Using UITableView with one Prototype cell inside a ContainerView. The table will need to provide cells so that at run time, the code will add different views in different cells for user information and interaction.
The connection is made between the tableView and the containerView.swift to be its dataSource and delegate.
In the containerView.swift, the UIViewController has been extended.
extension myContainerView: UITableViewDataSource, UITableViewDelegate {...}
And in that block of code, there are required func which return numberOfRowsInSection and cellForRowAtIndexPath
But these infos are available at run time and thus my code is not complying now, I get this following error when return parent.mainTbRowCount() is reached, and if I return just a dummy int for now, I get the same error when let view = parent.cellsViewsDesider.views![indexPath.row] is reached.
fatal error: unexpectedly found nil while unwrapping an Optional value
extension myContainer: UITableViewDataSource, UITableViewDelegate {
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return parent.mainTbRowCount() // <------ fatal error
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("topCellId", forIndexPath: indexPath)
let view = parent.cellsViewsDesider.views![indexPath.row] // <---- fatal error
cell.contentView.addSubview(view!)
return cell
}
If I delete the connection which I made between the tableView and the containerView.swift to be its dataSource and delegate, the code compiles but the functions for numberOfRowsInSection and cellForRowAtIndexPath never get called.
What needs to be done in this case?
Thank you
Related
I have a table view controller that needs to be updated through a delegate call. I have set the datasource and delegate and on initial load of the tableview, all works as expected. I have a delegate method that gets called after a datasource update. The delegate calls a refresh method in the table view controller class which calls .reloadData()
When reloadData is called, numberOfRowsInSection is called and accurately returns the number of rows, however cellForRowAtIndexPath never gets called.
In this particular case, numberOfRowsInSection returns 2, therefore cellForRowAtIndexPath should be called twice but it's called zero times.
On initial load everything is fine. It's only when reloadData is called taht cellForRowAtIndexPath is ignored. I have done this same thing many times in Obj-C without any weirdness. Are there any known issues with this in Swift?
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier(LayerMenuCell.reuseId) as! LayerMenuCell
// ....
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(layerEntries?.count)
return (layerEntries?.count)!
}
func refresh() {
self.layersTableView.reloadData()
}
Thanks!
Try setting the delegate and dataSource of your UITableView:
myTable.delegate = self
myTable.dataSource = self
As specified in the Documentation:
A functioning table view requires three table view data source
methods.
func numberOfSectionsInTableView(tableView: UITableView) -> Int
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
MAake sure you implement the above three delegate methods and they return some values other than nil or 0.
There is a chance that cell height could be 0/ table height is 0 in both the cases cell for row method will not get called.
Also make sure you set the delegate properly and call the reloadData method on main thread. More on here
Things you need to check when Tableview is not working as expected:
1. Setting the delegate and datasource through storyboard or by code.
self.tableView.delegate = self
self.tableView.dataSource = self
2.check if tableView in storyboard is connected to tableView outlet.
3.check numberOfRowsInSection and numberOfSectionsInT‌​ableView returning the correct values.
4.check if the methods is written properly.
5.add the delegate and datasource after UIViewController.
<UITableViewDelegate , UITableViewDataSource>
this will help you if you are missing any thing.
I'm just starting with Swift and xCode, and currently messing around with UITableView, I can't manage to just write 'test' into a table.
I created a UITableViewController in the Storyboard, specified a custom class for it (my swift file below), filled in 'ClientCell' as a reuse identifier of the cell and the code is as follows:
class TableViewController: UITableViewController {
#IBOutlet var clientTable: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
clientTable.dataSource = self.dataSource;
clientTable.delegate = self;
}
func numberOfRowsInSection(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("ClientCell", forIndexPath: indexPath) as! CustomTableViewCell
cell.tableLabel.text = "test"
return cell
}
}
In the storyboard, I added a 'UILabel' into the prototype cell, and created an outlet for it named 'tableLabel' in the CustomTableViewCell.swift.
I confused by all the side-things I've to consider when doing something as simple as this.
When I run it, the simulator just shows a table with a lot of horizontal lines, but nowhere it says 'test'.
You haven't used the numberOfRowsInSection method.....
Additionally you also need to set the table view's data source and delegate to be the class you are writing these methods in (in case you haven't).
At a bare minimum you need this:
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1 // this should really be from your data source
}
If you create a UITableViewController subclass in Xcode the template will have commented-out versions of all the methods you likely will want to fill out.
I'm starting to work with UITableViews and can't seem to find out how to change the position of a cell with code. Changing the position in the storyboard is straightforward enough but I need to be able to do it in swift.
TLDR;
Update your data. i.e. swap(&arr[2], &arr[3]).
Call the tableView's reloadData() method to reflect the changes to your data.
Long answer
An instance of UITableView works by checking its data source (UITableViewDataSource) for the information it needs. This includes the number of sections and rows, as well as the instance of UITableViewCell that the table view is to use. These are defined by the following UITableViewDataSource delegate methods:
override func numberOfSectionsInTableView(tableView: UITableView) -> Int;
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int;
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell;
Usually, you would base the former two on some data you have, likely an Array or similar container. For example, if your tableView displayed data from an Array named fruitArray (which contained names of different fruit - a list of strings), then you might have something like the following:
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// Our array is one dimensional, so only need one section.
