I have an iPad TabBar navigation app and in OrderViewController I have a tableview on left side and outlets on the right side of the view as in a sort of split view controller. When you click a tableView's cell it shows details on the other half screen. As I'm introducing two different color schemes for A/B testing, I use a switch to perform the change in color. The color switching dough doesn't succeed with tableView's cells. Adding a reloadData() in viewWillAppeardidn't solve the problem.
Everything gets updated except for the cells, they maintain the colors of when they got created the first time.
I added prints throughout the phases and I detected that cell's awakeFromNimbgets called only the first time. How do I get it to be called on tableView.reloadData()? As always many thanks.
awakeFromNib():
override func awakeFromNib() {
super.awakeFromNib()
configureUi()
}
viewWillAppear():
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
self.configureFetchedResultsController()
orderTableView.delegate = self
orderTableView.dataSource = self
configureUI()
orderTableView.reloadData()
}
Use the tableView delegate willDisplayCell
https://developer.apple.com/documentation/uikit/uitableviewdelegate/1614883-tableview
class MyCustomVC: UITableViewDelegate {
override func tableView(_ tableView: UITableView,
willDisplay cell: UITableViewCell,
forRowAt indexPath: IndexPath) {
guard var cell = tableView.dequeueReusableCell(withIdentifier: "yourReuseIdentifier", for: indexPath) as? YourCustomCell else {
return UITableViewCell()
}
cell.configureUi()
}
}
Related
I am new to swift and I have this app in mind that basically needs to update all the cells based on the data received from one of the cells.
I am using dynamic cells and each one has a textfield inside.
TableViewController.swift:
import UIKit
class MyCells: UITableViewCell{
#IBOutlet weak var value_textfield: UITextField!
}
class TableViewController: UITableViewController {
var units_length: [String] = ["Centimeter", "Meter", "Foot"]
override func viewDidLoad() {
super.viewDidLoad()
units_length = units_length.sorted()
self.tableView.keyboardDismissMode = .onDrag
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return units_length.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = units_length[indexPath.row]
cell.textLabel?.textColor = UIColor.white
cell.textLabel?.font = UIFont(name:"DINAlternate-Bold", size:30)
return cell
}
override func viewWillAppear(_ animated: Bool){
tableView.rowHeight = 100
}
}
Which function should I use to access all the cells with different identifiers and simultaneously update all the textfield inside each cell?
I do have access to the textfield by having another class called MyCells, how should I implement it?
(I will not include the base ViewController class here as there's nothing inside)
Thanks!
Normally you use the function you already showed: cellForRowAt. You update your model data, tell the table to reloadData, cellForRowAt is called for all visible cells, and their values become the new values.
However if you are updating after every character, I would set up a notification broadcast situation and update all visible text fields and the model together without a reload. Just make sure the model and the table stay in sync in case the user scrolls and cellForRow is called.
I am building a recorder app that users can save their recordings.
How can I change a view of a certain cell in a UITableView to show users that this cell is being played and the cell with the same content in other ViewControllers can be changed simultaneously?
Furthermore, when the audio player finished. The view can be changed back to default.
I have tried override setSelected, but the cell cannot stay selected when I reload the table view and the cell cannot be deselected by itself when audio has finished. I also cannot change the cell with the same content (same audio)' view simultaneously.
Is there a way to overcome this problem?
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
if selected {
print("task has began")
} else if !selected {
print("task has finished")
}
}
The result will be like apple music or podcast that the cell with the same shows across the app will show whether or not it is being played.
First make IBOutlet of View Inside xib
class TableViewCell: UITableViewCell {
#IBOutlet weak var generaV: UIView!
}
set Identifier = TableViewCell
and call the Datasource Method in as many file you want and change the color like .red/.blue in in different VC
Call the Cell in ViewController
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath) as! TableViewCell
if (audioEnded){
cell.generaV.backgroundColor = UIColor.green
}
else {
cell.generaV.backgroundColor = UIColor.red
}
return cell
}
I have UITableView in a test project that is created this way:
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
tableView.delegate = self
tableView.dataSource = self
}
// height?
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
//return cellHeightWithoutSeparator + cellSeparatorHeight
//print("YES!")
return 80 // arbitrary
}
// table wants a UITableViewCell for each row
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! CustomCell
// customize cell here
return cell
}
// how many rows?
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 50 // arbitrary
}
}
The structure of the table view is:
So, as you can see the cell contains a button.
I want the button (or any clickable view that is a subview of the cell) to respond immediately to the touch-down event and so I unchecked "Delay Touch Down" in the ScrollView property inspector in the storyboard.
It is my understanding that unchecking that box is equivalent to the code:
tableView.delaysContentTouches = false
According to the docs, this method is supposed to work on IOS 2.0+
But setting this property true or false only works as expected on IOS 11 and 12, but on IOS 10 (and presumably earlier), it is as if the box was never unchecked and touches on the button are still delayed.
I understand that it is still possible to make views "clickable" in the cell, and respond immediately to "touch up inside," (because the touch-up event will cancel the delay on the touch-down), but I still want the touch down event to call immediately (on all iOS versions, not just 11+) because:
1) I want the re-order control to respond immediately.
2) I want to have visual feedback for touch-down be normal/immediate on views in the cell.
I have also consulted this similar, but not the same, question which was written 4 years ago, and I tried applying the answers, but none of those answers seem to apply to whatever the modern day reason for this problem is.
Does anyone know the cause and (preferably Swift) solution to this?
