360 degree car rotation – common code for mobiles and computer browsers

I had been updating my examples and tutorials off  lately and trying to create a more general approach to application development – Write a single app that runs in mobile browsers as well as computer browsers. Following the same approach, this time I am updating one of my previous tutorials – 360 Degree Car/Product rotation for iPhones. So, I worked on a 36o degree car rotation code that runs in both mobile and desktop browsers.

This tutorial is an update to my previous one, I also present a new demo. I will not go into the details, which I have talked about in my previous tutorial. Have a look at the demo, open it in either an iOS browser or a computer web-kit browser.

Link: http://jbk404.site50.net/360DegreeView/mobile/common.html

360 degree car rotation in mobile safari

What are the changes?

All the changes are in the javascript code. I have introduced a device detection mechanism and then automatically assign either touch events (for mobiles) or mouse events (for computer browsers). These are the same changes that I have recently talked of in my last post – Replicating the iPhone Swipe Gesture — common code for mobiles and computer browsers. That should help you out.

Other than that just try the example link in a computer web-kit browser – Chrome/Safari or an iOS device browser which is also a web-kit browser. Android devices need some changes and the same code might not work. I have talked on this in my previous post.

For the code, right click to view the source.

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Replicating the iPhone Swipe Gesture – common code for mobiles and computer browsers.

This is another update for the iPhone Swipe Gesture that I have created. This is the third update to the series – Part 1 and Part 2. In case you have missed out of the earlier tutorials and detailed explanation then you can have a look at them first, before proceeding with this tutorial. What I have been able to achieve is that, I have replicated the native iPhone swipe gesture for the iPhone web-kit browser. So, throughout the series I have been able to create a HTML/JavaScript/CSS3 version of the swipe gesture. If in case, again you are not sure of the swipe gesture and swiping, I would recommend to go through my previous tutorials – Part1 and Part2.

Now, the update and the agenda of this tutorial is that – I have developed a common universal code for mobile browsers and computer browsers. Note that when I am saying browsers I mean web-kit browsers – Chrome & Safari in computers, and then the default web browsers in iOS and Android mobiles. The major changes are in the javascript code, where I have automated the user event handling process. What this means is that for mobile devices touch based events are registered and listened to and then for computer browsers mouse based events are registered and handled by the script automatically. This way there is no need to hard code touch events for mobiles and mouse events for computers. The same code works everywhere.

But, still to support different device screen sizes you will need to make changes to the CSS or the asset (images) sizes. The demo that I have worked on, I have considered the iPhone resolution – 320 x 416.

Check out the demo (same link works in mobiles and computers): http://jsphkhan.github.io/swipe_gesture_common/

An image/slide showing up in portrait mode
Common implementation for mobiles and computers

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Cooler modal Popup window with fade effect – gradient colors, border, drop shadow and center position

In one of my earlier post I talked on creating a cool modal pop up window using CSS3 and JavaScript. It had fade effect upon opening and closing of the pop up. Based on the same lines, I have created a much cooler pop up, actually asked by one of my readers. It now has gradient colors, much more eye catching – vibrant color 🙂, it has a header, a content area, border, drop shadow and it is also now centrally positioned always, even if you go from portrait to landscape mode and vice-versa.

Look at the demo first, you can view in both mobile web-kit browsers (iOS ,Android) and desktop browsers (Chrome, Safari):

http://rialab.jbk404.site50.net/coolermodalpopup/

The concept remains the same. I have discussed it in details in my previous post. Just refer that in case it is not clear. In this post, I will just talk briefly on the changes that I have implemented.

HTML changes
No major changes. I just externalized the CSS and JavaScript. So they are now in external files, which I reference in the index.html file. The HTML code is very simple and self explanatory. Download the code and check it out. A download link is provided below.

JavaScript changes
I have made some changes in the architecture of the popup creation. The showPopUpMessage() function now takes a header, main content, width and height parameters.

