The code below is the only code I am using. I have programmatically built a UISlider with a label that I want to update. I've written a function that should call the sender of the UISlider and update the label field to the value of the slider. But it keeps throwing the "unresolved identifier" error for the variable name of the label. Where do I place the function so it can access the label value? I've tried everything.
import UIKit
class ViewController: UIViewController {
override func viewDidLoad()
{
super.viewDidLoad()
let mySlider = UISlider(frame:CGRect(x: 60, y:550, width: 300, height: 20))
mySlider.minimumValue = 5
mySlider.maximumValue = 60
mySlider.isContinuous = true
mySlider.tintColor = .white
mySlider.addTarget(self, action: #selector(ViewController.sliderValueDidChange(_:)), for: .valueChanged)
let minuteLabel = UILabel(frame: CGRect(1500, 2000, 150, 1200))
minuteLabel.center = CGPoint(200, 350)
minuteLabel.textAlignment = .center
minuteLabel.font = UIFont(name: minuteLabel.font.fontName, size:250)
mySlider.addTarget(self, action: #selector(ViewController.sliderValueDidChange(_:)),for: .valueChanged)
minuteLabel.textColor = UIColor.white
minuteLabel.text = "\(mySlider.value)"
self.view.addSubview(minuteLabel)
self.view.addSubview(mySlider)
}
public func sliderValueDidChange(_sender: UISlider) {
minuteLabel.text = "\(_sender.value)"
}
}
It's because you create minuteLabel in viewDidLoad() but not assigning to any property inside your ViewController.
You can just create property minuteLabel inside class and assign your minuteLabel from viewDidLoad() to this.
class ViewController: UIViewController {
private var minuteLabel: UILabel?
override func viewDidLoad()
{
super.viewDidLoad()
let mySlider = UISlider(frame:CGRect(x: 60, y:550, width: 300, height: 20))
mySlider.minimumValue = 5
mySlider.maximumValue = 60
mySlider.isContinuous = true
mySlider.tintColor = .white
mySlider.addTarget(self, action: #selector(ViewController.sliderValueDidChange(_:)), for: .valueChanged)
let minuteLabel = UILabel(frame: CGRect(1500, 2000, 150, 1200))
minuteLabel.center = CGPoint(200, 350)
minuteLabel.textAlignment = .center
minuteLabel.font = UIFont(name: minuteLabel.font.fontName, size:250)
mySlider.addTarget(self, action: #selector(ViewController.sliderValueDidChange(_:)),for: .valueChanged)
minuteLabel.textColor = UIColor.white
minuteLabel.text = "\(mySlider.value)"
self.view.addSubview(minuteLabel)
self.view.addSubview(mySlider)
self.minuteLabel = minuteLabel // assign to class property
}
public func sliderValueDidChange(_sender: UISlider) {
minuteLabel?.text = "\(_sender.value)"
}
}
Related
I want my swift code to use a if statement or another sequence to only display a border on one of the buttons if click at a time. So a border can only be seen on one button at a time that button would be the last one pressed. I know I could say layer.border with 0 on each button that should be selected but I want to see if there is a more efficient way to do this.
import UIKit
class ViewController: UIViewController {
var ba = UIButton()
var bb = UIButton()
var bc = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
[ba,bb,bc].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
view.addSubview($0)
}
ba.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
bb.frame = CGRect(x: 100, y: 0, width: 100, height: 100)
bc.frame = CGRect(x: 200, y: 0, width: 100, height: 100)
ba.backgroundColor = .blue
bb.backgroundColor = .orange
bc.backgroundColor = .darkGray
ba.addTarget(self, action: #selector(pressa), for: .touchDown)
bb.addTarget(self, action: #selector(pressb), for: .touchDown)
bc.addTarget(self, action: #selector(pressc), for: .touchDown)
}
#objc func pressa(){
ba.layer.borderWidth = 2
}
#objc func pressb(){
bb.layer.borderWidth = 2
}
#objc func pressc(){
bc.layer.borderWidth = 2
}
}
you can add target to all buttons at the forEach and be only one method as #Sh_Khan mention
import UIKit
class ViewController: UIViewController {
var ba = UIButton()
var bb = UIButton()
var bc = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
[ba,bb,bc].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
view.addSubview($0)
$0.addTarget(self, action: #selector(pressAll(_:)), for: .touchDown)
}
ba.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
bb.frame = CGRect(x: 100, y: 0, width: 100, height: 100)
bc.frame = CGRect(x: 200, y: 0, width: 100, height: 100)
ba.backgroundColor = .blue
bb.backgroundColor = .orange
bc.backgroundColor = .darkGray
}
#objc func pressAll(_ sender:UIButton) {
[ba,bb,bc].forEach { $0.layer.borderWidth = 0 } // reset all
sender.layer.borderWidth = 2
}
}
See how you have used an array in [ba,bb,bc].forEach { ... } to reduce code duplication? Using arrays is the key. Rather than putting the three buttons in an array inline like that, create a property instead:
var buttons: [UIButton]!
