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PKCanvasView添加为子视图时不显示

pkcanvasview swift ios

Kevin Amiranoff · 技术社区 · 7 月前

我正试图将PKCanvasView集成到React Native应用程序中,但当我尝试添加 canvasView 作为子视图,它不会显示。只有我直接退货,它才有效。

这是我的密码。

// BBNativePencilManager.swift
// import PencilKit;

@objc(BBNativePencilManager)
class BBNativePencilManager: RCTViewManager {
  override func view() -> UIView {
//    let canvasView = PKCanvasView();
//    let drawing = PKDrawing()
//    canvasView.drawing = drawing;
//    if #available(iOS 14.0, *) {
//      canvasView.drawingPolicy = .anyInput
//    }
//    if (theme == "dark") {
//      canvasView.overrideUserInterfaceStyle = .dark;
//    } else {
//      canvasView.overrideUserInterfaceStyle = .light;
//    }
//    canvasView.isOpaque = false;
//    canvasView.backgroundColor = .clear;
//    canvasView.isMultipleTouchEnabled = true;
//    canvasView.backgroundColor = .yellow
//    canvasView.tool = PKInkingTool(.pen, color: UIColor.black, width: 5)
//    canvasView.becomeFirstResponder()
//    return canvasView;
//    The above code works correctly
    return BBNativePencilView(); // <-- this does not work
  }
  
  override static func requiresMainQueueSetup() -> Bool {
    return true
  }
}

和 BBNativePencilView

// BBNativePencilView.swift
import UIKit
import PencilKit


class BBNativePencilView: UIView {

  override init(frame: CGRect) {
    super.init(frame: frame)
    self.addSubview(canvas)
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
  
  lazy var canvas: PKCanvasView = {
    let canvasView = PKCanvasView()
    let drawing = PKDrawing.init()
    canvasView.drawing = drawing;
    if #available(iOS 14.0, *) {
      canvasView.drawingPolicy = .anyInput
    }
    canvasView.isOpaque = false;
    canvasView.backgroundColor = .clear;
    canvasView.isMultipleTouchEnabled = true;
    canvasView.backgroundColor = .yellow
    canvasView.tool = PKInkingTool(.pen, color: UIColor.black, width: 5)
    canvasView.becomeFirstResponder()
    return canvasView;
  }()
}

有人能向我解释一下这个问题吗?非常感谢。

1 回复 | 直到 7 月前

Anita 7 月前

这可能是由于将其添加为子视图时出现布局或框架问题。确保BBNativePencilView框架和画布框架设置正确。如果画布的框架设置不正确或太小,则画布可能不可见。

override init(frame: CGRect) {
    super.init(frame: frame)
    canvas.frame = self.bounds;
    canvas.autoresizingMask = [.flexibleWidth, .flexibleHeight];
    self.addSubview(canvas);
  }

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