guys.
I'm asking for help. It seems a very easy task, but I can solve it for the whole day.
I'm trying to create a side menu using container view. When a user presses More button(barButtonItem), the whole view slide to the right and menu table appears. I know how to make it using Notifications. But I would like to solve it through delegation. Here is my storyboard.
enter image description here
and code:
import UIKit
class RootViewController: UIViewController, SideMenuDelegate {
#IBOutlet weak var leading: NSLayoutConstraint!
var sideMenuIsOpen = false
var sideMenu: MainViewController?
override func viewDidLoad() {
super.viewDidLoad()
sideMenu?.delegate = self
}
func openSideMenu() {
toggleSideMenu()
}
func toggleSideMenu() {
if sideMenuIsOpen {
leading.constant = 0
} else {
leading.constant = 240
}
}
}
and:
import UIKit
protocol SideMenuDelegate {
func openSideMenu()
}
class MainViewController: UIViewController {
var delegate: SideMenuDelegate?
#IBAction func toggleSideMenu(_ sender: UIBarButtonItem) {
if let delegateUnwrapped = delegate {
delegateUnwrapped.openSideMenu()
} else {
print("nil")
}
}
override func viewDidLoad() {
super.viewDidLoad()
BackgroundImageView.createBackground(insideView: self, image: .mainViewBackground)
}
}
Thank you!
This
var sideMenu: MainViewController? // is nil
override func viewDidLoad() {
super.viewDidLoad()
sideMenu?.delegate = self
}
has no reference to the current displayed main , it's nil when you present the main from the Root give it the reference
Related
This question already has answers here:
Passing data between view controllers
(45 answers)
Closed 2 years ago.
I am working on a Magic the Gathering Counter app. For my app, I want to click twentyLife(), thirtyLife(), or fourtyLife() to change the value of a variable in another view controller (i.e. FifthViewController.)
Second view controller code:
import UIKit
class SecondViewController: UIViewController {
var vcFive = FifthViewController()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func twentyLife() {
vcFive.lifePoints.text = String(20)
}
#IBAction func thirtyLife() {
vcFive.lifePoints.text = String(20)
}
#IBAction func fortyLife() {
vcFive.lifePoints.text = String(20)
}
I try and call out the fifthViewController as a variable to change my life points text but it does not work.
Here is my code for the fifthViewController:
import UIKit
class FifthViewController: UIViewController {
#IBOutlet weak var lifePoints: UILabel!
var counter = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func lifeUp() {
counter += 1
lifePoints.text = String(counter)
}
#IBAction func lifeDown() {
counter -= 1
lifePoints.text = String(counter)
}
Any help would be appreciated. This is my first app I have been trying to work on from scratch
You should create an instance of your FifthViewController on your SecondViewController, and a variable on your FifthViewController in which you can save the data passed. Like this:
SecondViewController
import UIKit
class SecondViewController: UIViewController {
let fifthVC = self.storyboard?.instantiateViewController(withIdentifier: "fifthVC") as? FifthViewController
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func twentyLife() {
fifthVC.lifePointsInt = 20
}
#IBAction func thirtyLife() {
fifthVC.lifePointsInt = 30
}
#IBAction func fortyLife() {
fifthVC.lifePointsInt = 50
}
}
FifthViewController
import UIKit
class FifthViewController: UIViewController {
var lifePointsInt = Int()
#IBOutlet weak var lifePoints: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
lifePoints.text = "\(lifePointsInt)"
}
#IBAction func lifeUp() {
lifePoints.text = "\(lifePointsInt + 1)"
}
#IBAction func lifeDown() {
lifePoints.text = "\(lifePointsInt - 1)"
}
}
Remember to type in your Storyboard ID in your storyboard for your FifthViewController as "fifthVC" If your pass to your FifthViewController after selecting your Life Count in your SecondViewController you could add self.navigationController?.pushViewController(fifthVC!, animated: true) at the end of each function.
I am a beginner in Swift, and I do not yet understand all the elements.
I am trying to execute a function present in a ViewController (ProjectTabBarController) from another ViewController (ProjectInfosViewController). I end up with an error when I execute the function from the second.
