I need to access to the particular cell and change its content dynamically on didSelectAt indexPath
func collectionView(_ collectionView: UICollectionView,
didSelectItemAt indexPath: IndexPath) {
if collectionView == self.trendHeaderView{
print(indexPath.row)
// Needs to access cell and change the
// content of cell i.e label text inside cell ??
}
}
I need to access to the particular cell
No, you don't. You should never meddle with a cell's contents directly. You need to access the data (the "model") that the collection view's data source is using. And you can easily do that, because you have the indexPath. Change the data, and reload the collection view so that it picks up the changes and displays them.
You can't change the cell's content directly in didSelectItemAt.
As you can see, in UICollectionView cell is reused by calling dequeReusableCell.
So I think, it's good to make model for that.
and change the model content in didSelectItemAt.
and Please call reloadData to redraw collectionview.
I have an ImageView in my TableView Cell xib, I want to access this image view in my viewController but i don't want to make an outlet of imageView i.e. in my cell as i can access my Cell in ViewController ,so how can i make access to the image view.
Thanks in advance
I assume you're wanting to find the imageView in your code's cellForRowAt function, so that you can set its image.
In the design of the cell, give the UIImageView a tag (eg. 7). Then within your code after you have retrieved the cell, you can find the imageView using:
let imageView = cell.viewWithTag(7) as! UIImageView
I am new to IOS/IOX development. I tried many sites to load data to my table on OSX swift using NSTableView. But all was failure.
The procedure i did was refering View-Based NSTableView in Swift - How to
Drag and droped a NSTableView, which was perfectly seen when I run the code.
Selected the first column and gave Identifier as "List" after setting number of columns to 1
In the appdelegate.swift I pasted as
class AppDelegate: NSObject, NSApplicationDelegate,NSTableViewDataSource,NSTableViewDelegate {
func applicationDidFinishLaunching(aNotification: NSNotification?) {
}
func applicationWillTerminate(aNotification: NSNotification?) {
}
func numberOfRowsInTableView(aTableView: NSTableView!) -> Int {
println("reached 1")
return 10
}
func tableView(tableView: NSTableView, viewForTableColumn: NSTableColumn, row: Int) -> NSView {
println("reached 2")
var cell = tableView.makeViewWithIdentifier("List", owner: self) as NSTableCellView
cell.textField.stringValue = "Hey, this is a cell"
return cell
}
}
Then i tried to Set the delegate and datasource as the Appdelegate for the table view by selecting table and pointing to "App Delegate" in "Application Scene". But it was not linking
When i run the program , table with no cells was loaded
Any help is greatly appreciated.
The easiest way would be selecting your table view in the XIB file and then in the Utilities panel on the right chose the third icon from the right (the arrow pointing right). Also make sure you show the document outline by clicking the icon in the lower left of the Interface Builder window. From the Utilities panel you can just drag from the delegate and datasource circle to your AppDelegate in the document outline.
func tableView(tableView: NSTableView, viewForTableColumn tableColumn: NSTableColumn?, row: Int) -> NSView?
{
if tableView.identifier=="tableViewIdentifier" {
let cellView = tableView.makeViewWithIdentifier("List", owner: self) as! NSTableCellView
cellView.textField?.stringValue = "Hey, this is a cell"
return cellView
}
return nil
}
set identifier to tableview of dropped table also set identifier to table column, set the delegate and datasource to the view controller in which the table is contained.
In your case, when using storyboards, you should make your view controller a data source and delegate for your table view, because they're contained in one scene. The class itself is called ViewController in Xcode project templates.
So, just move the code from application delegate to view controller and connect all the things in storyboard.
I have a UICollectionView with a supplementary view -- in essence a header for the collection. Whenever I add a gesture recognizer to a UILabel within the headerView.xib using the interface builder, the app crashes giving me
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'invalid nib registered for identifier (MY_HEADER) - nib must contain exactly one top level object which must be a UICollectionReusableView instance'
What is preventing me from adding a gesture recognizer to a UILabel within a supplementary view of a UICollectionView?
