iOS 画圆圈

实线圆圈：

  CAShapeLayer *solidLine =  [CAShapeLayer
layer];

        CGMutablePathRef solidPath = 
CGPathCreateMutable();

        solidLine.lineWidth =
1.0f ;

        solidLine.strokeColor = [UIColor
grayColor].CGColor;

        solidLine.fillColor = [UIColor
clearColor].CGColor;

        CGPathAddEllipseInRect(solidPath,
nil, CGRectMake(10,
25, 72,
72);

        solidLine.path = solidPath;

        CGPathRelease(solidPath);

        [self.view.layer
addSublayer:solidLine];