I'm new to swift programming, so this may be a dumb question, but how can I change the content of an UITextView Object by pressing a button.
The example I tested looks like this:
#IBOutlet weak var dataButton: UIButton!
#IBOutlet weak var dataView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func testButtonPressed(sender: UIButton) {
dataView.text = "Test worked."
}
Actually it doesn't work. My Storyboard has a ViewController from the Class where the above code is written. I also have the Button and the TextLabel. Do I need to specify anything in the Interface Builder or is something wrong with my code?
Thanks in advance for any help!!!
Make sure that your IBOutlet's and IBActions are connected in storyboard. It should work. You could set a breakpoint at the line with: dataView.text = "Test worked." to see if the code is reached. If it doesn't reach the breakpoint then your IBAction is not connected properly.
IBAction's sender parameter need an underscore before it, that is:
#IBAction func testButtonPressed(_ sender: UIButton) {
dataView.text = "Test worked."
}
are you sure you connected the code correctly?
Related
In all cases, I can wire user-interface buttons to actions with Interface Builder. But the buttons work for Objective-C but not for Swift.
Objective-C example (it works):
- (IBAction)TogglePlaying:(id)sender {
(details snipped for brevity)
}
Swift example (it doesn't work, though it's wired to its button):
#IBAction func Go(_ sender: Any) {
print("Going")
OutputText!.stringValue = InputText!.stringValue
}
I have no idea of what the difference might be, because everything I've found on using IBAction in Swift indicates that I've written it correctly. Also, in Interface Builder, I've set File's Owner's Custom Class correctly.
Update:
Using
ios - Find what Action is called by a Button in interface builder in debug mode - Stack Overflow
Find what Action is called by a Button in interface builder in debug mode
I used "Debug View Hierarchy", right-clicked on "NSButton - Go!" in the widget-hierarchy view, and selected "Print Description of NSButton - Go!"
I got
Printing description of $13:
<NSButton: 0x7fac1b116250>
I then did:
po [0x7fac1b116250 allTargets]
error: Execution was interrupted, reason: Attempted to dereference an invalid ObjC Object or send it an unrecognized selector.
The process has been returned to the state before expression evaluation.
Update:
I tried
po [0x7faf38011790 target]
(new address of that button) and I got
nil
Update:
The complete code of TLWindow, in Swift:
import Cocoa
class TLWindow: NSWindowController {
#IBOutlet weak var InputText: NSTextField!
#IBOutlet weak var OutputText: NSTextField!
override var windowNibName: NSNib.Name? {
return NSNib.Name("TLWindow")
}
#IBAction func Go(_ sender: Any?) {
print("Going")
OutputText!.stringValue = InputText!.stringValue
}
}
I don't know how to show that the xib is wired up correctly without doing a lot of screenshots. But it is, with the "Go!" button connected to "Go:" in "File's Owner". Also, "File's Owner" is set to "TLWindow", this class.
You are creating an instance of TLWindow in newDocument(), but then you're letting it go out-of-scope...
Try this:
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
// add a property to "hang onto" the instance
var myTLWindow: TLWindow!
func applicationDidFinishLaunching(_ aNotification: Notification) {
// Insert code here to initialize your application
newDocument(self)
}
// Create an app window
#IBAction func newDocument(_ sender: Any?) {
let wc = TLWindow()
// add this line
myTLWindow = wc
wc.showWindow(self)
}
}
I am making an iMessage extension that uses the didTransition(to:). However, the function won't run when I resize the iMessage extension in the simulator. Am I doing something wrong?
This is the code I have:
import UIKit
import Messages
class EditorViewController: MSMessagesAppViewController {
#IBOutlet weak var input: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
input.text = "not changed"
}
// This part isn't working:
override func didTransition(to presentationStyle: MSMessagesAppPresentationStyle) {
input.text = "changed"
}
}
When I resize it in the simulator, nothing happens. The input.text changes the UITextView's text in the viewDidLoad() function, but not in the didTransition(to) function because it never runs.
Am I doing something wrong?
The EditorViewController is a view controller presented by the show (e.g. Push) segue, and has a NavigationController attached to it.
Here is a gif of it not changing:
The input's text never changes
How can I fix this?
