Question

I need to create jQuery mobile like Swipe gestures $("#slider ul li div").swipeleft(); using core jQuery without using any library or plugins not even jQuery mobile.

I know that jQuery mobile widgets are now going to be decoupled, so that we can take swipe alone from it. But I can’t wait for that long.

I need some manual jQuery code similar to swipe gestures for swipe left and right functions.
I’ve seen this, but i couldn’t understand how to get swipe gestures from it.
Can anyone help me out on that code?

Answer 1

This is the code for touch swipe using javascript. Finally I found it hard by searching all over the internet. Thanks to padilicious.Below is the HTML code for slider.

<div id="slider" ontouchstart="touchStart(event,'slider');" ontouchend="touchEnd(event);" 
ontouchmove="touchMove(event);" ontouchcancel="touchCancel(event);">
<ul id="slideul"><li><img src="1.jpg"></li><li>....</ul>
</div>

Below is the javascript code for the touch swipe. It’s bit long. But it works for me. You don’t have to change anything. Only place you have to change is processingRoutine() function. I’ve called 2 slide function i.e previous & next using this code sliders.goToNext() & sliders.goToPrev(). You can modify as you want..

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' ) {
        sliders.goToNext();         
    } else if ( swipeDirection == 'right' ) {
        sliders.goToPrev();
    } else if ( swipeDirection == 'up' ) {
        sliders.goToPrev();         
    } else if ( swipeDirection == 'down' ) {
        sliders.goToNext();         
    }
}