I'm trying to put checkbox to the first column of a view based tableView. I dragged a check box button to the column, then the structure is like
Table View
First Column
Check
Check
Text Cell
Then in the tableView method of the view controller I'm doing
if identifier == "Check" {
let cell = tableView.makeView(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "Check"), owner: self) as! NSTableCellView
return cell
}
I get a run time error Could not cast value of type 'NSButton' to 'NSTableCellView', what is the correct way to do it?
It's pretty simple.
In a view based NSTableView you can use any view which inherits from NSView as table cell view. The default is NSTableCellView with a text field but it's also possible to use control objects like NSTextField or NSButton without any underlying custom view just by dragging them into the table view canvas.
The error occurs because you have to cast the created view to the proper type. If you are using a checkbox cast the view to NSButton.
Don't think in terms of cell, think in terms of view. I even recommend to name the variable as view rather than as cell.
The NSUserInterfaceItemIdentifier extension is the recommended pattern to define constants
extension NSUserInterfaceItemIdentifier {
static let check = NSUserInterfaceItemIdentifier(rawValue: "Check")
}
let view = tableView.makeView(withIdentifier: .check, owner: self) as! NSButton
NSTableCellView has a imageView and a textField outlet. You need a checkbox and you can add one. Subclass NSTableCellView and add an outlet 'checkBox'. In IB, change the class of the cell view, replace the textfield by a checkbox (or add a checkbox) and connect the 'checkBox' outlet. In tableView(_:viewFor:row:), use checkBox instead of textField.
extension NSUserInterfaceItemIdentifier {
static let lhsCellImage = NSUserInterfaceItemIdentifier("lhsCellImage")
static let lhsCellName = NSUserInterfaceItemIdentifier("lhsCellName")
}
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
if tableColumn?.identifier == .lhsCellImage {
let cellView = tableView.makeView(withIdentifier: .lhsCellImage, owner: self) as! IDMainTableImageCellView
let imageNameStr = tableImageList[row]
let imageName = NSImage(named: imageNameStr as NSImage.Name)
cellView.tableCellImageView.image = imageName
return cellView
} else if tableColumn?.identifier == .lhsCellName {
let cellView = tableView.makeView(withIdentifier: .lhsCellName, owner: self) as! NSTableCellView
cellView.textField?.stringValue = tableDataList[row]
return cellView
} else{
return nil
}
}
Related
I'm trying to programmatically populate the cells of a column with images already defined in an array (flags).
In IB I have an Image View directly within a Table Cell View. In the ViewController this is what I'm doing:
public func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
guard let cellView = tableView.makeView(withIdentifier: tableColumn!.identifier, owner: self) as? NSTableCellView else { return nil }
if tableColumn?.title == "flag" {
cellView.imageView?.image = NSImage(named: flags[row]) // NOT WORKING
} else if tableColumn?.title == "country" {
cellView.textField?.stringValue = flags[row].uppercased()
}
return cellView
}
This results in the text field cells in the "country" column getting set fine, but each of the cells in the "flag" column all have the default image I set in IB--or nothing if I take that out.
According to the tutorials and StackOverflow posts I've looked through, it seems that I'm doing everything right--but obviously I've messed up something.
(In response to the screen cast shared in the comments)
Notice how that Image View (in the cell) is not referenced by anything (its "Referencing Outlets" section on the right is empty).
Your image view is a subview of its cell (as indicated by its position in the view heiarchy on the left side bar), so you could presumably access it using something like:
let imageView = cell.subViews.first(where: { $0 is NSImageView }) as! NSImageView
imageView.image = NSImage(named: flags[row])
...but that's obviously clunky.
Instead, you should select your cell, and drag from its imageView outlet, to the Image View. This will make a new reference, which will make cell.imageView non-nil.
Alternatively, I would suggest you just delete your cell, and create a new one from the "Image & Test Table Cell View" from the "Object Library". It'll have all the outlets hooked up already.
I'm pulling in some JSON data and displaying it in a UITableView (iOS/iPhone 8). It displays the image, title, and description of each value. I've successfully got that down, however, are having trouble pulling the image into a separate View Controller.
By that, I mean, when a cell on the first View Controller is tapped, another view controller opens to display just the information from that cell.
