为什么Bezier曲线在iOS UIView中成为一种形状？

Question

我试图在iOS UIView中绘制Bezier曲线。我的代码是这样的：

UIBezierPath *curvePath = [UIBezierPath bezierPath];
[curvePath moveToPoint:_startPoint];
[curvePath addCurveToPoint:_endPoint controlPoint1:_controlPoint1 controlPoint2:_controlPoint2];
[[UIColor blueColor] setStroke];
curvePath.lineWidth = 8;
[curvePath stroke];
_drawingLayer = [CAShapeLayer layer];
_drawingLayer.path = curvePath.CGPath;
[self.view.layer addSublayer:_drawingLayer];

我期待蓝色的 弯曲贝塞尔线 ，但结果却是 封闭的黑色形状 像这样： 我的代码有什么问题吗？感谢。

Answer 1

您将手绘与CAShapeLayer混合在一起。如果您正在使用形状图层，则需要对其进行配置，而不是尝试自己绘制路径。例如：

UIBezierPath *curvePath = [UIBezierPath bezierPath];
[curvePath moveToPoint:_startPoint];
[curvePath addCurveToPoint:_endPoint controlPoint1:_controlPoint1 controlPoint2:_controlPoint2];
_drawingLayer = [CAShapeLayer layer];
_drawingLayer.path = curvePath.CGPath;

/* Configure the layer, not the current context */
_drawingLayer.strokeColor = UIColor.blueColor.CGColor;
_drawingLayer.lineWidth = 8;

[self.view.layer addSublayer:_drawingLayer];