override func viewDidLoad() {
super.viewDidLoad()
buttons = [ba,bb,bc]
buttons.forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
view.addSubview($0)
$0.addTarget(self, action: #selector(buttonPressed), for: .touchDown)
}
...
}
I have used the same selector buttonPressed for all three buttons. buttonPressed can accept a parameter of type UIButton, that tells us which button is pressed:
#objc func buttonPressed(_ sender: UIButton) {
buttons.forEach { ba.layer.borderWidth = 0 } // deselect all buttons first...
sender.layer.borderWidth = 2 // select the tapped button
}
If you have more than 3 buttons to manage, I suggest you don't use UIButtons at all. You should use a UICollectionView. (Learn how to use them) This view will handle the selection for you. It also allows scrolling when there's not enough space to show all the buttons. You just need to create a custom UICollectionViewCell and override its isSelected property:
override var isSelected: Bool {
didSet {
if isSelected {
self.layer.borderWidth = 2
} else {
self.layer.borderWidth = 0
}
}
}
It could be 1 method like this
[ba,bb,bc].forEach { $0.addTarget(self, action: #selector(pressAll(_:)), for: .touchDown) }
}
#objc func pressAll(_ sender:UIButton) {
[ba,bb,bc].forEach { $0.layer.borderWidth = 0 } // reset all
sender.layer.borderWidth = 2
}
I create UITextView with a random tag and text, but it is created with one variable, is it possible to update the variable after creation UITextView (by clicking the add button)? Maybe add a random number to it, for example newText1, newText2.. etc.
So that the next UITextView is already created with a new variable?
P.S Sorry, if the question is silly, I just recently started to study Swift
#IBOutlet weak var addTextButton: UIButton!
#IBOutlet weak var StoriesView: UIView!
var newText = UITextView()
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func addTextButton(_ sender: Any) {
let maxNumber = 10000
let i = Int(arc4random_uniform(UInt32(maxNumber)))
newText = UITextView(frame: CGRect(x: self.StoriesView.frame.origin.x + 40, y: self.StoriesView.frame.origin.y + 40, width: 380, height: 80))
self.StoriesView.addSubview(newText)
newText.font = UIFont(name: "Verdana", size: 11)
newText.text = "TAP TO EDIT #\(i)"
newText.sizeToFit()
newText.textColor = UIColor.black
newText.backgroundColor = UIColor.clear
newText.tag = i
newText.isEditable = true
newText.isSelectable = true
newText.isUserInteractionEnabled = true
newText.allowsEditingTextAttributes = true
newText.translatesAutoresizingMaskIntoConstraints = true
newText.enablesReturnKeyAutomatically = true
newText.delegate = self
}
UPD:
let fontToolbar = UIToolbar(frame:CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 50))
fontToolbar.barStyle = .default
fontToolbar.items = [
UIBarButtonItem(title: "Green", style: .plain, target: self, action: #selector(greenColor)),
UIBarButtonItem(title: "Blue", style: .plain, target: self, action: #selector(blueColor)),
UIBarButtonItem(title: "Red", style: .plain, target: self, action: #selector(redColor)),
UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil),
UIBarButtonItem(title: "Close Keyboard", style: .plain, target: self, action: #selector(dismissKeyboard))]
fontToolbar.sizeToFit()
newText.inputAccessoryView = fontToolbar
in the toolBar above the keyboard I have buttons, here we change the color
#objc func redColor() {
newText.textColor = UIColor.red}
#objc func blueColor() {
newText.textColor = UIColor.blue}
#objc func greenColor() {
newText.textColor = UIColor.green}
So the color changes only in the newly created UITextView
On click of button, create a new texView and assign it a tag value. Once it is added, update the value of i to +1, so that every textView added has a new tag value.
