UITapGestureRecognizer on transparent view

I have a tree with views where the highest level view is transparent and c开发者_StackOverflow社区ontains either an image or a label (with a transparent background).

When attaching a UITapGestureRecognizer to this view, I only get notifications on the views which contain images.

Also, if I leave the view empty, then I get events only when the background color is different than [UIColor clearColor].

I have done a dump and the entire view tree has userInteractionEnable = YES.

How can I get the UITapGesturerRecognizer to work on the view with a transparent background?

Solved

Problem was not what I thought. The transparent views were in a scroll view and during initialization they were outside of the view's visible area. Those within the visible area work ok.

Wild guesses here, but if you include a 1x1 pixel image in the view, would that view then qualify for gestures? Another equally wild guess would be to add a transparent image to the view and try that.

Try giving the view a nearly-transparent background color, like [UIColor colorWithWhite:0 alpha:0.01].

Try setting the background color to whatever except the clearColor and setting the alpha property to 0.0;

myView.backgroundColor = [UIColor blackColor];
myView.alpha = 0.0;