问题
I have an NSSlider
in FirstViewController
. I have 12 NSImageViews
in SecondViewController
. I'd like to move a slider in first window and shuffle images in these 12 views in second window.
How to update these NSImageViews
every time when moving the slider?
SecondViewController
var imagesQty = 100
override func viewWillAppear() {
super.viewWillAppear()
//let arrayOfViews: [NSImageView] = [view01,...view12]
for view in arrayOfViews {
let i = Int(arc4random_uniform(UInt32(imagesQty-1)))
let image = NSImage(data: try Data(contentsOf: photos[i]))
view.image = image
}
}
ViewController
@IBOutlet weak var slider: NSSlider!
@IBAction func segueData(_ sender: NSSlider) {
self.performSegue(withIdentifier: .secondVC, sender: slider)
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
if segue.identifier! == .secondVC {
if let secondViewController =
segue.destinationController as? SecondViewController {
secondViewController?.imagesQty = slider.integerValue
}
}
}
回答1:
First of all be aware that any move of the slider performs a new segue. To avoid that declare a boolean property which is set when the segue is performed the first time and could be reset after the second view controller has been dismissed.
To update the value in the second view controller keep the reference and call a method
Actually with this code you don't need the slider IBOutlet
class ViewController: NSViewController {
var secondControllerIsPresented = false
var secondController : SecondViewController?
...
@IBAction func segueData(_ sender: NSSlider) {
if !secondControllerIsPresented {
self.performSegue(withIdentifier: .secondVC, sender: sender)
secondControllerIsPresented = true
} else {
secondController?.updateArray(value: sender.integerValue)
}
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
if let identifier = segue.identifier, identifier == .secondVC {
let secondViewController = segue.destinationController as! SecondViewController
secondController = secondViewController
let slider = sender as! NSSlider
secondViewController.imagesQty = slider.integerValue
}
}
...
class SecondViewController: NSViewController {
...
func updateArray(value : Int) {
print(value)
}
Honestly I would use a button to perform the segue and move the slider into the second view controller. To shuffle the array use an Array
extension and as view an NSCollectionView
rather than a bunch of image views
来源:https://stackoverflow.com/questions/49524384/how-to-update-nsimageview-using-nsslider