将滚动事件传递给uiviewview中的uiimageview，并将其添加为要查看的子视图

Question

I have added one scrollview and imageview to my view. When I touch on this imageview my scrollview scrolls. And within my scrollview there are lots of imageviews which have touch events written separately.

Here is the view hierarchy

                          View
                            |
                            |
                    -------   --------
                   |                  |
                imageView1         scrollview
                                       |
                                  ...........................
                                  |           |       |.....|
                                 imageviews2

Imageview1 is above imagesview2 in appearance.

And when I scroll the scrollview it is not possible to touch some of the imageViews within the scrollview as it comes behind the imageview within view.

How can I pass the touch events to the imageviews2 whenever it is behind imageview1.

Answer 1

You need to pass the touch event to the UIViews that are outside the bounds of the parent view.

- (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];
}

https://developer.apple.com/library/ios/qa/qa2013/qa1812.html

Answer 2

You'll need to subclass UIView and override

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

in that subclass to skip imageView1.

You might get away with subclassing UIImageView and instantiating imageView1 as a member of that class, and overriding pointInside

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{ return NO; }

Answer 3

不要忘记在滚动视图上取消选中“延迟内容触摸”和“可取消的内容触摸”！

Answer 4

I hope this answer might be useful for someone. I have done it without using hittest.

Took all the subviews in scrollview and checked if it is an image view and did the following.

Passed the touchevents to another view using [view touchesBegan:touches withEvent:event]; we have to write the same in touchesMoved and touchesEnded also.

Thanks,

Joku