Ios Swift TapGestureRecognitor和UIButton

我是Swift的新手，所以对于任何类型的错误我都很抱歉。 在我的视图控制器中，我有一个视图，CanvasView，我希望用户单击一个按钮并添加一个点击的形状。我创建了一个名为ShapeSquare的uiview，我有三个按钮和三种不同的形状。不幸的是，我不明白我错在哪里。这只是代码的一部分。 如有任何建议，将不胜感激

@IBOutlet weak var CanvasView: CanvasView!


override func viewDidLoad() {
    super.viewDidLoad()


    let tapGR = UITapGestureRecognizer(target: self, action: Selector(("didTap")))
    tapGR.numberOfTapsRequired = 1
    CanvasView.isUserInteractionEnabled = true
    CanvasView.addGestureRecognizer(tapGR)

}
func didTap(tapGR: UITapGestureRecognizer) {
    let tapPoint = tapGR.location(in: CanvasView)
    let shapeView = ShapeSquare(origin: tapPoint)
    CanvasView.addSubview(shapeView)

}


@IBAction func SquareShape(_ sender: UIButton) {
    CanvasView.setNeedsDisplay()       
}

一,-

二,-

let tapGR = UITapGestureRecognizer(target: self, action: #selector(didTap(_:)))

@objc func didTap(_ tapGR: UITapGestureRecognizer) {