I've been able to make the title and description accessible via a global variable and an indexPath. But the same won't apply to an image, due to a conflict with strings.
I've listed below what I have successfully done with the title and description strings and then show my proposition (which doesn't work of course).
How can I get an image that has already been loaded and is in an array, to be accessible like I already have with the title and description, for use in another View Controller?
The code that formats and gathers values from the JSON:
if let jsonData = myJson as? [String : Any] { // Dictionary
if let myResults = jsonData["articles"] as? [[String : Any]] {
// dump(myResults)
for value in myResults {
if let myTitle = value["title"] as? String {
// print(myTitle)
myNews.displayTitle = myTitle
}
if let myDesc = value["description"] as? String {
myNews.displayDesc = myDesc
}
if let mySrc = value["urlToImage"] as? String {
// print(mySrc)
myNews.src = mySrc
}
self.myTableViewDataSource.append(myNews)
// dump(self.myTableViewDataSource)
// GCD
DispatchQueue.main.async {
self.myTableView.reloadData()
}
}
}
}
Two variables I have outside of the class, in order to use them globally:
var petsIndex = ""
var petsDesc = ""
The code that works with the UITableView and its cells:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let myCell = tableView.dequeueReusableCell(withIdentifier: "reuseCell", for: indexPath)
let myImageView = myCell.viewWithTag(2) as! UIImageView
let myTitleLabel = myCell.viewWithTag(1) as! UILabel
myTitleLabel.text = myTableViewDataSource[indexPath.row].displayTitle
let myURL = myTableViewDataSource[indexPath.row].src
loadImage(url: myURL, to: myImageView)
return myCell
}
The code that I'm using to send the JSON values to another View Controller. I achieve this by utilizing those global variables:
// If a cell is selected, view transitions into a different view controller.
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
petsIndex = self.myTableViewDataSource[indexPath.row].displayTitle
petsDesc = self.myTableViewDataSource[indexPath.row].displayDesc
// Img needs to go here
myIndex = indexPath.row
performSegue(withIdentifier: "segue", sender: self)
}
Here's what I was doing to maybe solve my problem. I converted the string to a UIImage? or a UIImageView? and passed it as data. I left the variable empty and would change it as the data came available. That would occur, when the cell was clicked. Then inside of the second View Controller, I would utilize a an IBOutlet for the UIImageView:
// Variable outside of the class
var petsImg: UIImageView? = nil
petsImg = self.myTableViewDataSource[indexPath.row].src
I'm stumped at this point. I have gotten errors about the image being a string and needed to be converted. And when it was converted, the variable always came back is empty or nil.
Update:
I just tried doing this. It works and doesn't throw any errors. However, I still get a value of nil
petsImg = UIImage(named: self.myTableViewDataSource[indexPath.row].src)
When you perform a segue, you can intercept the call so to prepare the view controller it is showing. The view of this controller at this point has not loaded yet, and so you will need to create properties inside your PostViewController; you could create properties for the title, description, and image.
However, it will be a lot easier passing this information around as your NewsInfo object, for example:
struct NewsInfo {
let displayTitle: String
let displayDesc: String
let src: String
var imageURL: URL { return URL(string: src)! }
}
As well as a custom cell class that takes a NewsInfo object as an argument to populate the outlets.
class NewsInfoTableViewCell: UITableViewCell {
var newsInfo: NewsInfo? {
didSet {
updateOutlets()
}
}
override func prepareForReuse() {
super.prepareForReuse()
newsInfo = nil
}
private func updateOutlets() {
textLabel?.text = newsInfo?.displayTitle
detailTextLabel?.text = newsInfo?.displayDesc
// loadImage()
}
}
Setup the custom table cell class and set the newsInfo property after dequeuing.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuseCell", for: indexPath) as! NewsInfoTableViewCell
cell.newsInfo = myTableViewDataSource[indexPath.row]
return cell
}
When the cell is selected, you can pass it as the sender for performing the segue rather than setting the global variables to populate the PostViewController on viewDidLoad.
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if let cell = tableView.cellForRow(at: indexPath) as? NewsInfoTableViewCell {
performSegue(withIdentifier: "segue", sender: cell)
}
}
You can remove this whole method if you replace your existing segue by ctrl-dragging from the prototype cell to the PostViewControllerin IB to make the cell the sender of the segue.