For the context, it is for a navigation button of 3 UIViewController belonging to a UITabBarViewController, itself embedded in a UINavigationController
Thank you in advance ! (Sorry for my bad English)
import UIKit
//MARK:-TAB CONTROLLER
class ProjectTabBarController: UITabBarController {
#IBOutlet weak var ui_saveButton: UIBarButtonItem!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func saveAction(_ sender: Any) {
// code
disableSaveButton() // ALL IT'S FINE HERE
}
func enableSaveButton() {
ui_saveButton.title = "Save"
ui_saveButton.isEnabled = true
}
func disableSaveButton() {
ui_saveButton.title = "Saved"
ui_saveButton.isEnabled = false
} }
//MARK:-PROJECT INFORMATIONS
class ProjectInfosViewController: UIViewController, UITextFieldDelegate {
let superController = ProjectTabBarController()
override func viewDidLoad() {
super.viewDidLoad()
}
func textFieldDidChangeSelection(_ textField: UITextField) {
superController.enableSaveButton() // BUT HERE, DOESN'T
} }
//MARK:-PROJECT FIXTURES
class ProjectFixturesViewController: UIViewController, UITableViewDataSource {
}
//MARK:-PROJECT CONTACT
class ProjectContactViewController: UIViewController {
}
This
let superController = ProjectTabBarController()
is a new vc that's not presented , if the vc is inside the tabController then do
let res = self.tabBarController as! ProjectTabBarController
res.......// call what you need
I'm doing a test of a custom keyboard. This is what I need:
It has to have two UITextFields. Cannot be labels.
The keyboard is an embedded UIView.
The default keyboard should be disabled.
It cannot be a keyboard extension.
Not sure why the app is crashing. PS: Not all the keys are on the code yet. Here is an image of what I'm trying to do and the two View Controllers.
Edit: The error is: Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
First ViewController:
import UIKit
class HomeVC: UIViewController, ButtonTapDelegate {
#IBOutlet var textField1: UITextField!
#IBOutlet var textField2: UITextField!
#IBOutlet var keyboardView: UIView!
var buttonPressed = [String]()
override func viewDidLoad() {
addKeyboard(view: keyboardView)
buttonPressed = [String]()
textField1.inputView = UIView()
textField2.inputView = UIView()
}
func addKeyboard(view: UIView) {
let keyboard = KeyboardVC(nibName: "KeyboardVC", bundle: nil)
view.addSubview(keyboard.view)
addChild(keyboard)
}
func didTapButton(sender: UIButton) {
if sender.tag == 5 {
textField1.text?.append(contentsOf: " ")
} else if sender.tag == 6 {
textField1.text?.removeAll()
buttonPressed = [String]()
} else {
let val = sender.titleLabel?.text
textField1.text?.append(contentsOf: val!)
}
self.textField1.text = buttonPressed.joined(separator: "")
}
}
Here is the second View Controller:
import UIKit
protocol ButtonTapDelegate {
func didTapButton(sender: UIButton)
}
class KeyboardVC: UIViewController {
var delegate: ButtonTapDelegate!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func buttons(_ sender: UIButton) {
delegate.didTapButton(sender: sender)
print(sender)
}
}
var delegate: ButtonTapDelegate!
An implicitly unwrapped optional is essentially a promise that you're definitely going to give the variable a value before you try to access it. The problem in this case is that you haven't done that. Most likely, you want to do this in your first view controller:
func addKeyboard(view: UIView) {
let keyboard = KeyboardVC(nibName: "KeyboardVC", bundle: nil)
keyboard.delegate = self // Now "delegate" will have a value before the function gets called
view.addSubview(keyboard.view)
addChild(keyboard)
}
This is the error Xcode outputs
Unexpectedly found nil while unwrapping an Optional value
I have a viewcontroller that has a tableview and a few buttons; the buttons allow me to insert or remove data. It seems that when I click on Add (which brings up a new viewcontroller via segue as a sheet) the app crashes with the error above. Clicking on remove doesn't have this affect. So it has to do with something regarding the new viewcontroller as a guess. The console doesn't go further into the error other than printing out (lldb)
Here's my code
override func viewDidLoad() {
super.viewDidLoad()
alarmTableView.dataSource = self //error occurs here
alarmTableView.delegate = self //if i remove the above line if will occur here too.
