I want to access my view objects from UITableViewCell, but I cannot. I can't cast my cell object because I only have the string UITableViewCell. For example "ClientTableViewCell".
How can I access the views and objects in the cell without casting?
I tried to do as follows:
let cell = (val as AnyObject).dequeueReusableCell(withIdentifier: "ClientTableViewCell") as! UITableViewCell
I can get a cell like this but I can't reach the contents.Itried mirror reflection like this:
let mirror = Mirror(reflecting: cell)
but child label and value comes some optional
guard let cell: ClientTableViewCell = tableView.dequeueReusableCell(withIdentifier: String(describing: ClientTableViewCell.self), for: indexPath) as? ClientTableViewCell else { return UITableViewCell() }
try this
I never get this print . it is like is always nil, doesnt matter how much i scroll it up or down :/
if let update = tableView.cellForRow(at: indexPath ) as? RestCell {
print("VISIBLE CELL")
}
Complete code..
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell : RestCell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! RestCell
// Pass data to Cell :) clean the mess at the View Controller ;)
cell.restData = items[indexPath.row]
// Send cell so it can check update the image to the right cell ;)
// cell.cell = tableView.cellForRow(at: indexPath ) as? RestCell
//print("LA CELDA ES \(tableView.cellForRow(at: indexPath ))")
if let update = tableView.cellForRow(at: indexPath ) as? RestCell {
print("VISIBLE CELL")
}
return cell
}
You have not returned your cell from cellForRow method so this is the reason why your if statement is returning false. I'm not sure why you are trying to do this but there have to be a better way. If you want to look for visible cells you can use UITableView visibleCells variable.
I have currently have two UITableViews populated with contacts for the app. I have one for simply viewing them and editing/deleting and one for searching/picking contacts from a list. However, I'm getting a returned nil value when trying to use the same custom class cell for both UITableViews.
These are my two cellForRowAtIndexPath functions.
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCellWithIdentifier("SecondCell") as! ContactCell
let item = contacts[indexPath.row]
cell.meetupLabel?.text = item.fullName
return cell
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCellWithIdentifier("FirstCell") as! ContactCell
let item = contacts[indexPath.row]
cell.label?.text = item.fullName
return cell
}
If the table did not have a cell named FirstCell or SecondCell, the dequeueReusableCellWithIdentifier(_:) method will return nil, and you will need to construct the cell yourself.
// no don't do this.
let cell: ContactCell
if let c = tableView.dequeueReusableCell(withIdentifier: "FirstCell") as? ContactCell {
cell = c
} else {
cell = ContactCell(style: .default, reuseIdentifier: "FirstCell")
}
You should use dequeueReusableCell(withIdentifier:for:), which was introduced in iOS 6, if you would like UIKit to construct the cell for you:
// swift 3
let cell = tableView.dequeueReusableCell(withIdentifier: "FirstCell",
for: indexPath) as! ContactCell
// swift 2
let cell = tableView.dequeueReusableCellWithIdentifier("FirstCell",
forIndexPath: indexPath) as! ContactCell
...
Also, check if you have given the correct reuse-identifiers to the cells correctly in the interface builder.
As you said you are getting nil, my quick guess is that you haven't registered the cell at some point, runs earlier than this cell event. Look at this thread on how to register cell.
I am building a custom UITableView with custom cells.
Each of the custom cells are a subclass of FormItemTableViewCell
I am attempting to populate the cell data in cellForRowAtIndexPath
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = FormItemTableViewCell();
if(indexPath.row == 1){
cell = tableView.dequeueReusableCellWithIdentifier(twoOptionCellIdentifier, forIndexPath: indexPath) as! TwoOptionTableViewCell
} else {
cell = tableView.dequeueReusableCellWithIdentifier(oneTextFieldCellIdentifier, forIndexPath: indexPath) as! OneTextFieldTableViewCell
}
cell.questionLabel.text = "What is the meaning of life?";
return cell
}
How do I access the elements in the subclass?
For example: TwoOptionTableViewCell has a segControl
while the OneTextFieldTableViewCell has a answerTextField
There are some decent answers in this question but most of them have one bad thing in common, they force unwrapped optionals, which you should avoid as much as you can (pretty much the only acceptable place to use them is in IBOutlets)
This is what I think is the best way to handle this:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCellWithIdentifier("Identifier", forIndexPath: indexPath) as? FormItemTableViewCell else {
fatalError("Cell is not of kind FormItemTableViewCell")
}
switch cell {
case let cell as TwoOptionTableViewCell where indexPath.row == 1:
// Configure cell, which is an object of class TwoOptionTableViewCell, but only when we are in row 1
break
case let cell as TwoOptionTableViewCell:
// Configure cell, which is an object of class TwoOptionTableViewCell, when the row is anything but 1
break
case let cell as OneTextFieldTableViewCell:
// Configure cell, which is an object of class OneTextFieldTableViewCell
break
case _: print("The cell \(cell) didn't match any patterns: \(indexPath)")
}
cell.questionLabel.text = "What is the meaning of life?";
return cell
}
Now let me walk you through the reasons I think it's the best way.
First of all, it doesn't force unwraps any optionals, everything is unwrapped nicely in the switch case.
It dequeues your cell from the table (something you should always do) and makes sure it's a subclass of FormItemTableViewCell, otherwise it throws a fatal error.
By using a switch case, it casts cell into the class you need, and at the same time it checks if it's the index path you want. So if you want to share some logic in different rows that share a class, you can compare indexPath.row to multiple values. If you don't use the where clause, it will use the same logic in all places where it finds a cell with that class.
Do note that you will need to add some logic to get the desired identifier depending on the row.
