绘图圆没有填写IOS

我正在使用这段代码在UI ImageView中画一个圆.

CAShapeLayer *circleLayer = [CAShapeLayer layer];
// Give the layer the same bounds as your image view
[circleLayer setBounds:CGRectMake(0.0f,0.0f,[photoView bounds].size.width,[photoView bounds].size.height)];
// Position the circle anywhere you like,but this will center it
// In the parent layer,which will be your image view's root layer
[circleLayer setPosition:CGPointMake(coordsFinal.x + 130,coordsFinal.y + 200)];
// Create a circle path.
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:
                      CGRectMake(0.0f,50.0f,50.0f)];
// Set the path on the layer
[circleLayer setPath:[path CGPath]];
// Set the stroke color
[circleLayer setStrokeColor:[color CGColor]];
// Set the stroke line width
[circleLayer setLineWidth:2.0f];

// Add the sublayer to the image view's layer tree
[[photoView layer] addSublayer:circleLayer];

我希望圈子是空的,只有边界.如何清除填充？

[circleLayer setFillColor:[[UIColor colorWithWhite:0 alpha:0] CGColor]];

[circleLayer setFillColor:[[UIColor clearColor] CGColor]];