objective c - Get swipe direction in Cocoa Touch

Question

I am trying to catch a gesture but it does not work. Here is my code:

UISwipeGestureRecognizer *recognizer;
    recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFrom:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft)];
    [[self view] addGestureRecognizer:recognizer];
    [recognizer release]; 

and

-(void)handleSwipeFrom:(UISwipeGestureRecognizer *)recognizer {
    NSLog(@"get gesture");
    if (recognizer.direction == UISwipeGestureRecognizerDirectionRight) {
        NSLog(@"get gesture right");
    }
    if (recognizer.direction == UISwipeGestureRecognizerDirectionLeft) {
        NSLog(@"get gesture Left");
    }
}

It always gets a gesture but does not recognize the direction. I also tried if(recognizer.direction){NSLog(@"get gesture");} and it also worked, so I do not understand where I made the mistake.

Thanks for any help.

Answer 1

You're not using the UISwipeGestureRecognizercorrectly. Its direction is always going to be what you've set it to (in this case UISwipeGestureRecognizerDirectionRight | UISwipeGestureRecognizerDirectionLeft, or 3).

If you want to capture swipes left and right that you can differentiate between, you'll have to set up a separate recognizer for each. Apple does this in their SimpleGestureRecognizers sample.