Add swipe left/right to web page, but use default swipe up/down

Question

I'm using padilicious to detect swiping gestures for web pages that will be viewed on iOS and desktops. It works great to swipe left/right for previous and next pages of my site. However, it seems to override the default behavior in iPhone/iPad when swiping up/down. I'd like an up/down swipe to scroll the page, which it does when I don't have padilicious running. Just having the code ignore up/down swipes doesn't seem to work.

The section of padilicious code that I've been

function processingRoutine() {
    var swipedElement = document.getElementById(triggerElementID);
    if ( swipeDirection == 'left' ) {
        document.location = document.getElementById('nextPage').href;
    } else if ( swipeDirection == 'right' ) {
        document.location = document.getElementById('prevPage').href;
    } else if ( swipeDirection == 'up' ) {
        return;
    } else if ( swipeDirection == 'down' ) {
        return;
    }


}

Answer 1

Remove event.preventDefault(); from all functions. In the function processingRoutine() {} add event.preventDefault(); for what you want.

function processingRoutine() {
    var swipedElement = document.getElementById(triggerElementID);
    if ( swipeDirection == 'left' ) {
        // REPLACE WITH YOUR ROUTINES
        //swipedElement.style.backgroundColor = 'orange';
        event.preventDefault();
    } else if ( swipeDirection == 'right' ) {
        // REPLACE WITH YOUR ROUTINES
        //swipedElement.style.backgroundColor = 'green';
        event.preventDefault();
    } else if ( swipeDirection == 'up' ) {
        // REPLACE WITH YOUR ROUTINES
        //swipedElement.style.backgroundColor = 'maroon';
    } else if ( swipeDirection == 'down' ) {
        // REPLACE WITH YOUR ROUTINES
        //swipedElement.style.backgroundColor = 'purple';
    }
}

Answer 2

there's a jquery library, which does the job (by not providing up/down methods): http://plugins.jquery.com/project/Touchwipe-iPhone-iPad-wipe-gesture

Answer 3

I'm not familiar with padilicious, but check and see if the ontouchmove="BlockMove(event);" is set anywhere, that prevents the page from scrolling like you describe, I'm not sure how you would get it to keep the vertical scrolling but swipe horizontally.

Edit: I've since found a really helpful overview for doing "native" feel iOS web apps, it might not be exactly what you're looking for, but could provide you with another avenue of approach to your problem. Check it out: http://matt.might.net/articles/how-to-native-iphone-ipad-apps-in-javascript/

Answer 4

Padilicious seems to be preventing default in all cases. See the call to event.preventDefault() in all cases.

function touchStart(event,passedName) {
  // disable the standard ability to select the touched object
  event.preventDefault();

You will have to change start, stop, ... handlers to not call preventDefault() in up and down cases.

Answer 5

I changed the script, this work:

    // TOUCH-EVENTS SINGLE-FINGER SWIPE-SENSING JAVASCRIPT
// Courtesy of PADILICIOUS.COM and MACOSXAUTOMATION.COM

// this script can be used with one or more page elements to perform actions based on them being swiped with a single finger

var triggerElementID = null; // this variable is used to identity the triggering element
var fingerCount = 0;
var startX = 0;
var startY = 0;
var curX = 0;
var curY = 0;
var deltaX = 0;
var deltaY = 0;
var horzDiff = 0;
var vertDiff = 0;
var minLength = 72; // the shortest distance the user may swipe
var swipeLength = 0;
var swipeAngle = null;
var swipeDirection = null;

// The 4 Touch Event Handlers

// NOTE: the touchStart handler should also receive the ID of the triggering element
// make sure its ID is passed in the event call placed in the element declaration, like:
// <div id="picture-frame" ontouchstart="touchStart(event,'picture-frame');"  ontouchend="touchEnd(event);" ontouchmove="touchMove(event);" ontouchcancel="touchCancel(event);">

function touchStart(event,passedName) {
    // disable the standard ability to select the touched object
    //event.preventDefault();
    // get the total number of fingers touching the screen
    fingerCount = event.touches.length;
    // since we're looking for a swipe (single finger) and not a gesture (multiple fingers),
    // check that only one finger was used
    if ( fingerCount == 1 ) {
        // get the coordinates of the touch
        startX = event.touches[0].pageX;
        startY = event.touches[0].pageY;
        // store the triggering element ID
        triggerElementID = passedName;
    } else {
        // more than one finger touched so cancel
        touchCancel(event);
    }
}

function touchMove(event) {
    //event.preventDefault();
    if ( event.touches.length == 1 ) {
        curX = event.touches[0].pageX;
        curY = event.touches[0].pageY;
    } else {
        touchCancel(event);
    }
}

function touchEnd(event) {
    //event.preventDefault();
    // check to see if more than one finger was used and that there is an ending coordinate
    if ( fingerCount == 1 && curX != 0 ) {
        // use the Distance Formula to determine the length of the swipe
        swipeLength = Math.round(Math.sqrt(Math.pow(curX - startX,2) + Math.pow(curY - startY,2)));
        // if the user swiped more than the minimum length, perform the appropriate action
        if ( swipeLength >= minLength ) {
            caluculateAngle();
            determineSwipeDirection();
            processingRoutine();
            touchCancel(event); // reset the variables
        } else {
            touchCancel(event);
        }   
    } else {
        touchCancel(event);
    }
}

function touchCancel(event) {
    // reset the variables back to default values
    fingerCount = 0;
    startX = 0;
    startY = 0;
    curX = 0;
    curY = 0;
    deltaX = 0;
    deltaY = 0;
    horzDiff = 0;
    vertDiff = 0;
    swipeLength = 0;
    swipeAngle = null;
    swipeDirection = null;
    triggerElementID = null;
}

function caluculateAngle() {
    var X = startX-curX;
    var Y = curY-startY;
    var Z = Math.round(Math.sqrt(Math.pow(X,2)+Math.pow(Y,2))); //the distance - rounded - in pixels
    var r = Math.atan2(Y,X); //angle in radians (Cartesian system)
    swipeAngle = Math.round(r*180/Math.PI); //angle in degrees
    if ( swipeAngle < 0 ) { swipeAngle =  360 - Math.abs(swipeAngle); }
}

function determineSwipeDirection() {
    if ( (swipeAngle <= 45) && (swipeAngle >= 0) ) {
        swipeDirection = 'left';
    } else if ( (swipeAngle <= 360) && (swipeAngle >= 315) ) {
        swipeDirection = 'left';
    } else if ( (swipeAngle >= 135) && (swipeAngle <= 225) ) {
        swipeDirection = 'right';
    }

    /* else if ( (swipeAngle > 45) && (swipeAngle < 135) ) {
        swipeDirection = 'down';
    } else {
        swipeDirection = 'up';
    }*/
}

function processingRoutine() {
    var swipedElement = document.getElementById(triggerElementID);
    if ( swipeDirection == 'left' ) {
        // REPLACE WITH YOUR ROUTINES
        event.preventDefault();
        swipedElement.style.backgroundColor = 'orange';
    } else if ( swipeDirection == 'right' ) {
        // REPLACE WITH YOUR ROUTINES
        event.preventDefault();
        swipedElement.style.backgroundColor = 'green';
    } 

    /*else if ( swipeDirection == 'up' ) {
        // REPLACE WITH YOUR ROUTINES
        swipedElement.style.backgroundColor = 'maroon';
    } else if ( swipeDirection == 'down' ) {
        // REPLACE WITH YOUR ROUTINES
        swipedElement.style.backgroundColor = 'purple';
    }*/
}