I am attempting to create an app in Swift using a Storyboard. I want to have a button trigger the UIProgressView's animation.
*Expected '{' in body of function declaration*
import Cocoa
class ViewController: NSViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override var representedObject: AnyObject? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func PressKit(sender: AnyObject) {
func startAnimating()
}
}
If you are trying to call the function "startAnimating", then don't use the "func" keyword in front of it, just use "startAnimating()" to call the function. You will then need to define the function (outside of the "PressKit" function). You might want to do this somewhere else in the class using, say:
func startAnimating() {
...some code...
}
Related
I want to create an login template in a normal class,but in the class,the view can't call the event,no "sss" be printed when the Event triggered
import UIKit
class ViewController: UIViewController ,UITextFieldDelegate{
override func viewDidLoad() {
super.viewDidLoad()
let loginView=login(view: self.view,controller:self)
loginView.setView();
}
}
import UIKit
class login{
let PassWord=UITextField()
let view:UIView!
let controller:ViewController
init(view:UIView,controller:ViewController){
self.view=view
self.controller=controller
}
func setView(){
initPassWord()
print("1")
}
func initPassWord(){
PassWord.placeholder="PassWord"
PassWord.addTarget(self, action: #selector(login.exits(_:)), for:.allEvents)
//PassWord.addTarget(controller, action: #selector(login.exits(_:)), for:.allEvents)
}
#IBAction func exits(_ sender:UITextField){
print("sss")
}
You need
var loginView:Login! // hold a strong reference here , start class names with capital letter
override func viewDidLoad() {
super.viewDidLoad()
loginView = Login(controller:self)
loginView.setView();
}
Also make it weak
weak var controller:ViewController
as not to cause retain cycles
BTW you only need to send the controller , and there you can access it's view
I have a singleton to store some global data for my macOS app, one of my ViewController keeps modifying data. I want to simultaneously show the changes in a View, which is related to another ViewController. what 's the best way to do this?
Global Data:
final class AppData {
static var logs: [LogData] = []
}
ViewController 1:
class FirstViewController: NSViewController {
AppData.logs.append(newLogData)
}
ViewController 2:
class SecondViewController: NSViewController {
// what's the best way to simultaneously watch the change of AppData.logs?
}
If your App is planned to be macOS only you can use a NSObjectController. This is definitively the easiest approach and you can do most of the configuration in Interface builder. It works internally with bindings. In case of an array you want to observe, you would use a NSArrayController.
One way is to use the notificationcenter
In viewcontroller2 add:
override func viewDidLoad() {
super.viewDidLoad()
notificationCenter.default.addObserver(self,
selector: #selector(view1DidChange),
name: "view1DidChange",
object: nil
)
}
#objc private func view1DidChange(_ notification: Notification) {
// Do something
}
In viewcontroller1 add
notificationCenter.default.post(name: "view1DidChange", object: self)
This can be repeated in every class, that should listen.
Here i am sharing the Delegate & Protocol approach to achieve this functionality.
final class AppData {
static var logs: [LogData] = []
}
protocol FirstViewControllerDelegate {
func ViewControllerDelegate(appData:[LogData])
}
class FirstViewController: NSViewController {
var delegate:FirstViewControllerDelegate?
override func viewDidLoad() {
super.viewDidLoad()
AppData.logs.append(newLogData)
self. delegate?.ViewControllerDelegate(appData: AppData.logs)
}
}
class SecondViewController: NSViewController,FirstViewControllerDelegate {
var firstViewController:FirstViewController = FirstViewController()
override func viewDidLoad() {
self.firstViewController.delegate = self
}
func ViewControllerDelegate(appData:[LogData]){
//Do Update the UI
}
}
The use of autoreleasepool{} in swift is as follows.
autoreleasepool {
// all usage here
}
But I do not know how to use it in public.
Example
class ViewController: UIViewController {
autoreleasepool {
var results: Results<Item>!
