如何删除在 iOS 中绘制的圆圈？

Question

我有这段代码，我在屏幕上绘制圆圈，我想删除最后绘制的圆圈。我能做些什么？当我点击两次时，代码设置为画一个圆圈。我想删除点击一次时绘制的最后一个圆圈。

- (UIBezierPath *)makeCircleAtLocation:(CGPoint)location radius:(CGFloat)radius {

    iOSCircle *circle = [[iOSCircle alloc] init];
    circle.circleCenter = location;
    circle.circleRadius = radius;
    [totalCircles addObject:circle];

    UIBezierPath *path = [UIBezierPath bezierPath];
    [path addArcWithCenter:circle.circleCenter
                radius:circle.circleRadius
                startAngle:0.0
                endAngle:M_PI * 2.0
               clockwise:YES];

    return path;
}

- (IBAction) tapEvent: (UIGestureRecognizer *) sender
{

    CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    shapeLayer.path = [[self makeCircleAtLocation:location radius:2.5] CGPath];
    shapeLayer.strokeColor = [[UIColor redColor] CGColor];
    //shapeLayer.fillColor = nil;
    shapeLayer.lineWidth = 2.5;

    // Add CAShapeLayer to our view

    [self.view.layer addSublayer:shapeLayer];

    // Save this shape layer in a class property for future reference,
    // namely so we can remove it later if we tap elsewhere on the screen.

    self.circleLayer = shapeLayer;
    }

}

Answer 1

使用 CGPath 在不同的 CAShapeLayer 层中创建您的圈子，并将其添加为 view.layer 的子层。这样，您就可以完全控制该圈子（显示或隐藏它）。