UIPanGestureRecognizer top level view not getting events, subviews consuming them - ios

Question

Using UIPanGestureRecognizer & UITapGestureRecognizer on top-level UIView.
The setup in Interface Builder:
ViewController (our main view controller)
UIView (our main view and wired to our UIViewController
Our core UIView has a subview called a “Block” which is simply a UIView.
The Block view has 4 subviews (children) each being an instance of a UIButton.
The UIButton has its Touch Up Inside event wired to the the UIViewController.
The UIView (our main top-level UIView) has a UIPanGestureRecognizer and a UITapGestureRecognizer
Here is the scenario we are trying to accomplish (a.k.a.The behavior):
A user taps a button (a cell).
The button will change its stated from “normal” to “selected”. (This works fine and the code is simple)
With a selected item, a user can place their finger anywhere on the screen an move it up or down
The issue:
Need to know when panning stops.
The top UIView does not receive a gesture stated of ended.
The UIView does not receive a touchesEnded event.
How do you know when the user has lifted their finger? Suppose I start the panning when my finger is over a UIButton, while panning occurs, the UIButton eats the touches begin and end events. Therefore, you have no way of knowing when the user stopped moving their finger across the iPhone/iPad glass.

Answer 1

First implement UIGestureRecognizerDelegate in your view controller.
Then set the delegate on your gesture recognizers to self and implement the following method
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
Your target method should look like this:
-(void)gestureRegognized:(UIGestureRecognizer*)gestureRecognizer
{
if ([gestureRecognizer isMemberOfClass:[UIPanGestureRecognizer class]])
{
//check its state
if(gestureRecognizer.state==UIGestureRecognizerStateBegan)
{
// add your code here
}
else if(gestureRecognizer.state==UIGestureRecognizerStateEnded)
{
// pan gesture ended code goes here
}
}
else if([gestureRecognizer isMemberOfClass:[UITapGestureRecognizer class]])
{
if(gestureRecognizer.state!=UIGestureRecognizerStateFailed)
{
// tap gesture detected
}
}
}