}
override func viewDidLoad() {
super.viewDidLoad()
.....
}
}
If this is public, an error occurs. Does autoreleasepool{} need to be in func only?
In the code below, which (I hope) includes all that's relevant to my question, a mouseEntered/-Exited event in ChangerView is supposed to change the display in ChangingView. (ChangerView and ChangingView are displayed side-by-side and share a view controller.) As an OOP newbie, though, I'm seriously missing something about how to set up delegation between these views. Here's ChangerView (in which DoThis?.show = nil, despite that I thought I was setting it to true or false):
import Cocoa
protocol DoThis { var show: Bool { get set } }
class ChangerView: NSView {
var changeDelegate: DoThis?
// Set up for mouseEntered/-Exited
override func mouseEntered(theEvent: NSEvent) { DoThis?.show = true }
override func mouseExited(theEvent: NSEvent) { DoThis?.show = false }
}
And here's changing view:
import Cocoa
class ChangingView: NSView, DoThis {
var show: Bool = false { didSet { needsDisplay = true } }
// Draw into the view
override func drawRect(dirtyRect: NSRect) {
switch show {
case true: // Display setup contingent on show = true
case false: // Display setup contingent on show = false
}
// Draw contingent display
}
}
As I understand things, views should do their own basic display work, and view controllers should handle model-related and higher-level display changes. For that reason, and to keep things simple, I want ChangerView and ChangingView to communicate directly. Unfortunately, I couldn't find any explanations about delegation close enough to this situation—at least not that I could understand.
What am I missing (besides a properly functioning brain)?
Thanks!
It looks like there are two issues.
In your ChangerView class, you should be using the delegate to set the show variable, like this:
import Cocoa
protocol DoThis { var show: Bool { get set } }
class ChangerView: NSView {
var changeDelegate: DoThis?
// Set up for mouseEntered/-Exited
override func mouseEntered(theEvent: NSEvent) { changeDelegate?.show = true }
override func mouseExited(theEvent: NSEvent) { changeDelegate?.show = false }
}
You may want to make the delegate variable weak to prevent reference cycles
The other issue is you've forgot the step where you assign the delegate. I (and I think everyone else) forget this often. Once you get used to setting up delegates you'll remember to check for it if things don't work at first.
So at some point you need to set the changeDelegate var to an instance of the ChangingView class (this is often done in the viewDidLoad() function.
It will look something like this:
class SomeViewController: UIViewController {
#IBOutlet weak var SomeChangerView: ChangerView!
#IBOutlet weak var SomeChangingView: ChangingView!
override func viewDidLoad() {
super.viewDidLoad()
SomeChangerView.changerDelegate = SomeChangingView
}
I want to touch a button in ViewController and run a simple function in a custom class. No parameters needed. Code is basically:
class MyClass: UIView {
//init function is here
//other setup stuff
...
func SetFocus() {
//I want to set the camera focus to infinity.
var error: NSErrorPointer = nil
var pos: CFloat = 1.0
captureDevice!.lockForConfiguration(error)
captureDevice!.setFocusModeLockedWithLensPosition(pos, completionHandler: nil)
captureDevice!.unlockForConfiguration()
}
}
and in ViewController
import UIKit
class ViewController: UIViewController {
#IBOutlet var myClass: MyClass!
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 myButton(sender: UIButton) {
myClass.SetFocus()
}
}
I've tried everything I can think of (new at Swift) and the app either crashes or the function I'm calling doesn't run. Everything else in MyClass works OK.
Try to delete the #IBOutlet from before MyClass.
var myClass : MyClass!
You can also try this:
var myClass : MyClass! = MyClass()
From the looks of it, however, everything you are doing in setFocus() in MyClass, can easily be recreated in the ViewController.
Try this
#IBAction func myButton(sender: UIButton) {
var ClassViewController = self.storyboard.instantiateViewControllerWithIdentifier("StoryboardID") as! UIViewController
ClassViewController.MyFunction()
}