So it looks like you cannot use the interface builder to add a gesture recognizer to a supplementary view of a UICollectionView.
I believe this is because when the .xib's are loaded, the UICollectionView must appear as one thing to the superview -- and when you add the gesture recognizer to that UICollectionView you end up with two things at the superview level, which both correspond to the UICollectionView.
You can however implement your gesture recognizer programmatically using the definition of your supplementary view inside of the UICollectionViewReusableView Protocol. (The if is being used to distinguish between a header supplementary view and an footer supplementary view later in the code)
if (kind == UICollectionElementKindSectionHeader) {
MyHeaderView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:#"MY_HEADER" forIndexPath:indexPath];
// call headerView methods (to put things into the header's UI objects for example)
[headerView ...];
[headerView ...];
[headerView ...];
// add gesture recognition for tapping on a UIlabel within the header (UICollectionView supplementary view)
UITapGestureRecognizer *bioTap = [[UITapGestureRecognizer alloc] initWithTarget:headerView action:#selector(handleUILabelTap:)];
// make your gesture recognizer priority
bioTap.delaysTouchesBegan = YES;
bioTap.numberOfTapsRequired = 1;
[headerView.UILabelName addGestureRecognizer:UILabelTap];
reusableview = headerView;
}
I too have not been able to add a gesture to a cell via IB.
However, my experience has been that using IB you CAN add a gesture recognizer to the collectionView itself by dragging one to the collectionView item in the outline view NOT to the scrollView that lies on top of the collectionView in the graphical representation.
So far I can only get a single tap through the cell and into the collectionView.
I add gesture recognizer when the supplementary view has been loaded from nib.
class MySuppleMentaryView: UICollectionReusableView
{
#IBOutlet var label: UILabel!
weak var delegate: MySuppleMentaryViewDelegate!
override func awakeFromNib() {
super.awakeFromNib()
// NOTE: UILabel MUST enable user interaction to receive touch events.
// label.isUserInteractionEnabled = true
let tap = UITapGestureRecognizer(target: self, action: #selector(onClickLabel))
tap.delaysTouchesBegan = true
tap.numberOfTapsRequired = 1
self.label.addGestureRecognizer(tap)
}
#objc func onClickLabel() {
self.delegate.didOnLabel(cell: self)
}
}
protocol MySuppleMentaryViewDelegate: NSObjectProtocol {
func didOnLabel(cell: DCScheduleHourLabel)
}
// Configure supplementary cell
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
if (kind == UICollectionElementKindSectionHeader) {
// NOTE: The cell might be reused.
// If gesture recognizer is added HERE,
// then maybe multiple gesture recognizers are added when reusing the cell.
let cell = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: DCScheduleDummyBlock.Identifier, for: indexPath) as! MySuppleMentaryView
// configure cell
cell.delegate = self
return cell
}
return UICollectionReusableView()
}
How about adding it programmatically after the nib's loaded? alternatively, in IB have you tried moving the location of the icon that represents the recognizer above or below that which represents the view
I'm trying to use storyboards in an app I'm working on. In the app there are Lists and Users and each contains a collection of the other (members of a list, lists owned by a user). So, accordingly, I have ListCell and UserCell classes. The goal is to have those be re-usable throughout the app (ie, in any of my tableview controllers).
That's where I'm running into a problem.
How do I create a custom tableview cell in the storyboard that can be re-used in any view controller?
Here are the specific things I've tried so far.
In Controller #1, added a prototype cell, set the class to my UITableViewCell subclass, set the reuse id, added the labels and wired them to the class's outlets. In Controller #2, added an empty prototype cell, set it to the same class and reuse id as before. When it runs, the labels never appear when the cells are shown in Controller #2. Works fine in Controller #1.
Designed each cell type in a different NIB and wired up to the appropriate cell class. In storyboard, added an empty prototype cell and set its class and reuse id to refer to my cell class. In controllers' viewDidLoad methods, registered those NIB files for the reuse id. When shown, cells in both controllers were empty like the prototype.
