Pan Example

ViewController.m

//
//  ViewController.m
//  GestureRecognizers
//
//  Created by Ian MacKinnon on 2014-10-16.
//  Copyright (c) 2014 Ian MacKinnon. All rights reserved.
//

#import "ViewController.h"

@interface ViewController (){
    CGPoint startLocation;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UISwipeGestureRecognizer *swipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(didSwipe:)];
    swipeGesture.direction = UISwipeGestureRecognizerDirectionLeft;
    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(didPan:)];
    
    [self.view addGestureRecognizer:panGesture];
}

- (void)panGesture:(UIPanGestureRecognizer *)sender {
    CGFloat distance =0.0;
    if (startLocation.x != 0.0){
        CGPoint currentLocation = [sender locationInView:self.view];
        CGFloat dx = currentLocation.x - startLocation.x;
        CGFloat dy = currentLocation.y - startLocation.y;
        distance = sqrt(dx*dx + dy*dy );
        NSLog(@"Distance: %f", distance);
    }
    
    if (sender.state == UIGestureRecognizerStateBegan) {
        startLocation = [sender locationInView:self.view];
    } else if (sender.state == UIGestureRecognizerStateEnded) {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"YOU DONE SWIPED" message:[NSString stringWithFormat:@"%f", distance] delegate:nil cancelButtonTitle:@"ok" otherButtonTitles:nil];
        [alert show];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end