We want this because we will intercept the segue to prepare the destination view controller by passing it the NewsInfo object of the cell that was selected and triggered the segue.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
switch (segue.destination) {
case (let controller as PostViewController, let cell as NewsInfoTableViewCell):
controller.newsInfo = cell.newsInfo
default:
break
}
}
Similar to how we pass a NewsInfo object to the cell to populate the outlets, you can do the same thing for the PostViewController.
Quick and dirty solution
In your second view controller load the image using:
// With petsImg being the url to your image:
if let url = URL(string: petsImg), let imageData = Data(contentsOf: url) {
imagePost.image = UIImage(data: data)
}
Proper solution
You should not work with global variables to pass data from one view controller to another (read why). Rather look at this question's answer to find out how to transfer data (in your case: the myNews object) from the table view to a detail view:
Send data from TableView to DetailView Swift
If this is too abstract, you can look at this tutorial. It covers what you want to do: https://www.raywenderlich.com/265-uisplitviewcontroller-tutorial-getting-started
It looks like your image is not an image but a url to an image. You can load images into image views using a library like nuke: https://github.com/kean/Nuke
Since network requests are called asynchronously, its a bit difficult to see at which point you're trying to configure your UIImageView. But once you have your network response you will do one of the two:
If your view controller is not yet loaded, (ie you load it once your network response is complete) you can configure the UIImageView in the prepare for sequel method.
If your view controller is already loaded (which is perfectly fine), you will need to set a reference to that view controller in the prepare for segue method. Then you can configure the view controller once the network request is made. I would make the reference to that VC weak, as the system (navigation stack) is already holding on to the VC strongly.
PS: I suggest you de-serialize your JSON response to an object. It will go a long way to help us understand your code. It's hard to see your issue when you're passing dictionary objects around. I suggest you use one of the following:
1. Codable protocol
2. ObjectMapper
3. MapCodableKit (this one is my library which I use personally)
PPS: I assumed you use storyboards.
I have a collectionView of buttons as pictured below. I want to be able to select multiple of these cells, and in doing so pass the title of each selected button into an array of Strings.
UICollectionView - each cell has a button with a title
The UICollectionView is in WordViewController class
class WordViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout
And the UICollectionViewCell is in it's own file.
import UIKit
class WordCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var wordView: UIButton!
#IBAction func buttonTapped(_ sender: UIButton) {
if wordView.isSelected == true {
wordView.isSelected = false
wordView.backgroundColor = UIColor.blue
}else {
wordView.isSelected = true
wordView.backgroundColor = UIColor.green
}
}
}
I'm very new to Swift and I have been trying to find an answer to this for days, but I can't figure it out. I suspect I may have to use indexPathsForSelectedItems but I have tried this and can't get it working.
func indexSelected () {
let collectionView = self.collectionView
let indexPath = collectionView?.indexPathsForSelectedItems?.first
print(indexPath!)
let cell = collectionView?.cellForItem(at: indexPath!) as? WordCollectionViewCell
let data = cell?.wordView.currentTitle
print(data!)
}
I'm not sure if I have something fundamental wrong in the way I have set up my CollectionView or if it is something to do with me using buttons within the CollectionViewCells.
Any help would be very appreciated.
This is one way you could do it. First get the indexPaths for the selected cells. Then loop through the indexPaths and get your cell for each IndexPath (cast them as your custom CollectionViewCell to access your button). Now you can append each title to an array to save them.
var titleArray = [String]()
guard let selectedIndexPaths = collectionView.indexPathsForSelectedItems else { return }
for indexPath in selectedIndexPaths {
if let cell = collectionView.cellForItem(at: indexPath) as? WordCollectionViewCell {
self.titleArray.append(cell.yourButton.titleLabel?.text)
}
}
Welcome to SO. This sounds a bit like an X/Y problem: A case where you are asking about how to implement a specific (often sub-optimal) solution rather than asking about how to solve the problem in the first place.
You should not treat the views in your collection view as saving data. (buttons are views.)
You should use the button to figure out the indexPath of the cell the user tapped and then look up the information in your data model.
You should set up an array of structs (or an array of arrays, if your collection view is in sections of rows.) Each of those structs should contain the current settings for a cell.
Your collectionView(_:cellForItemAt:) method should use the array of structs to configure your sell for display.
