UIView.为什么在其父级范围之外的子视图不会收到触摸？

Question

我有一个简单的 UIView 父/子层次结构。一位父级 (UIView)。一个孩子（UIButton）。父级边界小于子级边界，因此子级的一部分会超出其父级的边界框。

问题是：在父级的 bbox 之外的子级的那些部分不会接收触摸。只有在父级的 bbox 内点击才允许子级按钮接收触摸。

有人可以建议修复/解决方法吗？

更新

对于那些关注这个问题的人，这是我根据@Bastians最优秀的答案实现的解决方案：

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {

    BOOL isInside = [super pointInside:point withEvent:event];

    // identify the button view subclass
    UIButton *b = (UIButton *)[self viewWithTag:3232];
    CGPoint inButtonSpace = [self convertPoint:point toView:b];

    BOOL isInsideButton = [b pointInside:inButtonSpace withEvent:nil];

    if (isInsideButton) {

        return isInsideButton;

    } // if (YES == isInsideButton)

    return isInside;        
}

Answer 1

问题在于响应者链。当您触摸显示屏时，它会从父母向下移动到孩子。

所以..当您触摸屏幕时，父母会发现触摸超出了自己的范围，因此孩子们甚至不会询问。

执行此操作的函数是 hitTest。如果您有自己的 UIView 类，您可以覆盖它并自行返回按钮。

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event

Answer 2

根据 Apple 自己的文档，我拥有的最简单、最可靠的方法发现这样做的方法是在剪辑视图的超类中重写 hitTest:withEvent: ，如下所示：

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {

    // Convert the point to the target view's coordinate system.
    // The target view isn't necessarily the immediate subview
    CGPoint pointForTargetView = [self.targetView convertPoint:point fromView:self];

    if (CGRectContainsPoint(self.targetView.bounds, pointForTargetView)) {

        // The target view may have its view hierarchy,
        // so call its hitTest method to return the right hit-test view
        return [self.targetView hitTest:pointForTargetView withEvent:event];
    }

    return [super hitTest:point withEvent:event];
}

Answer 3

• @dugla，谢谢您的提问！
• @Bastian 和 @laoyur，感谢您的解答！

斯威夫特4

override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {

    if yourChildView.point(inside: convert(point, to: yourChildView), with: event) {
        return true
    }

    return super.point(inside: point, with: event)
}

Answer 4

前提条件：

您在 UIView（名为容器）内有一个 UIButton（名为 Button1），并且 Button1 部分位于容器边界之外。

问题：

button1容器外的部分不会响应点击。

解决方案：

从 UIView 子类化您的容器：

class Container: UIView {
    override func pointInside(point: CGPoint, withEvent event: UIEvent?) -> Bool {

        let closeButton = viewWithTag(10086) as! UIButton  //<-- note the tag value
        if closeButton.pointInside(convertPoint(point, toView: closeButton), withEvent: event) {
            return true
        }
        return super.pointInside(point, withEvent: event)
    }
}

不要忘记为您的 Button1 指定 10086 标签

Answer 5

我手头有同样的问题。您只需要覆盖：

-(BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event

以下是自定义 UIView 子类的工作代码，其创建的目的只是为了可点击其外部 -限制孩子。

@implementation ARQViewToRightmost

// We should not need to override this one !!!
/*-(UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    if ([self isInside:point])
        return self;
    return nil;
}*/

-(BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
    if ([self isInside:point])
        return YES; // That answer will make hitTest continue recursively probing the view's subviews for hit
    return NO;
}

// Check to see if the point is within the bounds of the view. We've extended the bounds to the max right
// Make sure you do not have any other sibling UIViews to the right of this one as they will never receive events
- (BOOL) isInside:(CGPoint)point
{
    CGFloat maxWidth = CGFLOAT_MAX;
    CGRect rect = CGRectMake(0, 0, maxWidth, self.frame.size.height);
    if (CGRectContainsPoint(rect, point))
        return YES;
    return NO;
}

@end