Responding to touchesBegan in UIPickerView instead of UIView
cocoa-touch, iphone, objective-c, uipickerview
Solution
I've been searching for a solution to this problem for over a week. I'm answering you even if you're question is over a year old hoping this helps others.
Sorry if my language is not very technical, but I'm pretty new to Objective-C and iPhone development.
Subclassing UIpickerView is the right way to do it. But you've to override the `- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event` method. This is the method called whenever you touch the screen and it returns the view that will react to the touch. In other words the view whose `touchesBegan:withEvent:` method will be called.
The UIPickerView has 9 subviews! In the UIPickerView class implementation `- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event` won't return `self` (this means the `touchesBegan:withEvent:` you write in the subclass won't be called) but will return a subview, exactly the view at index 4 (an undocumented subclass called UIPickerTable).
The trick is to make the `- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event` method to return `self` so you have control over the `touchesBegan:withEvent:`, `touchesMoved:withEvent:` and `touchesEnded:withEvent:` methods.
In these methods, in order to keep the standard functionalities of the UIPickerView, you MUST remember to call them again but on the UIPickerTable subview.
I hope this makes sense. I can't write code now, as soon as I'm at home I will edit this answer and add some code.
Problem
I have a UIPickerView that gets faded out to 20% alpha when not in use. I want the user to be able to touch the picker and have it fade back in. I can get it to work if I put a touchesBegan method on the main View, but this only works when the user touches the View. I tried sub-classing UIPickerView and having a touchesBegan in there, but it didn't work. I'm guessing it's something to do with the Responder chain, but can't seem to work it out.