EDIT: The willTransition and didTransition functions don't run when the View Controller is embedded in a Navigation Controller. Is there a way to fix this? (It works without the Navigation Controller, but I need the Navigation Controller for this project).
As pointed out in this answer, the entry point of a iMessage App need to be a subclass of MSMessagesAppViewController, so you can not use a NavigationViewController directly as root controller, until Apple adds support for this behavior.
But as suggested, you could solve this with a workaround like this:
import UIKit
import Messages
class MyRootVC: MSMessagesAppViewController {
var navVC: UINavigationViewController!
var editorVC: EditorViewController!
func viewDidLoad() {
super.viewDidLoad()
editorVC = UIStoryboard(name: "Main", bundle: nil).instantiateInitialViewController() as! EditorViewController
navVC = UINavigationController(rootViewController: editorVC)
self.addChild(navVC)
self.view.addSubview(navVC.view)
navVC.didMove(toParent: self)
}
override func didTransition(to presentationStyle: MSMessagesAppPresentationStyle) {
editorVC.input.text = "changed"
}
}
class EditorViewController: UIViewController {
#IBOutlet weak var input: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
input.text = "not changed"
}
}
This question already has answers here:
(NSMenuItem): missing setter or instance variable
(3 answers)
Closed 4 years ago.
Tutorial for Hello World
I tried using the tutorial, link described above which was going until the execution but when i use the button click to display the name it show some error
Failed to connect (sayButtonClicked) outlet from
(HelloWorld.ViewController) to (NSButton): missing setter or instance
variable
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var nameField: NSTextField!
#IBOutlet weak var helloLabel: NSTextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func sayButtonClicked(_ sender: Any) {
var name = nameField.stringValue
if name.isEmpty{
name = "World"
}
let greeting = "Hello\(name)!"
helloLabel.stringValue = greeting
}
}
It sounds like you have an outlet connection in your storyboard named "sayButtonClicked" but "sayButtonClicked" is an IBAction, not an outlet. Try doing the following:
Delete that "sayButtonClicked" outlet from your storyboard.
Open your storyboard in the editor and the source-code for the view controller in an "assistant editor"
Control-drag from the dot next to your IBAction in your code onto the button in your storyboard. This will connect the action to the button. You may need to select "touch up inside" as the event you want to trigger the action.
Disclaimer: I am teaching myself Swift & Xcode so my question is rather simple.
I'm building a simple application to get started, which has a text field connected to a String output.
The lesson I'm on currently has an excerpt which reads:
"The reset method simply needs to clear out the text of both the nameField and the lyricsView—you can do this by setting each of their text properties to an empty string."
I understand this probably involves an if statement, but I think the explanation on this is rather poor.
Here's the viewcontroller:
class ViewController: UIViewController {
#IBOutlet weak var nameField: UITextField!
#IBOutlet weak var lyricsView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func reset(_ sender: Any) {
}
#IBAction func displayLyrics(_ sender: Any) {
}
}
Can someone explain what they mean by setting the properties of nameField and lyricsView to an empty string in order to reset?
Thanks!
If you want to clear the text of a textField or a textView, just set the text property to an empty string. As your lesson hint:
The reset method simply needs to clear out the text of both the
nameField and the lyricsView—you can do this by setting each of their
text properties to an empty string.
The reset method should like this:
#IBAction func reset(_ sender: Any) {
nameField.text = ""
lyricsView.text = ""
}
To clear those fields I'd use:
#IBAction func reset(_ sender: Any) {
nameField?.text = ""
lyricsView?.text = ""
}
The question mark will safely execute the code even if, for some reasons, those fields are not loaded yet, or have been freed or removed.
ADD this to reset method to remove the content:-
nameField.text = ""
lyricsView.text = ""
When you enter something into nameField something shows up in your lyricsView. So, there should be a way to clear what you've entered (and what is displayed). Hence, the reset function (I guess it's bound to a button).
Once you hit reset the text in nameField and lyricsView should disappear. You can do this by assigning both to something called an empty string, which is just two double-quotes:
let anEmptyString = ""
You'd need to assign the "" to the nameField and lyricsView text property.
Using Swift only, here's my code in AppDelegate.swift:
import Cocoa
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet var window: NSWindow
#IBOutlet var textField: NSTextView
#IBAction func displaySomeText(AnyObject) {
textField.insertText("A string...")
