CODEWITHSUNDEEP
iphoneios
Maxime
Maxime

Reputation: 3165

Gesture detection on ios 3.1.3

In ios 3.1 and above how I can detect the Gesture in an UIView...

In ios >= 3.2.3 I use this code...(for example):

    UISwipeGestureRecognizer *oneFingerSwipeLeft = 
    [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeLeft:)] autorelease];
    [oneFingerSwipeLeft setDirection:UISwipeGestureRecognizerDirectionLeft];
    [[self view] addGestureRecognizer:oneFingerSwipeLeft];

    UISwipeGestureRecognizer *oneFingerSwipeRight = 
    [[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(oneFingerSwipeRight:)] autorelease];
    [oneFingerSwipeRight setDirection:UISwipeGestureRecognizerDirectionRight];
    [[self view] addGestureRecognizer:oneFingerSwipeRight];

Someone have an idea/example...

Thanks

Upvotes: 0

Views: 343

Answers (1)

Tommy
Tommy

Reputation: 100632

You're going to have to subclass the UIView (or implement the stuff within the view controller if the layout isn't too complicated) and track the gestures you want for yourself using ye olde UIResponder methods touchesBegan:withEvent:, etc.

For example:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    if(!trackingTouch && [touches count] == 1)
    {
        trackingTouch = [touches anyObject];
        startingPoint = [trackingTouch locationInView:relevantView];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    if(trackingTouch && [touches containsObject:trackingTouch])
    {
        CGPoint endingPoint = [trackingTouch locationInView:relevantView];
        trackingTouch = nil;

        if(endingPoint.x < startingPoint.x)
            NSLog(@"swipe left");
        else
            NSLog(@"swipe right");
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
     [self touchesEnded:touches withEvent:event];
}

// don't really care about touchesMoved:withEvent:

That's an imperfect solution because it assumes that all finger down to finger up progressions are necessarily swipes. You'll probably want to implement some sort of maximum time duration or track velocities in touchesMoved:withEvent: or check that the touch moved at least a minimum distance. I think it's because people were making different decisions for all of those sorts of things that Apple ended up providing the UIGestureRecognizers.

Upvotes: 2

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