deriving from other posts about this topic i tried the following approach - but somehow "foo" as well as "bar" seem to be nil
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewFlowLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
var foo = collectionView.cellForItemAtIndexPath(indexPath) as? messageCell
var bar = foo?.messageText.frame.height
return CGSizeMake(self.view.frame.width-20, bar!+20)
}
the class for the custom cell:
class messageCell: UICollectionViewCell,UIPopoverPresentationControllerDelegate,UITextViewDelegate{
#IBOutlet weak var authorLabel: UILabel!
#IBOutlet weak var timestampLabel: UILabel!
#IBOutlet weak var messageText: UITextView!
func setCell(authorLabelText:String, messageText:String,timestampLabelText:String) {
self.authorLabel?.text = authorLabelText
self.timestampLabel?.text = timestampLabelText
self.messageText?.text = messageText
self.messageText.delegate = self
self.messageText.sizeToFit() //works, i can see different heights when giving a custom color background
println(self.messageText.frame.height)
}
}
Am I supposed to set the height in my custom cell class? That would make no sense as it isnt rendered yet, wouldn't it?
€dit:
A Screenshot from stopping at "foo":
bar is nil because foo is nil - that's what the optional chaining "?" is doing in that expression. If collectionView.cellForItemAtIndexPath(indexPath) as? MessageCell† is nil, it would imply either:
There is no cell at that index path, or
The cell at indexPath is not an instance of MessageCell
I would suggest it's more likely to be the latter, as those delegate messages shouldn't really call with an invalid index path. Where you register your cell class (either in code, or in the storyboard), are you sure you're registering them as MessageCell cells?
† Types should begin with an uppercase character
Related
I'm making a chess app for swift with a chat function. I upload my messages to firebase firestore and then, download them into a [Message] array and display them in a UITableView.
I've been looking around for this on stackoverflow and found that several people are having trouble with sizes of a custom UITableViewCell. I've run into the same problem, but in my case the width of the cell seems to randomly change every time I call .reloadData(). To illustrate :
The first 2 times or so when I type something in my chat it should look like this (the cells in the circle)
But as you can see after a few times this happens :
My code :
Custom cell class
class MessageCustomCell: UITableViewCell {
#IBOutlet weak var dateLabel: UILabel!
#IBOutlet weak var bgView: UIView!
#IBOutlet weak var leftImage: UIImageView!
#IBOutlet weak var messageBubble: UIView!
#IBOutlet weak var messageLabel: UILabel!
#IBOutlet weak var rightImage: UIImageView!
override func awakeFromNib() {
super.awakeFromNib()
messageLabel.numberOfLines = 0
messageBubble.layer.cornerRadius = 5
}
}
TableView delegate methods (TableView = messageView)
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return allMessages.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = messageView.dequeueReusableCell(withIdentifier: "MessageCustomCell") as! MessageCustomCell
//cell.width = tableView.frame.width
let msg = allMessages[indexPath.row]
//cell.frame.size.width = messageView.frame.width
//cell.contentView.frame.size.width = messageView.frame.width
let date = msg.time
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "d/M/yy, h:mm"
let realDate = dateFormatter.string(from: date)
print(msg.fromUserName!)
if msg.fromUserName! == currentUserName {
cell.messageBubble.backgroundColor = UIColor(named: "lightSquare")
cell.messageLabel.textColor = .black
cell.rightImage.isHidden = true
} else {
cell.messageBubble.backgroundColor = UIColor(named: "darkSquare")
cell.messageLabel.textColor = .white
cell.leftImage.isHidden = true
}
cell.dateLabel.text = realDate
cell.messageLabel.text = msg.text!
return cell
}
In my MessageCustomcell.xib file I have a few constraints :
I've put the leftImage, messageBubble (UIView), rightImage in a horizontal stackview. The images have only width and height constraints. The label in the messageBubble has constraints to its superview (top,bottom,trailing,leading)
The stackView has constraints to the bgView (UIView), also top bottom trailing and leading.
Same for the bgView to the safe area.
I've tried setting the frame for the custom cell, but that didn't seem to work, so I've commented that out.
Really hope someone can help me out. If you guys need more info then please do let me know :)
Thanks all.
EDIT :
Here are my constraints for the custom cell xib file.
Alright thanks to #SPatel, who pointed out to make 2 separate .xib files for the receiver chat bubble and the sender chat bubble. This actually worked for my situation and was the right way to go in the first place, instead of manipulating one custom cell for both sender and receiver.
I'm thinking the constraint issue had to do with me trying to hide either the right image or the left image, to change the custom cell appearance for both sides. That must have messed up the whole constraints situation for the custom cell.
Anyway, happy man. Moving on!
I'm facing the following problem, well I have a custom collection view, where I upload an image from the URL I get from a service, everything works fine at the moment but sometimes when scrolling or when I leave the screen and return, my collection view customized it is altered, it does not load correctly, I have seen several posts where they present the same problem in different cases, but trying to conclude that my problem is at the moment of using the SDWebImage library. I have seen that they use methods like the prepareForReuse setting the image to nil but still my problem persists.