The problem I'm facing is probably some lack of understanding on the concept of reusable cells. I have, let's say, 30 rows to be created and each of them has a UISwitch.
When I toggle one of the switches, it's behavior should affect the other 29. The point is: as far as I know, iOS doesn't create all of them at once, but rather wait to reuse the cells when the TableView is scrolled up and down.
How can I keep a copy of those reused objects and tell iOS to set the proper value to the switches?
I've thought on having the cells appended to a [UISwitch] but I can't manage to have all the 30 cells in there, look:
...
var switches = [UISwitch]()
...
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Field10Cell", for: indexPath) as! Field10TableViewCell
...
//cell.value is a UISwitch
if !switches.contains(cell.value) {
switches.append(cell.value)
}
return cell
}
You could create a set which stores the indexes of the cells whose switches have been pressed.
var activeSwitches = Set<IndexPath>()
Whenever a user presses the switch on a cell, you store it on the set like this:
activeSwitches.insert(indexPath)
If you need to check if a switch was activated, just check if its container cell's indexPath is in active switches like so:
if activeSwitches.contains(indexPath) {
// do something
}
In order to know when a user pressed a specific switch I recommend the folliwing:
In cellForRowAtIndexPath save the current indexPath into your Field10TableViewCell.
Create a protocol on Field10TableViewCell and add a delegate.
protocol Field10Delegate {
func didChangeSwitch(value: Bool, indexPath: IndexPath)
}
class Field10TableViewCell {
var delegate: Field10Delegate?
var indexPath: IndexPath?
#IBOutlet weak var fieldSwitch: UISwitch! // Can't use 'switch' as a variable name
#IBAction func switchValueChanged(_ sender: UISwitch) {
if let indexPath = indexPath {
delegate?.didChangeSwitch(value: sender.isOn, indexPath: indexPath)
}
}
When you create a cell, set the view controller as a delegate
let cell = tableView.dequeueReusableCell(withIdentifier: "Field10Cell", for: indexPath) as! Field10TableViewCell
cell.delegate = self
cell.indexPath = indexPath
Make your view controller comply with the protocol:
extension ViewController: Field10Delegate {
/* Whenever a switch is pressed on any cell, this delegate will
be called. This is a good place also to trigger a update to
your UI if it has to respond to switch changes.
*/
func didChangeSwitch(value: Bool, indexPath: IndexPath) {
if value {
activeSwitches.insert(indexPath)
} else {
activeSwitches.remove(indexPath)
}
updateUI()
}
}
With the above, at any point you will know which switches are active or not and you can process the dequeued cells with this information.
This is the flow of my app:
First, the TableView is set to hidden. There is a UITextField in the center of the screen. When the user types something and hits Go, this code is run:
self.view.layoutIfNeeded()
UIView.animateWithDuration(0.5, animations: {
self.textFieldConstraint.constant = -230
self.tableView.hidden = false
self.goButton.hidden = true
self.view.layoutIfNeeded()
}, completion: nil)
At this point, the tableview is populated. When a row is selected, I need to manipulate the data that is populating it.
However, absolutely nothing happens when I tap a cell.
What am I doing wrong?
My TableView code is here:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: SearchResultsTableViewCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! SearchResultsTableViewCell
cell.label.text = searchResultsNames[indexPath.row]
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return searchResultsUrls.count
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
print("HELLO")
}
And, I have set the dataSource and delegate properly.
I also want to clarify that the tableView populates and scrolls properly; it just won't do anything when I tap a cell.
Update:
I've discovered that for some reason, I can select the cells when I press and hold them. It is not what I want, so does anybody know how to fix this?
I have just used your code to create a simple table, selection is working fine and logging out HELLO as expected. Can you check the values of Selection in the attributes inspector? Here is mine, which has Selection set to Single Selection.
And here is the code I used for my simple table
import UIKit
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var tableView: UITableView!
var searchResults = [String]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
searchResults.append("Testing 1")
searchResults.append("Testing 2")
searchResults.append("Testing 3")
searchResults.append("Testing 4")
searchResults.append("Testing 5")
tableView.dataSource = self
tableView.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("tableCell", forIndexPath: indexPath)
cell.textLabel?.text = searchResults[indexPath.row]
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return searchResults.count
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
print("HELLO")
}
}
I also tried hiding and showing the tableView which made no difference on selection.
EDIT & SOLUTION:
In the comments below, we discovered that the issue is related to a tapGestureRecogniser on the view, This was identified by the op only being able to make a selection by holding a tap on the cell. The gesture has to fail before the selection can be made, the op managed to solve the problem by referring to this other SO Answer
if you use "tap" gesture, you can't select table cell. (but, if you click and drag to right a cell, you can select it.)
Check gesture first.
And if your code has self.tableView.allowsSelection = false, replace false to true or delete this line.
My problem has been caused by the tap gesture recognizer on the view controller itself (I had BaseTableViewController I was extending from). Probably it was interfering with the gesture recognizers of UITableView.
In your viewDidLoad, or wherever you set up your view, make certain that your table view even allows selections. That can be controlled with the allowSelection property.
Something like:
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.allowsSelection = true
}
If you have a gesture recognizer, just type gestureRecognizer.cancelsTouchesInView = false
For me I was implementing another did select row method, so I erased it and typed "didSelect..." and selected the first one in the suggested methods, which is this for swift 3:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("Row #: \(indexPath)")
}
Try disabling and then enabling the user interaction Enabled property in the attribute inspector of your tableView
Looks something like this
I met the same problem as you and solved it by removing the below code
self.view.layoutIfNeeded()
you can try it.