//show the modal overlay and popup window
function showPopUpMessage(modalWindowHeader,modalWindowContent,width,height) {
     //code goes here
}

Since this new pop up has a header, so I have kept a separate method for the header. You can call a function to create the header content and then set it in the showPopUpMessage() function. This will help if you have multiple instances of pop up to create. Here is the function,

/* Common header for Pop Ups */
function createPopUpHeader(title)
{
  //return the header after creating
  //create header for modal window area
  modalWindowHeader = document.createElement("div");
  modalWindowHeader.className = "modalWindowHeader";
  modalWindowHeader.innerHTML = "<p>" + title + "</p>";

  return modalWindowHeader;
}

Similarly, I have kept a separate function to create the contents of the modal pop up. You can customize the method and change the contents. Again, this will help in creating more than one pop up window. Here is how I have done it for this example,

function createPopUpContent(msg)
{
  //return the content after creating
  //create modal window content area
  modalWindowContent = document.createElement("div");
  modalWindowContent.className = "modalWindowContent";

  modalWindowContent.innerHTML = "<p style='text-align:center; margin-top:10px;'>" + msg + "</p>";
  //create the place order button
  okBtn = document.createElement("div");
  okBtn.className = "redBtn okBtn";
  okBtn.innerHTML = "<p>OK</p>";
  okBtn.addEventListener(endEvent,function(){ hidePopUpMessage(); },false);

  modalWindowContent.appendChild(okBtn);
  return modalWindowContent;
}

And now once I have the header and the content I can call the showPopUpMessage() function to launch the pop up,

showPopUpMessage(createPopUpHeader("This is a cool popup"),createPopUpContent("I am a cool modal pop up. I have gradient colors, border colors, drop shadow and I am always positioned at the center!!"),250,300);

I have passed a width of 250 and a height of 300. You can change it as per your requirement.

Positioning the modal pop up always at the center

This is done by calculating the window width and height and then subtracting it by the popup width and height and then dividing by 2. This is how I did it,

modalWindowElement.style.left = (window.innerWidth - width) / 2 + "px";
modalWindowElement.style.top = (window.innerHeight - height) / 2 + "px";

Now, to keep the window always at the center, even when you resize the browser window or move from portrait to landscape and then back to portrait, I have registered a window resize event listener and then calculate the left and top position again as we did above. You can find this is inside the handleResize() function.

//when window is resized
window.addEventListener("resize",handleResize,false); //resizing is useful only when popups are opened

And finally one more change. In this example, if you see at the top of the javascript file, I have detected if the device browser is touch enabled. And then accordingly I register touch based events for touch devices and mouse events for desktop devices. So this is a common code and you do not have to hardcode anything. I have a separate post for this, you can go through it.

Style changes
Only new class selectors have been added for the modal window header, modal window content, gradient buttons. Rest of them is pretty simple and understandable.

So this is it. This is a much cooler pop up, better looking than my previous boring and dull pop up. Hope you have enjoyed it. Check out the demo or download the code.

Download
Download the source code here.

Updates
1) How to open multiple pop ups from one page – Check this post.

Replicating the Swipe Gesture iPhone Gallery for mobile web – images linked to URL

Just a quick update. I have made little changes to the original demo so that now the images are clickable or rather tap-able. So when a user taps on an image he is redirected to a URL. You can specify separate URL’s of your choice for each image. The default behavior of the swipe gesture and replicating it is still there. I have just added the feature of linking the images to URL.

Try the demo in computer or mobile browser (webkit based browsers only): http://rialab.jbk404.site50.net/swipegesture/common/

Tap/Click on any image in the gallery to open a URL. Also you can swipe on the images.

What are the changes made?
On the HTML side, I added the URL’s to the <img /> element in the index.html file, I have added a custom attribute link.

<li>
<img src="img/1.jpg" width="100%" height="100%" link="http://www.google.com"/>
</li>
<li>
<img src="img/2.jpg" width="100%" height="100%" link="http://www.yahoo.com"/>
</li>

Similarly, all the other <img /> elements have a link attribute that specifies the URL to redirect when user taps on that particular image. Note that link is a custom attribute. You can add custom attributes to HTML elements.

On the script part
This is where a little understanding is required. In my previous posts – part1 and part2 I have discusses in details about the swipe gesture and how using touch events I have managed to achieve it. If you see the JavaScript code, I have registered touch events that listen to the user’s finger movements. So if you notice a swipe gesture is actually a combination of

Swipe Gesture = touch start + touch move + touch end

It is only in the touch end event listener that we manipulate the net distance moved and based on that we swipe the images. Now, since we also need a tap/click to URL feature for each image so if you directly add a redirection code in either touchstart or touchend event listeners then every time you try to swipe it will take to to a URL. And then even the swipe is affected. So as soon as you start to swipe it, it will redirect you to a URL, which is exactly what we do not want. Now, if you notice a tap event it is a combination of,

Image Tap (Tap to a URL) = touch start + touch end

So there is no touch move in a tap event for an image. So this is the concept that helps in making the Swipe as well as the Tap to URL work together. When a user swipes across the screen he is actually covering some net distance, so your start point is not same as the end point. But when you tap on an image your start point and end points are same before you release your finger. Hence in a tap the net distance is zero. So based on that I made changes to the event handler for touchend event in the script file,

swipey.wrapper.addEventListener("touchend", swipey.endHandler, false);

And then in the endHandler method I added this,

if(swipey.distanceX == 0) //if the intention is to tap on the image then open a link
{
  var link_url = event.target.getAttribute("link"); //read the link from <img /> element
  window.open(link_url,"_blank");
}

This checks if the net distance is zero. And if it is so, then it reads the link attribute value and then redirects the user to the URL specified by link.