So you see the first time
and then it looks like this the second time
Here this my code
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ItemMenuFilterCollectionViewCell", for: indexPath) as! ItemMenuFilterCollectionViewCell
cell.mImgProduct.image = nil
cell.mImgProduct.sd_setImage(with: URL(string: mDataListProducts[indexPath.row].photo!), placeholderImage: UIImage(named: "placeholder.png"))
cell.mTxtProductName.text = mDataListProducts[indexPath.row].shortName
cell.mTxtBrand.text = mDataListProducts[indexPath.row].marca
cell.mTxtStore.text = mDataListProducts[indexPath.row].tienda
cell.mTxtPrice.text = mDataListProducts[indexPath.row].price
cell.mRatingStar.rating = mDataListProducts[indexPath.row].valor?.toDouble() ?? 0
return cell
}
As I mentioned, I think that my problem is in charge of the image with the libreta since I comment on that line of code cell.mImgProduct.sd_setImage(with: URL(string: mDataListProducts[indexPath.row].photo!), placeholderImage: UIImage(named: "placeholder.png"))
All function ok, I would like to know a better way to do it or maybe correct something that is happening to me.
I also have this in the prepareforReuse of my customviewcell but still nothing.
class ItemMenuFilterCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var mRatingStar: CosmosView!
#IBOutlet weak var mImgProduct: UIImageView!
#IBOutlet weak var mTxtProductName: UILabel!
#IBOutlet weak var mTxtBrand: UILabel!
#IBOutlet weak var mTxtStore: UILabel!
#IBOutlet weak var mTxtPrice: UILabel!
override func prepareForReuse() {
self.mImgProduct.sd_cancelCurrentImageLoad()
self.mImgProduct.image = nil
}
}
I currently have a ViewController with a TableView inside it called SelectedListItemsViewController. This ViewController's TableView is populated by a custom cell class called SelectedListItemsTableViewCell.
I have an array of Realm Model Objects called selectedListItems, each of which has several properties. The SelectedListItemsTableViewCell populates the TableView with the listItem property of that indexPath.row's object, and each row has a UIStepper with a UILabel next to it that (as of now) shows UIStepper.value for each row. Ideally, the label will reflect the listItemWeight property of each row, and change it when incrementing or decrementing that row.
This is my custom cell:
class SelectedListItemsTableViewCell: UITableViewCell {
#IBOutlet var selectedListItemLabel: UILabel!
#IBOutlet weak var listItemWeightLabel: UILabel!
#IBOutlet weak var stepperControl: UIStepper!
#IBAction func stepperValueChanged(sender: UIStepper) {
listItemWeightLabel.text = Int(sender.value).description
}
}
And in my ViewController's cellForRowAtIndexPath, I've configured the cell like so:
// Configure the cell...
cell.selectedListItemLabel.text = selectedListItems[indexPath.row].listItem
cell.listItemWeightLabel.text = "\(selectedListItems[indexPath.row].listItemWeight)"
Which perfectly loads the listItem property, and the listItemWeight property shows up correctly, but as soon as I increment or decrement on the UIStepper it gets messed up.
How do I properly link my UILabel and UIStepper to the [indexPath.row].listItemWeight?
In the same method that gets called when your stepper updates, update your listItem. However, since this item is stored in your Realm database, you will have to get an instance of your Realm database and write the change to the database.
You can do this by having your TableViewCell hold on to an instance of the listItem. Your new TableViewCell class will look something like this:
class SelectedListItemsTableViewCell: UITableViewCell {
#IBOutlet var selectedListItemLabel: UILabel!
#IBOutlet weak var listItemWeightLabel: UILabel!
#IBOutlet weak var stepperControl: UIStepper!
var listItem: Item?
#IBAction func stepperValueChanged(sender: UIStepper) {
listItemWeightLabel.text = Int(sender.value).description
if let listItem = listItem {
let realm = try! Realm
try! realm.write {
listItem.listItemWeight = Int(sender.value) ?? 0
}
}
}
}
The above answer was helpful in leading me to the actual solution of my issue, but if anyone in the future is curious - I ended up using a closure.
In my custom cell class, I did
#IBAction func stepperValueChanged(sender: UIStepper) {
selectedListItemLabel.text = Int(sender.value).description
tapped?(self)
}
And in my view controller, I did
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! SelectedListItemsTableViewCell
cell.stepperControl.value = selectedListItems[indexPath.row].listItemWeight
// Configure the cell...
cell.tapped = { (selectedCell) -> Void in
selectedListItems[indexPath.row].listItemWeight = cell.stepperControl.value
}
Which allowed me to access each cell's UIStepper in the view controller file.
It helped to read flashadvanced's Option 2 answer in this thread.