}
My Viewcontroller which the above viewDidLoad func is embedded lists the protocols I need
class ViewController: NSViewController, NSTableViewDelegate, NSTableViewDataSource {
#IBOutlet weak var addAlarm: NSButton!
#IBOutlet weak var resetDataButton: NSButton!
#IBOutlet var alarmArrayController: NSArrayController!
#IBOutlet weak var alarmTableView: NSTableView!
#IBOutlet weak var deleteAll: NSButton!
#objc let moc: NSManagedObjectContext
required init?(coder: NSCoder) {
self.moc = CoreDataHandler.getContext()
super.init(coder: coder)
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
let destinationController = segue.destinationController as! AddAlarmViewController
//pass data to next controller here
}
#IBAction func deleteAllAction(_ sender: Any) {
if (alarmTableView.selectedRow >= 0) {
if (CoreDataHandler.deleteAllObjectsInEntity(entityName: "Alarm")) {
//remove from nsarray controller
for object in alarmArrayController.arrangedObjects as! [Alarm] {
print(object)
alarmArrayController.removeObject(object)
}
alarmTableView.reloadData()
}
}
else {
printInfo(str: "There are no alarms to delete")
}
}
/* Response to the remove alarm button - It removes a selected alarm object from the table */
#IBAction func resetDataAction(_ sender: Any) {
if (alarmTableView.selectedRow >= 0) {
let selectedAlarm = self.alarmArrayController.selectedObjects.first as! Alarm
alarmArrayController.remove(atArrangedObjectIndex: alarmTableView.selectedRow)
CoreDataHandler.deleteObjectInEntity(entityName: "Alarm", obj: selectedAlarm)
alarmTableView.reloadData()
}
else {
//will need a warning or play a sound.
printInfo(str: "Please select an alarm")
}
}
override func viewDidLoad() {
super.viewDidLoad()
printInfo(str: "viewdidload")
print(alarmTableView)
if (alarmTableView != nil) {
printInfo(str: "AlarmTableView Is initialised")
alarmTableView.dataSource = self
alarmTableView.delegate = self
}
else {
printInfo(str: "AlarmTableView is not initialised")
}
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
func printInfo(str: String) {
print("ViewController: \(str)")
}
func tableView(_ tableView: NSTableView, heightOfRow row: Int) -> CGFloat {
return 100.0
}
}
class AddAlarmViewController: ViewController {
#IBOutlet weak var closeButton: NSButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
printClassInfo(str: "viewDidLoad")
CoreDataHandler.saveTestData()
}
#IBAction func closeButtonAction(_ sender: Any) {
self.dismissViewController(self)
}
func printClassInfo(str: String) {
print("AddAlarmViewController \(str)")
}
}
If I remove the lines where the error occurs the app run fine. But I want to override the delegate and datasource and use the functions to further customise the table. I'm also using Cocoa Bindings.
Why am I getting this error?
Update
I haven't solved it yet, but i placed a couple of print statements in my viewDidLoad function. It seems that when the app is first loaded, the table view is initialised. But after when I clicked on the Add button, the table view is then set to nil for some odd reason, as if another table view has been initialised. However the data is still visible
Problem:
class AddAlarmViewController: ViewController {
//...
override func viewDidLoad() {
super.viewDidLoad()
//...
}
}
Your AddAlarmViewController is a subclass of ViewController instead of NSViewController.
In AddAlarmViewController's viewDidLoad you call super.viewDidLoad() which basically calls ViewController's viewDidLoad.
But... in this case ViewController is a new instance as the super class of AddAlarmViewController and none of it's properties are initialized.
Whatever it be, it's probably not what you want.
Solution:
class AddAlarmViewController: NSViewController {
//... rest as it is
}
I'm working on an app, and need to pass data between view and containerView. I need to send data and receive data from both Views.
Let me explain better:
I can change the Label Master (Touch the Container Button) by protocol, but I can not change the Label Container (Touch the Master button). What happens is the Master connects with the container by a following. But do not have a follow Container linking to the Master.