var i = 1
var newText = UITextView()
#IBAction func addTextButton(_ sender: Any) {
newText = UITextView(frame: CGRect(x: self.StoriesView.frame.origin.x + 40, y: self.StoriesView.frame.origin.y + 40, width: 380, height: 80))
self.StoriesView.addSubview(newText)
newText.font = UIFont(name: "Verdana", size: 11)
newText.text = "TAP TO EDIT #\(i)"
newText.sizeToFit()
newText.textColor = UIColor.black
newText.backgroundColor = UIColor.clear
newText.tag = i
newText.isEditable = true
newText.isSelectable = true
newText.isUserInteractionEnabled = true
newText.allowsEditingTextAttributes = true
newText.translatesAutoresizingMaskIntoConstraints = true
newText.enablesReturnKeyAutomatically = true
newText.delegate = self
//increment i
i+=1
}
then you can access your textField via tag values like this:
if let textView = self.StoriesView.viewWithTag(i) as? UITextView {
// textView.text = "change it"
}
UPDATE:
Add textView Delegate method, and once a textView starts editing, change the newText value to the currently editing textView
class ViewController : UIViewController, UITextViewDelegate {
func textViewDidBeginEditing(_ textView: UITextView) {
newText = textView
}
}
I have modified your code a bit to have new UITextView object with button click
import UIKit
class ScannerViewController: UIViewController, UITextViewDelegate {
#IBOutlet weak var StoriesView: UIView!
#IBOutlet weak var addTextButton: UIButton!
var yposition: CGFloat!
var textFieldTag: [Int]! = []
override func viewDidLoad() {
super.viewDidLoad()
yposition = 20
}
#IBAction func addTextButton(_ sender: Any) {
let xposition = self.StoriesView.frame.origin.x
let maxNumber = 10000
let i = Int(arc4random_uniform(UInt32(maxNumber)))
textFieldTag.append(i)
let newText = UITextView(frame: CGRect(x: xposition , y: yposition , width: 380, height: 40))
self.StoriesView.addSubview(newText)
newText.font = UIFont(name: "Verdana", size: 11)
newText.text = "TAP TO EDIT #\(i)"
newText.sizeToFit()
newText.textColor = UIColor.black
newText.backgroundColor = UIColor.yellow
newText.tag = i
newText.isEditable = true
newText.isSelectable = true
newText.isUserInteractionEnabled = true
newText.allowsEditingTextAttributes = true
newText.translatesAutoresizingMaskIntoConstraints = true
newText.enablesReturnKeyAutomatically = true
newText.delegate = self
yposition = yposition + 45
}
#IBAction func accessTextFields(_ sender: Any) {
//access all text fields
for tag in textFieldTag {
if let textField = self.StoriesView.viewWithTag(tag) as? UITextView {
//change properties here
textField.backgroundColor = .cyan
}
}
//access specific text fields
if let textField = self.StoriesView.viewWithTag(textFieldTag.first!) as? UITextView {
//change properties here
textField.backgroundColor = .orange
}
if let textField = self.StoriesView.viewWithTag(textFieldTag[textFieldTag.count - 1]) as? UITextView {
//change properties here
textField.backgroundColor = .green
}
}
}
It will have an output as this!!
I would like to use a simple function to update the text inside a UIlabel. I'm getting the error
Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
I've looked into this problem and found this excellent post that suggested using optional binding/guard statements.
import UIKit
class ViewController: UIViewController {
var mainImageView: UIImageView!
var chooseButton: UIButton!
var nameLabel: UILabel!
override func loadView() {
view = UIView()
view.backgroundColor = .white
let btn = UIButton(type: .custom) as UIButton
btn.backgroundColor = .blue
btn.layer.borderColor = UIColor.darkGray.cgColor
btn.layer.borderWidth = 2
btn.setTitle("Pick a side", for: .normal)
btn.frame = CGRect(x: 100, y: 100, width: 200, height: 100)
btn.addTarget(self, action: #selector(clickMe), for: .touchUpInside)
btn.layer.cornerRadius = btn.frame.size.height/2
self.view.addSubview(btn)
let nameLabel = UILabel()
nameLabel.text = "Here is your side"
nameLabel.textAlignment = .center
nameLabel.backgroundColor = .cyan
nameLabel.frame = CGRect(x: 100, y: 400, width: 200, height: 100)
self.view.addSubview(nameLabel)
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#objc func clickMe(sender:UIButton!) {
print("Button Clicked")
self.nameLabel.text = "updated title"
}
}
The problem seems to be that you are adding the label manually in loadView but you are creating a local label object that you add to the view and not your class property so the class property nameLabel is always nil
Change
let nameLabel = UILabel()
to
self.nameLabel = UILabel()
I have 8 buttons and I want to display a picture every time I press the buttons.