}
func applicationDidFinishLaunching(aNotification: NSNotification?) {
// Insert code here to initialize your application
}
func applicationWillTerminate(aNotification: NSNotification?) {
// Insert code here to tear down your application
}
}
In the interface builder, I have an object hooked up to receive input from a button, then the output goes to a text view. I'm trying to get the text view to populate with some text when I hit the button.
I tried this with a text field as well, and didn't get the error, but got a "dong" error sound and it didn't do anything else. In Objective-C, you had to use the (assign) parameter to get this to work from what I understand.
What am I doing wrong?
You cannot store a weak reference to an NSTextView due to historical issues with Cocoa and AppKit. See details in the Clang documentation. NSTextView is marked as NS_AUTOMATED_REFCOUNT_WEAK_UNAVAILABLE in NSTextView.h, there are also a few other classes to lookout.
Have you tried a Swift unowned reference instead of weak, which is kind of like Objective-C's assign (what you'd use for an NSTextView outlet in Objective-C)?
Use #IBOutlet var scrollView: NSScrollView instead of #IBOutlet var textField: NSTextView.
Then create a property returns documentView in scrollView.
import Cocoa
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet var window: NSWindow
#IBOutlet var scrollView: NSScrollView
var textField: NSTextView {
get {
return scrollView.contentView.documentView as NSTextView
}
}
#IBAction func displaySomeText(AnyObject) {
textField.insertText("A string...")
}
func applicationDidFinishLaunching(aNotification: NSNotification?) {
// Insert code here to initialize your application
}
func applicationWillTerminate(aNotification: NSNotification?) {
// Insert code here to tear down your application
}
}
I have tried to replicate what you described. I have created a new OS X app using Xcode 6 beta 7. I have dropped a button and text view in the main form.
I think your problem is that the connection to the Text View object is not correct for some reason. To make things easier, I've connected the objects using control-drag, which adds the required code automatically. So first I've connected the Text View. To do this click on the text view object until Text View is selected. When I do this in my version of Xcode, the first time I click on the object, Bordered Scroll View is selected. Clicking on it again then selects Clip View. Finally, clicking on it again selects Text View. Now I control-drag from the object to the AppDelegate.swift code (It helps to display the Assistant Editor so that you have your form UI and code side-by-side).
By doing this I get this little window:
Notice that the type is NSTextView and the storage is Weak. I've only had to add the name and click Connect. This adds the following code in AppDelegate.swift:
#IBOutlet var textField: NSTextView!
The code is almost exactly like the one you have, except for the ! at the end of the line, which forces to unwrap the value of textField.
Just with that, the code as you have it in your question should work.
The other thing I would suggest is not to use insertText. According to Apple's documentation for NSTextView.insertText:
This method is the entry point for inserting text typed by the user
and is generally not suitable for other purposes. Programmatic
modification of the text is best done by operating on the text storage
directly.
As far as I understand this, programmatic modification of the text by operating on the text storage directly means dealing with NSText, which NSTextView inherits from. So instead, use NSText.string. This is how the click button action looks in my code:
#IBAction func displaySomeText(sender: NSButton) {
// If you want to add a new 'A string... ' every time you click the button
textField.string! += "A string... "
// otherwise just use
//textField.string = "A string..."
}
I have added the Button Action in the same way as I've added the Text View Outlet, by control-dragging, and, in this case, selecting NSButton as the sender, instead of leaving the default AnyObject.
#IBOutlet automatically makes a property weak IIRC, but weak doesn't automatically make a property optional. But it is required that a weak property be made optional, as the property could at any time be deallocated and made nil. So you have to declare your #IBOutlets as optional.
import Cocoa
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet var window: NSWindow? // Optional
#IBOutlet var textField: NSTextView?
#IBAction func displaySomeText(AnyObject) {
textField?.insertText("A string...") // Only call the method if the object exists
}
func applicationDidFinishLaunching(aNotification: NSNotification?) {
// Insert code here to initialize your application
}
func applicationWillTerminate(aNotification: NSNotification?) {
// Insert code here to tear down your application
}
}
Does the "dong" error suggest a responder chain problem? What if you call becomeFirstResponder on the text field before inserting the text?
To create a weak reference user the weak keyword:
example:
#IBOutlet weak var myView: UIView
In your case
#IBOutlet weak var textField: NSTextView