Change Custom Views drawing when button is clicked in Swift OS X app

Question

So in my Swift OS X app I have one custom view and one button. When I start my app, my view shows a red oval and I need to change that drawing to drawRectangle()-method when i click my button.

My custom view's class MyView looks like following:

import Cocoa
import AppKit

class MyView: NSView {

    var isTrue = true

    override func drawRect(dirtyRect: NSRect) {
        super.drawRect(dirtyRect)

        // Drawing code here.
        if isTrue {
            DrawingMethods.drawOval()
        } else {
            DrawingMethods.drawRectangle()
        }

    }

    @IBAction func buttonPressed(sender: AnyObject) {

        isTrue = false
        // Now I need to update the view, so it draws rectangle isntead of oval. How I do that?

    }
}

And I have my DrawingMethods class:

import Cocoa

public class DrawingMethods: NSObject {

    public class func drawOval() {

        let color = NSColor(calibratedRed: 1, green: 0, blue: 0, alpha: 1)
        let ovalPath = NSBezierPath(ovalInRect: NSMakeRect(64, 54, 50, 45))
        color.setFill()
        ovalPath.fill()
    }

    public class func drawRectangle() {

        let color = NSColor(calibratedRed: 1, green: 0, blue: 0, alpha: 1)
        let rectanglePath = NSBezierPath(rect: NSMakeRect(136, 12, 34, 34))
        color.setFill()
        rectanglePath.fill()
    }
}

So how can i get my custom views draw rectangle instead of oval?

Answer 1

Call setNeedsDisplayInRect() on the view after setting isTrue = false. This will notify the view that it needs to redraw and drawRect will be called again.

Your buttonPressed function should be defined in the ViewController that contains the custom view

import Cocoa

class ViewController: NSViewController {
    @IBOutlet customView: MyView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    @IBAction func buttonPressed(sender: AnyObject) {
        customView.isTrue = false
        customView.setNeedsDisplayInRect(customView.bounds)
    }
}

---

Alternatively, you can just set the needsDisplay property of the view to true to redraw the entire view:

customView.needsDisplay = true