What I wonder is, do I need to have 8 functions to display these images?
Or is there any easier ways?
Here is how I've done it, it works as it should, but I do not want to repeat the same things over and over again?
var imageView1:UIImageView!
var imageView2:UIImageView!
var imageView3:UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
showImage1()
showImage2()
showImage3()
tapGestureRecognizerFunc()
}
#objc func button1Tap() {
if self.imageView1.isHidden {
self.imageView1.isHidden = false
}else{
self.imageView1.isHidden = true
}
}
#objc func button2Tap() {
if self.imageView2.isHidden {
self.imageView2.isHidden = false
}else{
self.imageView2.isHidden = true
}
}
#objc func button3Tap() {
if self.imageView3.isHidden {
self.imageView3.isHidden = false
}else{
self.imageView3.isHidden = true
}
}
func showImage1() {
imageView1 = UIImageView(frame: CGRect(x: 271, y: 8, width: 29, height: 29))
imageView1.image = UIImage(named: "Done.png")
imageView1.contentMode = .scaleAspectFit
View1.addSubview(imageView1)
imageView1.isHidden = true
}
func showImage2() {
imageView2 = UIImageView(frame: CGRect(x: 271, y: 8, width: 29, height: 29))
imageView2.image = UIImage(named: "Done.png")
imageView2.contentMode = .scaleAspectFit
View2.addSubview(imageView2)
imageView2.isHidden = true
}
func showImage3() {
imageView2 = UIImageView(frame: CGRect(x: 271, y: 8, width: 29, height: 29))
imageView2.image = UIImage(named: "Done.png")
imageView2.contentMode = .scaleAspectFit
View3.addSubview(imageView2)
imageView2.isHidden = true
}
func tapGestureRecognizerFunc () {
let exercise1Tap = UITapGestureRecognizer(target: self, action: #selector(button1Tap))
exercise1Tap.numberOfTapsRequired = 2
View1.addGestureRecognizer(exercise1Tap)
let exercise2Tap = UITapGestureRecognizer(target: self, action: #selector(button2Tap))
exercise2Tap.numberOfTapsRequired = 2
View2.addGestureRecognizer(exercise2Tap)
let exercise3Tap = UITapGestureRecognizer(target: self, action: #selector(button3Tap))
exercise3Tap.numberOfTapsRequired = 2
View3.addGestureRecognizer(exercise3Tap)
}
yes i'm newbie
Since I don't know, where and how you create the Buttons it is difficult to answer.
The following is just a tip.
You should use an array of UIImageView
Your callback should use the Form buttonAction(sender : UIButton)
You could use a tag for the button to get the number of the corresponding button
For example:
class ViewController: UIViewController {
var imageviews : [UIImageView] = []
override func viewDidLoad() {
super.viewDidLoad()
for i in 1...8 {
let imageview = UIImageView()
view.addSubview(imageview)
imageview.tag = i
imageviews.append(imageview)
let button = UIButton(frame: CGRect(x: 0, y: CGFloat(i)*50.0, width: 100, height: 30))
view.addSubview(button)
button.setTitle("Button \(i)", for: .normal)
button.setTitleColor(.black, for: .normal)
button.tag = i
button.addTarget(self, action: #selector(buttonAction), for: .touchUpInside)
}
}
#objc func buttonAction(sender : UIButton) {
let index = sender.tag
print("Button \(index) pressed")
imageviews[index].isHidden = !imageviews[index].isHidden
}
}
When I do this in AppDelegate:
window?.rootViewController = {
let mainController = MenuViewController()
return mainController
}()
I get this:
But when I do this in AppDelegate:
window?.rootViewController = {
let mainController = UINavigationController(rootViewController: MenuViewController())
return mainController
}()
I get this:
Why and how do I fix? Please specify which information if more information is needed.