Kept prototypes in both controllers empty and set class and reuse id to my cell class. Constructed the cells' UI entirely in code. Cells work perfectly in all controllers.
In the second case I suspect that the prototype is always overriding the NIB and if I killed the prototype cells, registering my NIB for the reuse id would work. But then I wouldn't be able to setup segues from the cells to other frames, which is really the whole point of using storyboards.
At the end of the day, I want two things: wire up tableview based flows in the storyboard and define cell layouts visually rather than in code. I can't see how to get both of those so far.
As I understand it, you want to:
Design a cell in IB which can be used in multiple storyboard scenes.
Configure unique storyboard segues from that cell, depending on the scene the cell is in.
Unfortunately, there is currently no way to do this. To understand why your previous attempts didn't work, you need to understand more about how storyboards and prototype table view cells work. (If you don't care about why these other attempts didn't work, feel free to leave now. I've got no magical workarounds for you, other than suggesting that you file a bug.)
A storyboard is, in essence, not much more than a collection of .xib files. When you load up a table view controller that has some prototype cells out of a storyboard, here's what happens:
Each prototype cell is actually its own embedded mini-nib. So when the table view controller is loading up, it runs through each of the prototype cell's nibs and calls -[UITableView registerNib:forCellReuseIdentifier:].
The table view asks the controller for the cells.
You probably call -[UITableView dequeueReusableCellWithIdentifier:]
When you request a cell with a given reuse identifier, it checks whether it has a nib registered. If it does, it instantiates an instance of that cell. This is composed of the following steps:
Look at the class of the cell, as defined in the cell's nib. Call [[CellClass alloc] initWithCoder:].
The -initWithCoder: method goes through and adds subviews and sets properties that were defined in the nib. (IBOutlets probably get hooked up here as well, though I haven't tested that; it may happen in -awakeFromNib)
You configure your cell however you want.
The important thing to note here is there is a distinction between the class of the cell and the visual appearance of the cell. You could create two separate prototype cells of the same class, but with their subviews laid out completely differently. In fact, if you use the default UITableViewCell styles, this is exactly what's happening. The "Default" style and the "Subtitle" style, for example, are both represented by the same UITableViewCell class.
This is important: The class of the cell does not have a one-to-one correlation with a particular view hierarchy. The view hierarchy is determined entirely by what's in the prototype cell that was registered with this particular controller.
Note, as well, that the cell's reuse identifier was not registered in some global cell dispensary. The reuse identifier is only used within the context of a single UITableView instance.
Given this information, let's look at what happened in your above attempts.
In Controller #1, added a prototype cell, set the class to my
UITableViewCell subclass, set the reuse id, added the labels and wired
them to the class's outlets. In Controller #2, added an empty
prototype cell, set it to the same class and reuse id as before. When
it runs, the labels never appear when the cells are shown in
Controller #2. Works fine in Controller #1.
This is expected. While both cells had the same class, the view hierarchy that was passed to the cell in Controller #2 was entirely devoid of subviews. So you got an empty cell, which is exactly what you put in the prototype.
Designed each cell type in a different NIB and wired up to the
appropriate cell class. In storyboard, added an empty prototype cell
and set its class and reuse id to refer to my cell class. In
controllers' viewDidLoad methods, registered those NIB files for the
reuse id. When shown, cells in both controllers were empty like the
prototype.
Again, this is expected. The reuse identifier is not shared between storyboard scenes or nibs, so the fact that all of these distinct cells had the same reuse identifier was meaningless. The cell you get back from the tableview will have an appearance that matches the prototype cell in that scene of the storyboard.
This solution was close, though. As you noted, you could just programmatically call -[UITableView registerNib:forCellReuseIdentifier:], passing the UINib containing the cell, and you'd get back that same cell. (This isn't because the prototype was "overriding" the nib; you simply hadn't registered the nib with the tableview, so it was still looking at the nib embedded in the storyboard.) Unfortunately, there's a flaw with this approach — there's no way to hook up storyboard segues to a cell in a standalone nib.
