Question

I am missing something simple here, please help me understand what.

My Controller sets up

UIGestureRecognizer *swipe = [[UIGestureRecognizer alloc] 
          initWithTarget:gameView action:@selector(handleSwipeFrom:)];
[gameView addGestureRecognizer:swipe];

The GameView is set up

@interface GameView : UIView<UIGestureRecognizerDelegate> 

It further declares

- (IBAction) handleSwipeFrom:(UISwipeGestureRecognizer*)recognizer;

and sets it up as

- (IBAction)handleSwipeFrom:(UISwipeGestureRecognizer*)recognizer {
    NSLog(@" ..............  Swipe detected!! ...................");
}

The Storyboard links UIGestureRecognizer with this IBACtion and is set up as follows:

I am a little concerned that UIGestureRecognizer appear underneath a Controller and not the view as shown, but i can’t seem to be able to correct it.

When application is built, swipes, however are not recognized.

Please suggest what i am missing here and whether i am going the right way about setting things up.

Answer 1

You are setting up two separate gesture recognizers. One in code which likely does nothing, the other in the storyboard that likely has no target.

In code you should initialize a swipe gesture recognizer like so:

UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:gameView action:@selector(handleSwipeFrom:)];
 // And assuming the "Up" direction in your screenshot is no accident
swipe.direction = UISwipeGestureRecognizerDirectionUp;

Or, of course, you could connect the swipe recognizer in the storyboard. This is easily done by either right clicking on the gesture recognizer and connecting the SentActions to the handleSwipeFrom: method, or similarly you can drag from the connections inspector on the right (as seen in screenshot) to the named function. In the image you can see I have my Sent Actions connected to the method swipeTarget:.

But currently you have two incomplete recognizers.