As the user taps buttons and selects cells, you should update the struct(s) at the appropriate IndexPath(s) and then tell the collection view to update those cell.
If you need to do something with the selected cells, you should ask the collection view for an array of the selected cells, you should use those IndexPaths to index into your model array and fetch the struct for each IndexPath, and then look up teh data you need.
EDIT:
You can use a really simple extension to UICollectionView to find the indexPath of any view inside your collection view (and a button is a view, as mentioned...)
extension UICollectionView {
func indexPathForCellContaining( view: UIView) -> IndexPath? {
let viewCenter = self.convert(view.center, from: view.superview)
return self.indexPathForItem(at: viewCenter)
}
}
I have a View1 when i click on textbox i am going to view2(table view) to pick a value. I want to send the picked value to view1 for that textbox.
The controls are created programmatically so i am not using segue,IBActions.
I am trying to use the protocol methods still no success. Here is what i have tried.
class DynamicSuperView: UIViewController,UITableViewDelegate,UITableViewDataSource,dropdownDelegate,UITextFieldDelegate
{
func setValue(value:AnyObject)
{
print("dynamic view delegate method executed")
self.labelText = value as! String
//return selectedValue;
}
override func viewDidLoad() {
}
}
The second class is here with delegate method..
protocol dropdownDelegate {
func setValue(value: AnyObject);
}
class testClass: UIViewController,UITableViewDataSource,UITableViewDelegate,UISearchBarDelegate {
var delegate:dropdownDelegate! = nil
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let vcName = names[indexPath.row]
print ("Table view cell clicked and value passed: \(vcName)")
if let cell = tableView.cellForRow(at: indexPath) {
cell.accessoryType = .checkmark
}
self.navigationController?.popViewController(animated: true)
delegate.setValue(value: "Testing delegate")
}
}
Once i select the value in the tableview i am calling the delegate method and trying to pass that value but no success.
I don't want to create the new instance of the previous view controller because i will lose the data already entered by the user, so i am popping the current view controller and going to the previous view controller.
Please suggest if my approach i correct or not?
ERROR:
fatal error: unexpectedly found nil while unwrapping an Optional value
Thank you in advance
Try this:
view func ButtonPressed() {
print("Button Pressed!!") // This will create the new instance of the view controller.
let vc = UIStoryboard(name:"Main", bundle:nil).instantiateViewController(withIdentifier: "Storage") as! testClass
vc.delegate = self
self.navigationController?.pushViewController(vc, animated:true)
}
You are not setting the delegate to first view controller.
I am implementing a commentView for my app. I have a main view which is tableview contains picture and a button to go comment view.
I want that when user tap comment button in table view, view shows comment view and pass PFObject by prepareforSegue method.
now comment button works, but I have an error from prepareforsegue
here is my code.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "mainToComment") {
let destViewController : CommentVC = segue.destinationViewController as! CommentVC
destViewController.parentObjectID = parentObjectID
let selectedRowIndex = self.tableView.indexPathForSelectedRow
destViewController.object = (postsArray[(selectedRowIndex?.row)!] as? PFObject)
and here is my how my button works.
#IBAction func commentButtonTapped(sender: AnyObject) {
let button = sender as! UIButton
let view = button.superview!
let cell = view.superview as! MainTVCE
let indexPath = tableView.indexPathForCell(cell)
parentObjectID = postsArray[(indexPath?.row)!].objectId!!
when I debug, selectedRowIndex has no value(nil)
I think it cause of I tap button instead of cell.
How can I set indexPath for this?
or
How can I make it work?
I don't know name of your main TableViewCell view controller. Assume that, I name this view controller is MainTableViewCell.
I create a closure in MainTableViewCell:
var didRequestToShowComment:((cell:UITableViewCell) -> ())?
When button comment is tapped:
#IBAction func commentButtonTapped(sender: AnyObject) {
self.didRequestToShowComment?(self) // self is this UITableViewCell
}
In table cellForRowAtIndex... of your main view controller.
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
...
mainTableViewCell.didRequestToShowComment = { (cell) in
let indexPath = tableView.indexPathForCell(cell)
let objectToSend = postsArray[indexPath.row] as? PFObject
// Show your Comment view controller here, and set object to send here
}
...
return cell
}