Kept prototypes in both controllers empty and set class and reuse id
to my cell class. Constructed the cells' UI entirely in code. Cells
work perfectly in all controllers.
Naturally. Hopefully, this is unsurprising.
So, that's why it didn't work. You can design your cells in standalone nibs and use them in multiple storyboard scenes; you just can't currently hook up storyboard segues to those cells. Hopefully, though, you've learned something in the process of reading this.
In spite of the great answer by BJ Homer I feel like I have a solution. As far as my testing goes, it works.
Concept: Create a custom class for the xib cell. There you can wait for a touch event and perform the segue programmatically. Now all we need is a reference to the controller performing the Segue. My solution is to set it in tableView:cellForRowAtIndexPath:.
Example
I have a DetailedTaskCell.xib containing a table cell which I'd like to use in multiple table views:
There is a custom class TaskGuessTableCell for that cell:
This is where the magic happens.
// TaskGuessTableCell.h
#import <Foundation/Foundation.h>
#interface TaskGuessTableCell : UITableViewCell
#property (nonatomic, weak) UIViewController *controller;
#end
// TashGuessTableCell.m
#import "TaskGuessTableCell.h"
#implementation TaskGuessTableCell
#synthesize controller;
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
NSIndexPath *path = [controller.tableView indexPathForCell:self];
[controller.tableView selectRowAtIndexPath:path animated:NO scrollPosition:UITableViewScrollPositionNone];
[controller performSegueWithIdentifier:#"FinishedTask" sender:controller];
[super touchesEnded:touches withEvent:event];
}
#end
I have multiple Segues but they all have the same name: "FinishedTask". If you need to be flexible here, I suggest to add another property.
The ViewController looks like this:
// LogbookViewController.m
#import "LogbookViewController.h"
#import "TaskGuessTableCell.h"
#implementation LogbookViewController
- (void)viewDidLoad
{
[super viewDidLoad]
// register custom nib
[self.tableView registerNib:[UINib nibWithNibName:#"DetailedTaskCell" bundle:[NSBundle mainBundle]] forCellReuseIdentifier:#"DetailedTaskCell"];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
TaskGuessTableCell *cell;
cell = [tableView dequeueReusableCellWithIdentifier:#"DetailedTaskCell"];
cell.controller = self; // <-- the line that matters
// if you added the seque property to the cell class, set that one here
// cell.segue = #"TheSegueYouNeedToTrigger";
cell.taskTitle.text = [entry title];
// set other outlet values etc. ...
return cell;
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([[segue identifier] isEqualToString:#"FinishedTask"])
{
// do what you have to do, as usual
}
}
#end
There might be more elegant ways to achieve the same but - it works! :)
I was looking for this and I found this answer by Richard Venable. It works for me.
iOS 5 includes a new method on UITableView: registerNib:forCellReuseIdentifier:
To use it, put a UITableViewCell in a nib. It has to be the only root
object in the nib.
You can register the nib after loading your tableView, then when you
call dequeueReusableCellWithIdentifier: with the cell identifier, it
will pull it from the nib, just like if you had used a Storyboard
prototype cell.
BJ Homer has given an excellent explanation of what is going on.
From a practical standpoint I'd add that, given you can't have cells as xibs AND connect segues, the best one to choose is having the cell as a xib - transitions are far easier to maintain than cell layouts and properties across multiple places, and your segues are likely to be different from your different controllers anyway. You can define the segue directly from your table view controller to the next controller, and perform it in code. .
A further note is that having your cell as a separate xib file prevents you being able to connect any actions etc. directly to the table view controller (I haven't worked this out, anyway - you can't define file's owner as anything meaningful). I am working around this by defining a protocol that the cell's table view controller is expected to conform to and adding the controller as a weak property, similar to a delegate, in cellForRowAtIndexPath.
