func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("nameCell", forIndexPath: indexPath)
let pancakeHouse = pancakeHouses[indexPath.row]
if let cell = cell as? FAQsViewCell {
cell.pancakeHouse = pancakeHouse
} else {
cell.textLabel?.text = pancakeHouse.que
}
return cell
}
I got error in this function of UITableViewController when I run my project at that time I got it I can't understand why it came or what is its meaning.
The "definition conflicts with previous value" occurred also when you forgot to set the Cell Identifier
Make sure you have set the correct identifier to your custom cell (in your case "nameCell") :
Related
I am getting following errors:
1) Non-optional expression of type 'UITableViewCell' used in a check for optionals
2) Value of type 'UITableViewCell' has no member 'congigureCell'
Please
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell:UITableViewCell = countryList.dequeueReusableCell(withIdentifier: "cell")! as UITableViewCell // Error 1 happens here {
let text: String!
if inSearchMode {
text = filteredCountriesList[indexPath.row]
} else {
text = countriesList[indexPath.row]
}
cell.congigureCell(text: text) // Error 2 happens here
return cell
} else {
return UITableViewCell()
}
}
1) The ! mark at the end of
countryList.dequeueReusableCell(withIdentifier: "cell")!
uses force unwrap to make it non-optional, so you shouldn't check it inside if let, or even better way is to just remove ! mark
2) congigureCell probably the method of different class, not UITableViewCell. You should substitude UITableViewCell by this class to cast it
Make sure you have done following steps.
Add cell identifier in storyboard to your custom cell. i.e "cell"
Assign delegate and datasource of your YourTableview to YOURViewController.swift via storyboard or in code.
In YOURViewController.swift access cell using datasource of table
view as.
Add a custom class of sub class UITableViewCell and assign it to
tour cell in storyboard.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = countryList.dequeueReusableCell(withIdentifier: "cell") as! YOURTableViewCellClass {
let text: String!
if inSearchMode {
text = filteredCountriesList[indexPath.row]
} else {
text = countriesList[indexPath.row]
}
cell.congigureCell(text: text) // Error 2 happens here
return cell }
The ! mark is uses to force unwrap the optional value that can be nil. But "if let" and "guard let" has been check for optionals, so you don't need ! mark.
Just use
if let cell:UITableViewCell = countryList.dequeueReusableCell(withIdentifier: "cell") as UITableViewCell
cell in this line is 'UITableViewCell', but congigureCell is not a member of UITableViewCell.
If you want to use your own cell(like MyCell), you should convert it to MyCell.
let myCell = cell as! MyCell
1 .Instead of dequeueReusableCellWithIdentifier: use dequeueReusableCellWithIdentifier:forIndexPath: the later one never provides a nil value so you dont need to worry about the 'nil error'.
2.UItableViewCell dont have configure cell or congigureCell as in your case instead you have to create a custom tableViewCell and add function as configureCell() and then in this line
if let cell:UITableViewCell = countryList.dequeueReusableCell(withIdentifier: "cell")! as UITableViewCell
replace as UITableViewCell as as yourCustomTableViewCellClass
I'm new to coding so I not sure how to fix this error:
private let cellReuseIdentifier = "ArticleViewCell"
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier(cellReuseIdentifier) as? UITableViewCell
if cell == nil {
cell = ArticleViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: cellReuseIdentifier)
}
I get this error:
Downcast from 'UITableViewCell?' to 'UITableView only warps optionals; did you mean to use "!"?
I tried changing the ? to ! put it get an error also.
Try
let cell = tableView.dequeueReusableCellWithIdentifier("Cell",forIndexPath: indexPath) as! UITableViewCell
Also do not forget to return the cell.
return cell
You do not need to unwrap it at all:
var cell = tableView.dequeueReusableCellWithIdentifier(cellReuseIdentifier)
Try:
let cell = tableView.dequeueReusableCellWithIdentifier(cellReuseIdentifier) as! <ClassName>
Where "ClassName" is the name of the class for the article tableview cell.
after you create cell, when you use it you should add a "!" after the cell such as:
return cell!
I have a UITableView in my ViewController.
One of the cell could be tap into another TableViewController to allow select a value.
I want to update my cell after back from the callee ViewController.
right now, i could pass back the selected value by delegate.
However, i tried following way, none of them works.
self.mainTable.reloadData()
dispatch_async(dispatch_get_main_queue()) {
self.mainTable.reloadData()
}
self.mainTable.beginUpdates()
self.mainTable.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.None)
self.mainTable.endUpdates()
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
was called and executed without error.
but the UI just doesn't change
here is the way I update value in cellForRowAtIndexPath
if let currentCell = tableView.cellForRowAtIndexPath(indexPath) as UITableViewCell! {
currentCell.textLabel?.text = address
return currentCell
}
Here is my cellForRowAtIndexPath -
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let id = "Cell"
println(indexPath)
if indexPath.row == 1 {
var cell = tableView.dequeueReusableCellWithIdentifier(id) as? UITableViewCell
if cell == nil {
cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: id)
cell?.contentMode = UIViewContentMode.Center
cell?.selectionStyle = UITableViewCellSelectionStyle.None
cell?.contentView.addSubview(mapView!)
}
return cell!