You can use one of the two approaches:
1) The best way:
if(indexPath.row == 1) {
let cell = tableView.dequeueReusableCellWithIdentifier(twoOptionCellIdentifier, forIndexPath: indexPath) as! TwoOptionTableViewCell
// the type of cell is TwoOptionTableViewCell. Configure it here.
return cell
} else {
let cell = tableView.dequeueReusableCellWithIdentifier(oneTextFieldCellIdentifier, forIndexPath: indexPath) as! OneTextFieldTableViewCell
// the type of cell is TwoOptionTableViewCell. Configure it here.
return cell
}
2) If you declare cell just once, as a superclass, then you have to downcast it like this.
var cell: FormItemTableViewCell
cell = ... // dequeue and assign the cell like you do in your code.
if let twoOptionCell = cell as? TwoOptionTableViewCell
{
// configure twoOptionCell
}
else if let oneTextFieldCell = cell as? OneTextFieldTableViewCell
{
// configure oneTextFieldCell
}
return cell
This is more verbose, once you add the code to dequeue the cell. So I personally prefer and recommend the first approach.
If I understand correctly, you want to keep main declaration of cell as FormItemTableViewCell to access common properties.
You can create a new variable and assign it the casted version.
Do your stuff with this instance as this is a class object it will point to same reference.
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = FormItemTableViewCell();
// this can be replaced with below line as I don't see the purpose of creating an instance here while you use dequeue below.
// var cell: FormItemTableViewCell!
if(indexPath.row == 1){
cell = tableView.dequeueReusableCellWithIdentifier(twoOptionCellIdentifier, forIndexPath: indexPath);
let tempCell = cell as! TwoOptionTableViewCell;
// access members of TwoOptionTableViewCell on tempCell
tempCell.segControl.someProperty = 0;
} else {
cell = tableView.dequeueReusableCellWithIdentifier(oneTextFieldCellIdentifier, forIndexPath: indexPath);
let tempCell = cell as! OneTextFieldTableViewCell;
// access members of OneTextFieldTableViewCell on tempCell
tempCell.answerTextField.text = "42";
}
cell.questionLabel.text = "What is the meaning of life?";
return cell
}
You're going to have to conditionally cast them in that case. I like using Enums for Rows/Sections instead of == 1 (depending on how your TableView is setup), but basically you'll want to do the following:
if indexPath.row == 1 {
let cell = tableView.dequeueReusableCellWithIdentifier(twoOptionCellIdentifier, forIndexPath: indexPath) as! TwoOptionTableViewCell
// Note that we cast the cell to TwoOptionTableViewCell
// access `segControl` here
return cell
} else {
let cell = tableView.dequeueReusableCellWithIdentifier(oneTextFieldCellIdentifier, forIndexPath: indexPath) as! OneTextFieldTableViewCell
// This cell we cast to OneTextFieldTableViewCell.
// access `answerTextField` here
return cell
}
What you were doing was defining the cell as FormItemTableViewCell, so subsequent accesses would only know it in that form even though you explicitly cast it to a subclass during assignment.
As a side-note, you don't have to assign to the var as you did there, what you could do is let cell: FormItemTableViewCell. Then in the if-statements you could define new cells of the subclasses, operate on them, and then assign back to your original cell and then return that. This is useful if you're going to be performing the same operations on both cell types after the if statements (such as setting a background colour or something, regardless of which subclass you have).
Here is my favourite way of handling this situation:
enum CellTypes {
case TwoOption, OneTextField
init(row: Int) {
if row == 1 {
self = .TwoOption
} else {
self = .OneTextField
}
}
var reuseIdentifier: String {
switch self {
case .TwoOption: return "twoOptionReuseIdentifier"
case .OneTextField: return "oneTextFieldReuseIdentifier"
}
}
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: FormItemTableViewCell
let cellType = CellTypes(row: indexPath.row)
switch cellType {
case .TwoOption:
let twoOptionCell = tableView.dequeueReusableCellWithIdentifier(cellType.reuseIdentifier, forIndexPath: indexPath) as! TwoOptionTableViewCell
// do stuff with the `segControl`
cell = twoOptionCell
case .OneTextField:
let textFieldCell = tableView.dequeueReusableCellWithIdentifier(cellType.reuseIdentifier, forIndexPath: indexPath) as! OneTextFieldTableViewCell
// do stuff with the `answerTextField`
cell = textFieldCell
}
// Here do something regardless of which CellType it is:
cell.questionLabel.text = "What is the meaning of life?"
return cell
}
I have a collection view which looks like
1st cell will hold some text , and from 2nd cell onwards data is populated from a data manager
To handle this i have code something like this
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
if(indexPath.row==0){
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(customCellNibName, forIndexPath: indexPath)
let offer: TGOfferDataSource? = dataSource?.dataforIndexPath(indexPath) as? TGOfferDataSource
cell.setOfferData(offer!)
return cell
}
else if(indexPath.row != 0)
{
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellNibName, forIndexPath: indexPath)
let product: TGProductDataSource? = dataSource?.dataforIndexPath(indexPath) as? TGProductDataSource
cell.setProductData(product!)
return cell
}
}
The issue is 1st product from data manager is hidden behind this grey cell.
So i figure i will have to increment index path in elseif part. Something like indexPath in elseif part should also starts from 0.
(Swift and cells are xib)
Any idea how to do it ?
Thanks
Had a look at this but how to do this in swift
EDIT
If I remove if part , it looks like
You can create new NSIndexPath in swift using following
let path = NSIndexPath(forRow: indexPath.row - 1, inSection: indexPath.section)
And you can pass above path to your dataforIndexPath in the else part. Hope that helps!