Swift 3
BJ Homer gave an excellent explanation, It helps me understand the concept. To make a custom cell reusable in storyboard, which can be used in any TableViewController we have to mix the Storyboard and xib approach. Suppose we have a cell named as CustomCell which is to be used in the TableViewControllerOne and TableViewControllerTwo. I am making it in steps.
1. File > New > Click File > Select Cocoa Touch Class > click Next > Give Name Of your class(for example CustomCell) > select Subclass as UITableVieCell > Tick the also create XIB file checkbox and press Next.
2. Customize the cell as you want and set the identifier in attribute inspector for cell, here we ll set as CellIdentifier. This identifier will be used in your ViewController to identify and reuse the Cell.
3. Now we just have to register this cell in our ViewController viewDidLoad. No need of any initialization method.
4. Now we can use this custom cell in any tableView.
In TableViewControllerOne
let reuseIdentifier = "CellIdentifier"
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(UINib(nibName: "CustomCell", bundle: nil), forCellReuseIdentifier: reuseIdentifier)
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier:reuseIdentifier, for: indexPath) as! CustomCell
return cell!
}
I found a way to load the cell for the same VC, not tested for the segues. This could be a workaround for creating the cell in a separate nib
Let's say that you have one VC and 2 tables and you want to design a cell in storyboard and use it in both tables.
(ex: a table and a search field with a UISearchController with a table for results and you want to use the same Cell in both)
When the controller asks for the cell do this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString * identifier = #"CELL_ID";
ContactsCell *cell = [self.YOURTABLEVIEW dequeueReusableCellWithIdentifier:identifier];
// Ignore the "tableView" argument
}
And here you have your cell from the storyboard
If I understand your question correctly, this is fairly easy. Create a UIViewController in your storyboard that will hold your prototype cells and create a static shared instance that loads itself from the storyboard. To handle view controller segues, use the manual segue outlet and trigger on table view delegate didSelectRow (the manual segue outlet is the middle icon at the top of the view controller in the storyboard, in between 'First Responder' and 'Exit').
XCode 12.5, iOS 13.6
// A cell with a single UILabel
class UILabelCell: UITableViewCell {
#IBOutlet weak var label: UILabel!
}
// A cell with a signle UISwitch
class UISwitchCell: UITableViewCell {
#IBOutlet weak var uiSwitch: UISwitch!
}
// The TableViewController to hold the prototype cells.
class CellPrototypeTableViewController: UITableViewController {
// Loads the view controller from the storyboard
static let shared: CellPrototypeTableViewController = {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = storyboard.instantiateViewController(withIdentifier: "cellProtoypeVC") as! CellPrototypeTableViewController
viewController.loadViewIfNeeded() // Make sure to force view controller to load the view!
return viewController
}()
// Helper methods to deque the cells
func dequeUILabeCell() -> UILabelCell {
let cell = self.tableView.dequeueReusableCell(withIdentifier: "uiLabelCell") as! UILabelCell
return cell
}
func dequeUISwitchCell() -> UISwitchCell {
let cell = self.tableView.dequeueReusableCell(withIdentifier: "uiSwitchCell") as! UISwitchCell
return cell
}
}
Use:
class MyTableViewController: UITableViewController {
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 2
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// Dequeue the cells from the shared instance
switch indexPath.row {
case 0:
let uiLabelCell = CellPrototypeTableViewController.shared.dequeUILabeCell()
uiLabelCell.label.text = "Hello World"
return uiLabelCell
case 1:
let uiSwitchCell = CellPrototypeTableViewController.shared.dequeUISwitchCell()
uiSwitchCell.uiSwitch.isOn = false
return uiSwitchCell
default:
fatalError("IndexPath out of bounds")
}
}
// Handling Segues
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
switch indexPath.row {
case 0: self.performSegue(withIdentifier: "first", sender: nil)
case 1: self.performSegue(withIdentifier: "second", sender: nil)
default:
fatalError("IndexPath out of bounds")
}
}
}