}else{
let cell = UITableViewCell()
cell.textLabel?.text = self.address
return cell
}
}
Here is the delegate method -
func passBackSelectedAddress(address: String) {
self.address = address
var indexPath = NSIndexPath(forRow: 0, inSection: 0)
self.mainTable.beginUpdates()
self.mainTable.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Automatic)
self.mainTable.endUpdates()
}
My fix:
After more debug, i find the cause,
the self.address value is updated in delegate, however it roll back to previous value in cellForRowAtIndexPath.
I change the property to a static property, then resolve the problem.
I'm not sure what's wrong with instance property, and why it reverses back.
static var _address:String = ""
It seems like you're trying to grab a cell from the UITableView and then update the textLabel value that way. However, UITableView and UITableViewCell are not meant to be updated in this way. Instead, store the value of address in your class and update this value when the delegate calls back into your class. If cellForRowAtIndexPath constructs the UITableViewCell with the value of self.address, calling mainTable.reloadData() after should update the cell to the new value.
For example:
var address: String
func delegateCompleted(address: String) {
self.address = address
self.mainTable.reloadData()
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(<your identifier>)
if (indexPath == <your address cell indexPath>) {
let textLabel = <get your textLabel from the cell>
textLabel?.text = self.address
}
return cell
}
Your cellForRowAtIndexPath has some problems -
You are using the same re-use identifier for different types of cell (one with a map, one without)
When you allocate the table view cell for the other row, you don't include the re-use identifier.
You have no way of referring to the map view that you are adding after the method exits because you don't keep a reference.
If you are using a storyboard then you should create the appropriate prototype cells and subclass(es) and assign the relevant cell reuse ids. If you aren't then I suggest you create a cell subclass and register the classes against the reuse identifiers. Your cellForRowAtIndexPath will then look something like -
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var returnCell:UITableViewCell
if indexPath.row == 1 {
var myMapCell = tableView.dequeueReusableCellWithIdentifier("mapCell", forIndexPath:indexPath) as MYMapCell
myMapCell.contentMode = UIViewContentMode.Center
myMapCell.selectionStyle = UITableViewCellSelectionStyle.None
// Set the properties for a map view in the cell rather than assigning adding an existing map view
returnCell=myMapCell
}else{
returnCell = tableView.dequeueReusableCellWithIdentifier("addressCell", forIndexPath:indexPath)
returnCell.textLabel?.text = self.address
}
return returnCell;
}
I get this error when the ViewController loads.
I don't know, what I can do
The loadDataFromDb function is this
func loadDataFromDb() {
let fetchRequest = NSFetchRequest(entityName: "Chats")
daten = self.context!.executeFetchRequest(fetchRequest, error: nil) as! [Model]
tableView.reloadData()
}
I googled that error but nothing helped me
dequeueReusableCellWithIdentifier returns an optional that might be nil.
Your force casting to UITableViewCell, by using as! makes it so that the nil gets casted to UITableViewCell and you end up calling a method on nil, which leads to the exception.
Try unwrapping the cell, by using if let before using it or better yet use dequeueReusableCellWithIdentifier(_ identifier: String,
forIndexPath indexPath: NSIndexPath) -> AnyObject , which doesn't return an optional.
Also as a whole, try staying away from ! and refrain from using it, unless you absolutely have to.
Edit:
Here's one way to do it
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as? UITableViewCell {
cell.textLabel?.text = "Text"
return cell
}
return UITableViewCell()
}
I'm trying to switch between two custom cell-classes in swift, but I can't seem to figure out how to return the cell.
My code looks like this, and the error is in the last line:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
if istrue{
var cell: CustomTableCell = self.tv.dequeueReusableCellWithIdentifier("cell") as CustomTableCell
let data = myList[indexPath.row] as Model
cell.customLabel.text = data.username
cell.dateLabel.text = printDate(data.date)
return cell
}else{
var cell: CustomTableCell2 = self.tv.dequeueReusableCellWithIdentifier("cell") as CustomTableCell2
let data = myList[indexPath.row] as Model
cell.titleLabel.text = data.username
cell.dateLabel2.text = printDate(data.date)
return cell
}
}return nil
I've also tried to "return cell" in the last line and to delete the other two lines of "return cell" in the if- and else-statements but that didn't work, it just gives me the error saying "cell" is an unresolved identifier.
I've never done this before so I'm not sure if this is the right way of tackling the problem either.
Any suggestions on how to proceed would be appreciated.
Define a variable of UITableViewCell type and initialize it in both the if and the else branches, then use it as the return value:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
var retCell: UITableViewCell
if istrue{
var cell: CustomTableCell = self.tv.dequeueReusableCellWithIdentifier("cell") as CustomTableCell
let data = myList[indexPath.row] as Model
cell.customLabel.text = data.username
cell.dateLabel.text = printDate(data.date)
retCell = cell
}else{
var cell: CustomTableCell2 = self.tv.dequeueReusableCellWithIdentifier("cell") as CustomTableCell2
let data = myList[indexPath.row] as Model
cell.titleLabel.text = data.username
cell.dateLabel2.text = printDate(data.date)
retCell = cell
}
return retCell
}
Note that you cannot return nil because the return type of this method is a non-optional UITableViewCell, so it must always be an instance of (a class derived from) UITableViewCell.
Alternatively, you can just return the cell as you do on each of the if and else branches, but remove the ending return out of the if/else scope - it's not needed. Moreover, in your code it is also misplaced because out of the method scope.
Personal note: in functions I usually avoid return statements in the middle of the body, preferring a single exit path at the end - that's just a personal preference, so feel free to choose the one that you like more.