For example here is my custom cell:
protocol SectionHeaderTableViewCellDelegate {
func didSelectUserHeaderTableViewCell(sectionHeader: SectionHeaderTableViewCell, selected: Bool, type: Type)
}
class SectionHeaderTableViewCell: UITableViewCell {
#IBOutlet weak var labelContainerView: LabelContainerView!
#IBOutlet weak var sectionTitleLabel: UILabel!
#IBOutlet weak var plusButton: UIButton!
var type: Type?
var delegate: SectionHeaderTableViewCellDelegate?
var dog: Dog?
let sections = [Type.Meals, Type.Exercise, Type.Health, Type.Training, Type.Misc]
}
extension SectionHeaderTableViewCell {
#IBAction func plusButtonPressed(sender: AnyObject) {
if let type = type {
delegate?.didSelectUserHeaderTableViewCell(self, selected: plusButton.selected, type: type )
}
}
In my controller if I add a return of header.contenView I get the desired results of the header staying in place but unfortunately it nullifies the button included in the custom header preventing it from being called. Otherwise if I simply just return header the button on the custom header cell works as expected but the header moves with the row being deleted which is obviously unsightly and not what I want.
func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
guard let header = tableView.dequeueReusableCellWithIdentifier("sectionHeader") as? SectionHeaderTableViewCell else { return UITableViewCell() }
header.delegate = self
header.updateDogWithGender(dog)
header.type = header.sections[section]
header.sectionTitleLabel.text = header.sections[section].rawValue
return header.contentView
}
moving headers
In case anyone runs into a similar situation the solution was to create a Nib file and customize it as you see fit. Create a nib file by going to File -> New File -> iOS -> User Interface -> and selecting View. Create Nib file. I added my views and buttons to get the look I wanted. customize Nib. From there I changed the custom cell class to be UITableViewHeaderFooterView instead and reconnected my outlets and actions to the new Nib file.
class SectionHeaderView: UITableViewHeaderFooterView {... previous code from above }
Back in the controller update the viewForHeaderInSection function to load a nib instead :
func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let header = NSBundle.mainBundle().loadNibNamed("SectionHeader", owner: self, options: nil).first as? SectionHeaderView
header?.delegate = self
header?.updateDogWithGender(dog)
header?.type = header?.sections[section]
header?.sectionTitleLabel.text = header?.sections[section].rawValue
return header
}
By the way we declared the property first at the end of the loadNibNamed property because it returns an array of AnyObjects and since my Nib file only contains one UIView that houses a label and a button I only needed the first and only item in the array. Thanks to my mentor James for figuring this out!
I have a table view with custom cell that was created as .xib . I didnt use storyboard. I have a problem that I couldnt fill my table with the data which came from webservice result. Also, I have 4 labels in the custom cell. In my custom cell class, when I try to set labels for each items, It gives me fatal error like above.
Here is my code:
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
...
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell!
{
let cell: ItemManagementTVCell = tableView?.dequeueReusableCellWithIdentifier("cell") as ItemManagementTVCell
if let ip = indexPath
{
let item: Item = self.itemList[indexPath.row] as Item
cell.setCell(item.itemName, status: item.itemStatus, duration: item.itemDuration, price: item.itemPrice)
}
return cell
}
}
And my custom cell class is here :
import UIKit
class ItemManagementTVCell: UITableViewCell {
#IBOutlet var lblItemName: UILabel!
#IBOutlet var lblItemPrice: UILabel!
#IBOutlet var lblItemDuration: UILabel!
#IBOutlet var lblItemStatus: UILabel!
override func awakeFromNib()
{
super.awakeFromNib()
}
override func setSelected(selected: Bool, animated: Bool)
{
super.setSelected(selected, animated: animated)
}
func setCell(name: String, status: Int, duration: Int, price: Int)
{
self.lblItemName.text = name
self.lblItemStatus.text = String(status)
self.lblItemDuration.text = "Duration: \(String(duration)) months"
self.lblItemPrice.text = String(price) + " $"
}
}
I am getting the error inside of "setCell" method block.
I have read a lot of questions and solutions and I tried all of them it doesnt work for me.
Thank you for your answers,
Best regards.
SOLUTION: I've solved this problem by linking the cell items to cell's own instead of linking to File's Owner. My problem has gone by doing this.
Another solution to the problem without having to link cell items to the cell owner:
let nib = UINib(nibName: "YOUR_CUSTOM_CELL_NIB_NAME", bundle: nil)
tableView.register(nib, forCellReuseIdentifier: "YOUR_CUSTOM_CELL_ID")
Your "cell" must be nil.
Using
tableView.dequeueReusableCellWithIdentifier("cell") as ItemManagementTVCell
Can return nil. You should use:
tableView.dequeueReusableCellWithIdentifier("cell" forIndexPath:indexPath) as ItemManagementTVCell
This way it guarantees cells is not nil.
EDIT: Maybe you can prevent the crash by putting if statements inside "setCell"
if var itemName = self.lblItemName {
itemName.text = name
}
Do that for every label you set inside it and check if the crash still happens. If it don't you must check why those labels are nil.