Here is the MenuView code that lays out the buttons manually and also sets up the properties of the buttons:
class MenuView: UIView {
//title
let titleLabel: UILabel = {
let label = UILabel()
label.text = "Survive The Attackers!!"
label.backgroundColor = UIColor.white
return label
}()
//set up buttons
let newGameButton: UIButton = {
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("New Game", for: .normal)
button.setTitleColor(UIColor.black, for: .normal)
button.backgroundColor = UIColor.white
button.layer.borderWidth = 2.0;
button.layer.borderColor = UIColor.black.cgColor
return button
}()
let resumeButton: UIButton = {
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("Resume Game", for: .normal)
button.setTitleColor(UIColor.black, for: .normal)
button.backgroundColor = UIColor.white
button.layer.borderWidth = 2.0;
button.layer.borderColor = UIColor.black.cgColor
return button
}()
let highScoresButton: UIButton = {
let button = UIButton()
button.translatesAutoresizingMaskIntoConstraints = false
button.setTitle("High Scores", for: .normal)
button.setTitleColor(UIColor.black, for: .normal)
button.backgroundColor = UIColor.white
button.layer.borderWidth = 2.0;
button.layer.borderColor = UIColor.black.cgColor
return button
}()
//add subviews and initialize the view
override init(frame: CGRect){
super.init(frame: frame)
self.backgroundColor = UIColor(patternImage: UIImage(named: "background1.png")!)
addSubview(titleLabel)
addSubview(newGameButton)
addSubview(resumeButton)
addSubview(highScoresButton)
}
required init?(coder aDecoder: NSCoder) {
fatalError("It's Apple. What did you expect?")
}
//manually layout the main menu
override func layoutSubviews() {
var cursor: CGPoint = .zero
let buttonHeight = CGFloat(40.0);
let buttonWidth = CGFloat(160.0);
let labelWidth = buttonWidth + 20;
let spacing = bounds.height/4
let titleY = 2/3 * spacing
cursor.y = titleY
cursor.x = bounds.width/2 - labelWidth/2
titleLabel.frame = CGRect(x: cursor.x, y: cursor.y, width: labelWidth, height: buttonHeight)
cursor.y = spacing
cursor.x = bounds.width/2 - buttonWidth/2
newGameButton.frame = CGRect(x: cursor.x, y: cursor.y, width: buttonWidth, height: buttonHeight)
cursor.y += spacing
resumeButton.frame = CGRect(x: cursor.x, y: cursor.y, width: buttonWidth, height: buttonHeight)
cursor.y += spacing
highScoresButton.frame = CGRect(x: cursor.x, y: cursor.y, width: buttonWidth, height: buttonHeight)
}
The buttons are laid out manually in layoutSubviews
Here is my MenuView controller code:
class MenuViewController: UIViewController {
var delegateID: String = UUIDVendor.vendUUID()
private var menuView: MenuView {
return view as! MenuView
}
init(){
super.init(nibName: nil, bundle: nil)
//edgesForExtendedLayout = .init(rawValue: 0)
}
required init?(coder aDecoder: NSCoder){
fatalError()
}
//loads the view in and sizes it correctly
override func loadView() {
view = MenuView()
//extendedLayoutIncludesOpaqueBars = false
}
override func viewDidLoad() {
menuView.newGameButton.addTarget(self, action: #selector(MenuViewController.newGameButtonTapped(button:)), for: .touchUpInside)
menuView.resumeButton.addTarget(self, action: #selector(MenuViewController.resumeGameButtonTapped(button:)), for: .touchUpInside)
menuView.highScoresButton.addTarget(self, action: #selector(MenuViewController.highScoreButtonTapped(button:)), for: .touchUpInside)
menuView.setNeedsLayout()
}
//fuction that handles the event when the newGameButton is tapped
#objc func newGameButtonTapped(button: UIButton){
//reset the data in the model somehow
navigationController?.pushViewController(GameViewController(), animated: true)
}
//function that handles the event when the resume game button is tapped
#objc func resumeGameButtonTapped(button: UIButton){
}
//function that handels the event when the high scores button is tapped
#objc func highScoreButtonTapped(button: UIButton){
}
call super for layoutSubviews
private var menuView: MenuView = {
let vw = MenuView()
return vw
}()
override func viewDidLoad() {
super.viewDidLoad()
view = MenuView() //Add here
//Your code
}
And remove loadView() from MenuViewController