To open links/URL in same window or page – use _self instead of _blank in window.open()

This is it, now the code is capable to handling both user swipes and user tap/click to URL. You can checkout the demo. To download the code follow the link given below.

Download code
You can download the source code here.

Updates/Other related posts
1) Creating a swipe gesture gallery – My initial post on the topic. You can start here.

2) Flickering issue in iPhone/iPod solved.
After the swipey demo was done I was observing a strange flickering issue of the images. If you see the demo link in an iPhone or iPod’s mobile safari browser you would notice it. Test case – swipe the images to the left and you would notice a black flicker on the right side of the browser for a brief moment. This is happening when you swipe all the image for the first time. Second time on wards it is not being seen. Finally I could solve the issue and made a small post on it with the new fixed demo. You can find it here.

3) Common code and example for mobiles and computer browsers – I have developed a common universal code for mobile browsers and computer browsers. Note that when I am saying browsers I mean web-kit browsers – Chrome & Safari in computers, and then the default web browsers in iOS and Android mobiles. The major changes are in the javascript code, where I have automated the user event handling process. What this means is that for mobile devices touch based events are registered and listened to and then for computer browsers mouse based events are registered and handled by the script automatically. This way there is no need to hard code touch events for mobiles and mouse events for computers. The same code works everywhere. Find the post here. There is a demo and also a download link.

4) Circular swipe gesture gallery – I have a new tutorial where I have talked about a circular swipeable gallery. So the images keep on looping. The tutorial also includes a new demo. Read it here.

5) Auto scrolling swipe gesture gallery – Sometimes users may want a auto scrolling gallery along with the normal swipe gesture feature. I have a new post with a demo. Read it here.

JavaScript Touch event or Mouse event – detect and handle according to device

You might have faced this issue before or even might have wondered – How to write a single piece of code that establishes correct event in the device i.e touch events for mobile web browsers and mouse events for desktop browsers. You need not hard code the events for your app code. Once you detect and handle those events, you can run your app everywhere – mobiles and computer browsers. Normally when we develop an app for mobile browsers we test it in a desktop browser, so if you have touch events hard-coded into your script then it is a pain to change the script and make it work for computer browsers(replacing touch events with mouse events) and then change it back again to touch for mobiles. So, here is a small script/trick to universally handle the event and need not worry about devices,

var isTouchSupported = 'ontouchstart' in window;
var startEvent = isTouchSupported ? 'touchstart' : 'mousedown';
var moveEvent = isTouchSupported ? 'touchmove' : 'mousemove';
var endEvent = isTouchSupported ? 'touchend' : 'mouseup';

If you see the first line of the script, it detects if ontouchstart property is available in the global window object. It it is available or it is a part of the window object, then it returns true else it returns false. Note that ontouchstart is a standard javascript touch event attribute. Now, if you are making this check in a computer browser (for e.g FF, Chrome or IE) then ontouchstart is not a property of the window object. So isTouchSupported will be set to false. Had it been a mobile browser (e.g iOS, Android) then ontouchstart would have been automatically a part of the window object and correspondingly isTouchSupported variable will set to true. This is all we need to detect. The next three lines establish a common platform for the touch vs mouse events i.e I am mapping the touch events to its corresponding mouse events.

Now, all you need is to register the event listener to your element so that some action is performed when the event is triggered on the element. Here is an example, (where myButton is the ID of my imaginary button)

document.getElementById("myButton").addEventListener(startEvent,function(){},false);

The startEvent variable acts as a placeholder. It will be replaced by mousedown for computer browsers and touchstart for mobile browsers. Similarly the other two events can be used. This way a single app can run everywhere.

Here is a good example with the usage (make sure you look at the javascript script code) – https://jbkflex.wordpress.com/2012/07/21/replicating-the-iphone-swipe-gesture-common-code-for-mobiles-and-desktop-browsers/

Here is another one – https://jbkflex.wordpress.com/2012/07/25/360-degree-car-rotation-common-code-for-mobiles-and-computer-browsers/

Please do suggest me if there are any better methods of mapping touch v/s mouse events.