iphone - quartz 圆图上的触摸事件？

Question

我使用带有填充的quartz 2d 在 iPhone 模拟器上画了一个圆圈。有没有办法可以检测到该圆圈上的触摸事件？

谢谢哈里坎特·贾米

Answer 1

如果您有该圆的 CGPath，则可以获取用户手指落在 TouchBegan 内的 CGPoint，并使用以下代码检查它是否落在该 CGPath 内。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
  UITouch *touch = [[event allTouches] anyObject];
  CGPoint location = [touch locationInView:self.view];
  // Depending on your code, you may need to check a different view than self.view

  // You should probably check the docs for the arguments of this function--
  // It's been a while since I last used it
  if (CGPathContainsPoint(yourCircle, nil, location, nil)) {
    // Do something swanky
  } else {
    // Don't do teh swank
  }
}