// If you have an array of arrays for example, you could set this using the number of elements of your child arrays
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Number of fruits in our array
return fruitArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("yourCellId") // Set this in Interface Builder
cell.textLabel?.text = fruitArray[indexPath.row]
return cell
}
Then, you can see that the answer to your question becomes simple! Since the contents of a given cell are based upon fruitArray, all you need to do is update your array. But how do you get the tableView to "recheck" its dataSource? Well, you use the reloadData method, like so:
swap(&fruitArray[2], &fruitArray[3])
tableView.reloadData()
This then triggers the tableView to "recheck" its dataSource, hence causing your data swap to appear on the screen!
If you'd like the user to be able to swap the positions of the cells, you can use the following UITableViewDelegate (not UITableViewDataSource) delegate method:
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool
Have a look at this article for more info. You can also view Apple's documentation on UITableView, UITableViewDataSource, and UITableViewDelegate for further detail.
Hope this helps!
I have a ViewController that calls (clicking on a button) another View using this function
#IBAction func btnSeeContact(sender: AnyObject) {
self.performSegueWithIdentifier("segueSeeContact", sender: self)
}
and my prototype cell is "linked" to a custom View Controller named ContactsTableViewCell that I have created and it implements:
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! ContactsTableViewCell
cell.txtName.text = "test"
cell.txtPhone.text = "1234567890"
return cell
}
When I run the project, the button calls the table, but there is no Cell on it, and I put a breakpoint on those tableView functions and they are not being reached.
What am I missing here that those functions are never being called?
I am adding a new answer since my previous answer was up voted, so I don't want to make massive edits that one, and is still a valid way to fix your issue.
The issue is you have your custom classes confused. In your screen shot you can see that the the Table View Controller is not set to a custom class, it just says Table View Controller. That is the object that needs to get a custom implementation of the UITableViewController class.
Instead you seem to be setting the cell's class to a custom class, and implementing the delegate methods there. You still need a custom class for the table view cell, but it should be a custom class of UITableViewCell.
So your cell class should look something like this:
import UIKit
class YourCustomTableViewCell: UITableViewCell {
#IBOutlet weak var yourLabel1: UILabel!
#IBOutlet weak var yourLabel2: UILabel!
}
You will be given an instance of this cell to configure in cellForIndexPath.
So your Table view controller class should be set to a class that looks like below. The YourTableViewController is were you want to implement all the delegate methods.
Note: if you are using a UITableViewController dragged out from the storyboard, it will already have the tableView, and delegate / data source stuff already wired up for you. You will also notice that you are overriding the delegate methods as the UITableViewController class has default implementations of these. If you are just using a normal view controller, then see my previous answer for more details on how to set that up.
import UIKit
class YourTableViewController: UITableViewController {
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 1
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath)
if let cell = cell as? YourCustomTableViewCell {
cell.yourLabel1.text = "some text"
cell.yourLabel2.text = "some other text"
}
return cell
}
}
As others have commented, you really need to provide a little more context.
Here are a few things that might be going wrong, providing more context would confirm or deny this guesses.
First you don't show the numberOfSectionsInTableView method.
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 0
}
I think you would need to provide a value other than 0
Secondly, since I don't see override in front of what I am sure you are intending to be UITableViewDelegate methods function calls, that means your view controller is not a UITableViewController. This makes me wonder if you defined this view controller as conforming to the UITableViewDelegate protocol and if you set the table view outlet delegate to self. (or even wired up the UITableView to an outlet)
If you use a plain UIViewController to host a table view you need to do the following:
Wire up your UITableView to an outlet in your view controller
Declare the view controller as conforming to the UITableViewDeleagate (and maybe UITableViewDataSource) protocol
set the table view's outlet delegate (and maybe dataSource) properties to self (the view controller implementing the protocols)
Implement the required methods
So something like this:
class MyTableViewController: UIViewController, UITableViewDelegate {
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 1
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("your PrototypeCell", forIndexPath: indexPath)
// Configure the cell...
return cell
}
}
I'm learning Swift and, coding some lines, an error appear on the screen showing: Type JVViewController (class name) does not conform to protocol 'UITableViewDataSource'. I don't know why this appear in my file if I did exactly the same in other apps and I never did this kind of problem.
Please, let me know how to solve this situation.
Thanks!
If a class does not conform with a protocol, it means you need to implement some protocol methods. In case on the UITableViewDataSource, is required to implement the follow methods:
It defines the quantity of tableViewCell you will show on your tableView
tableView(_:numberOfRowsInSection:)
It defines the settings of each tableViewCell
tableView(_:cellForRowAtIndexPath:)
Maybe you forgot to implement one or this two dataSource methods.
E.g.:
class JVViewController : UIViewController, UITableViewDelegate, UITableViewDataSource {
...
var collectionItems = ["One", "Two", "Three"]
...
//Quantity of rows
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.collectionItems.count;
}
//Row settings
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell:UITableViewCell = self.tableView.dequeueReusableCellWithIdentifier("cell") as UITableViewCell
cell.textLabel?.text = self.collectionItems[indexPath.row]
return cell
}
...
}
You can find out more in Apple documentation: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITableViewDataSource_Protocol/