likesLabel?.text = "\(votes!)"
var myObject = quote["publisher"] as? PFObject
myObject?.fetchIfNeeded()
if let foundUser = myObject as? PFUser{
cell.publisherLabel.text = foundUser.username
UIView.animateWithDuration(0.7, animations: {
cell.contentTextView.alpha = 1
cell.timeStampLabel.alpha = 1
cell.publisherLabel.alpha = 1
})
}
return cell
}
So what I am essentially attempting to do is create a likes or votes button. As you see in the code I have a likeButton action that is supposed to auto-increment the likes section in parse. I display the current likes that I have filled into the rows in Parse itself in the cellForRowAtIndexPath function. The problem is that I cannot call quote.objectForKey("votes"), because I initialize it later. I have been poring over this problem and cannot find a way to make the votes update in parse through the likeButton action.
You must live with life on the network. That means your table won't have certain data available when the App starts. Handle a missing object or missing key within a particular cell gracefully and just use some kind of placeholder value. When the parse callback executes, you are already correctly forcing a refresh.
OK So BIG EDIT
This class needed a lot of work. I'm not even going to spell out every change here, but it's basically a complete Parse.com tutorial at this point.
This code compiles cleanly but I can't be sure of everything in your context. In particular do you have a 'likesButton' on every table row as part of your custom table cell view? I'm assuming that.
class FeedTableViewController: UITableViewController {
var navBar = UINavigationBar()
let font = UIFont(name: "Baskerville", size: 15)
var feedData = [PFObject]()
static let cellID = "cell"
// NOTE! See how this tag is set below
#IBAction func likeButton(sender: UIButton) {
let quote = feedData[sender.tag]
if let votes = quote.objectForKey("votes") as? Int {
quote.setObject(votes + 1, forKey: "votes")
}
else {
// CHALLENGE FOR YOU: handle the case of no votes attribute
}
// UPDATE the local UI
tableView.reloadRowsAtIndexPaths([NSIndexPath(forRow: sender.tag, inSection: 0)],
withRowAnimation: .None)
// CHALLENGE FOR YOU: UPDATE Parse...start a new question if necessary
}
#IBAction func loadData(sender: AnyObject?) {
feedData.removeAll()
PFQuery(className: "userQuotes").findObjectsInBackgroundWithBlock {
[unowned self]
(objects: [AnyObject]?, error: NSError?) -> Void in
if let objs = objects {
for object in objs {
self.feedData.append(object as! PFObject)
}
self.feedData = self.feedData.reverse()
}
NSOperationQueue.mainQueue().addOperationWithBlock { self.tableView.reloadData() }
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.loadData(nil)
self.title = "Quotezilla"
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return feedData.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(FeedTableViewController.cellID, forIndexPath: indexPath) as! QuoteTableViewCell
cell.likesButton!.tag = indexPath.row // See how tag works with the above
cell.contentTextView!.font = font
cell.timeStampLabel!.font = font
cell.publisherLabel!.font = font
cell.contentTextView.alpha = 0.0
cell.timeStampLabel.alpha = 0.0
cell.publisherLabel.alpha = 0.0
let q = feedData[indexPath.row]
if let content = q.objectForKey("content") as? String {
cell.contentTextView.text = content
}
else {
cell.contentTextView.text = "Content not found!"
}
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "EEEE, MMM d, h:mm a"
cell.timeStampLabel.text = dateFormatter.stringFromDate(q.createdAt!)
let votes = (q.objectForKey("votes") as? Int) ?? 0
cell.likesLabel?.text = "\(votes)"
let myObject = q.objectForKey("publisher") as? PFObject
myObject?.fetchInBackgroundWithBlock {
[unowned self]
(object: PFObject?, error: NSError?) in
NSOperationQueue.mainQueue().addOperationWithBlock {
if let foundUser = object as? PFUser {
cell.publisherLabel.text = foundUser.username
UIView.animateWithDuration(0.7) {
cell.contentTextView.alpha = 1.0
cell.timeStampLabel.alpha = 1.0
cell.publisherLabel.alpha = 1.0
}
}
else {
cell.publisherLabel.text = "Publisher not found!"
}
}
}
return cell
}
}