Why can't I use other pencils or colors as expected in this app? It only draws a black color. This is my code:

import UIKit
import PencilKit
import PhotosUI
​
class ViewController: UIViewController, PKCanvasViewDelegate, PKToolPickerObserver {
​
    @IBOutlet weak var pencilButton: UIBarButtonItem!
    
    @IBOutlet weak var canvasView: PKCanvasView!
    
    let canvasWidth: CGFloat = 768
    let canvasOverScrollHeight: CGFloat = 500
    let drawing = PKDrawing()
​
    
    override func viewDidLoad() {
        super.viewDidLoad()
        canvasView.drawing = drawing
        canvasView.delegate = self
        canvasView.alwaysBounceVertical = true
        canvasView.drawingPolicy = .anyInput
        
        }
    
    
   override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
​
        let toolPicker = PKToolPicker()
        toolPicker.setVisible(true, forFirstResponder: canvasView)
        toolPicker.addObserver(canvasView)
        canvasView.becomeFirstResponder()
    }
   
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        
        let canvasScale = canvasView.bounds.width / canvasWidth
        canvasView.minimumZoomScale = canvasScale
        canvasView.maximumZoomScale = canvasScale
        canvasView.zoomScale = canvasScale
        
        updateContentSizeForDrawing()
        canvasView.contentOffset = CGPoint(x: 0, y: -canvasView.adjustedContentInset.top)
    }
    
    override var prefersHomeIndicatorAutoHidden: Bool{
        return true
    }
    
    @IBAction func fingerOrPencil (_ sender: Any) {
        canvasView.allowsFingerDrawing.toggle()
        pencilButton.title = canvasView.allowsFingerDrawing ? "Finger" : "Pencil"
    }
    
    
    @IBAction func saveToCameraRoll(_ sender: Any) {
        
        UIGraphicsBeginImageContextWithOptions(canvasView.bounds.size, false, UIScreen.main.scale)
        canvasView.drawHierarchy(in: canvasView.bounds, afterScreenUpdates: true)
        
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        if image != nil {
            PHPhotoLibrary.shared().performChanges({
                PHAssetChangeRequest.creationRequestForAsset(from: image!)
            }, completionHandler: {success, error in
            
            })
        }
    }
    
    
    
    func updateContentSizeForDrawing() {
        let drawing = canvasView.drawing
        let contentHeight: CGFloat
        
        if !drawing.bounds.isNull {
            contentHeight = max(canvasView.bounds.height, (drawing.bounds.maxY   self.canvasOverScrollHeight) * canvasView.zoomScale)
        } else {
            contentHeight = canvasView.bounds.height
        }
        canvasView.contentSize = CGSize(width: canvasWidth * canvasView.zoomScale, height: contentHeight)
    }
    
    // Delegate Methods
    
    func canvasViewDrawingDidChange(_ canvasView: PKCanvasView) {
       updateContentSizeForDrawing()
      
    }
    func canvasViewDidEndUsingTool(_ canvasView: PKCanvasView) {
        
    }
    func canvasViewDidFinishRendering(_ canvasView: PKCanvasView) {
        
    }
    func canvasViewDidBeginUsingTool(_ canvasView: PKCanvasView) {
        
    }
}

These are the outputs in the console:

2023-01-04 18:34:04.429420 0300 Drawing[45460:449613] [Assert] UINavigationBar decoded as unlocked for UINavigationController, or navigationBar delegate set up incorrectly. Inconsistent configuration may cause problems. navigationController=<UINavigationController: 0x123024000>, navigationBar=<UINavigationBar: 0x12140a0a0; frame = (0 47; 0 50); opaque = NO; autoresize = W; layer = <CALayer: 0x6000030afae0>> delegate=0x123024000
2023-01-04 18:34:04.468831 0300 Drawing[45460:449613] Metal API Validation Enabled
2023-01-04 18:34:04.705019 0300 Drawing[45460:449613] [ToolPicker] Missing defaults dictionary to restore state for: PKPaletteNamedDefaults
2023-01-04 18:35:00.196200 0300 Drawing[45460:449613] Keyboard cannot present view controllers (attempted to present <UIColorPickerViewController: 0x121846e00>)

CodePudding user response：

toolPicket released when out of method scope. You should have a instance of toolPicker in ViewController.

class ViewController: UIViewController {
  let toolPicker = PKToolPicker()
  ...
}

CodePudding user response：

i solved my problem by changing

toolPicker.addObserver(self)

into

toolPicker.addObserver(canvasView)

and adding the toolPicker at the top as @noppefoxwolf suggested