I tried to add but segue to, but it worked.
The Master View Controller:
import UIKit
protocol MasterToContainer {
func changeLabel(text:String)
}
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
var masterToContainer:MasterToContainer?
#IBOutlet var labelMaster: UILabel!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
let view = segue.destinationViewController as? Container
view!.containerToMaster = self
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func button_Container(sender: AnyObject) {
masterToContainer?.changeLabel("Nice! It's work!")
}
func changeLabel(text: String) {
labelMaster.text = text
}
}
The Container View Controller:
import UIKit
protocol ContainerToMaster {
func changeLabel(text:String)
}
class Container: UIViewController, MasterToContainer {
var containerToMaster:ContainerToMaster?
#IBOutlet var labelContainer: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func button_Master(sender: AnyObject) {
containerToMaster?.changeLabel("Amazing! It's work!")
}
func changeLabel(text: String) {
labelContainer.text = text
}
}
Can someone help me?
All you need to do is keep a reference to Container in your master view controller.
That is, you should add an instance variable to Master that will hold a reference to the view controller, not just the view. You'll need to set it in prepareForSegue.
So the beginning of Master View Controller would look something like this:
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
var containerViewController: Container?
#IBOutlet var labelMaster: UILabel!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
containerViewController = segue.destinationViewController as? Container
containerViewController!.containerToMaster = self
}
}
And then in your button function, simply change the label using the variable you just added.
Example:
#IBAction func button_Container(sender: AnyObject) {
containerViewController?.changeLabel("Nice! It's work!")
}
This means you can get rid of your MasterToContainer protocol too.
I tested this code, so I know it works, but unfortunately I am an Objective-C dev, and know nothing about best practices in Swift. So I don't know if this is the best way to go about it, but it certainly works.
Edit:
Here's the exact code I've tested:
Master.swift:
import UIKit
class Master: UIViewController, ContainerToMaster {
#IBOutlet var containerView: UIView!
#IBOutlet var labelMaster: UILabel!
var containerViewController: Container?
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "containerViewSegue" {
containerViewController = segue.destinationViewController as? Container
containerViewController!.containerToMaster = self
}
}
#IBAction func button_Container(sender: AnyObject) {
containerViewController?.changeLabel("Nice! It's work!")
}
func changeLabel(text: String) {
labelMaster.text = text
}
}
Container.swift:
import UIKit
protocol ContainerToMaster {
func changeLabel(text:String)
}
class Container: UIViewController {
#IBOutlet var labelContainer: UILabel!
var containerToMaster:ContainerToMaster?
#IBAction func button_Master(sender: AnyObject) {
containerToMaster?.changeLabel("Amazing! It's work!")
}
func changeLabel(text: String) {
labelContainer.text = text
}
}
I solved it with this code
To send data from ViewController -> ContainerViewController
Class ViewController : UIViewController {
func sendData(MyStringToSend : String) {
let CVC = childViewControllers.last as! ContainerViewController
CVC.ChangeLabel( MyStringToSend)
}
}
in your ContainerViewController
Class ContainerViewController : UIViewController {
#IBOutlet weak var myLabel: UILabel!
func ChangeLabel(labelToChange : String){
myLabel.text = labelToChange
}
}
To send data from ContainerViewController -> ViewController
Class ContainerViewController : UIViewController {
func sendDataToVc(myString : String) {
let Vc = parentViewController as! ViewController
Vc.dataFromContainer(myString)
}
}
and in ViewController
Class ViewController : UIViewController {
func dataFromContainer(containerData : String){
print(containerData)
}
}
I hope this will help someone.
you can use this extension to access the container child
extension UIViewController {
func getContainerChild<vc:UIViewController>(_ viewController : vc,_ hasNavigation : Bool = true) -> (vc) {
guard let vc = self.children[0] as? UINavigationController else {return viewController}
if hasNavigation {
guard let childVC = vc.children[0] as? PurchasedHistoryListVC else {
return viewController}
return childVC as! vc
} else {
return vc as! vc
}
}
}
so you can do some thing like this in your view Controller
let vc = self.getContainerChild(yourChildViewControllerClass())
vc.functionName()