Niall's Blog

Quick Introduction

Over the past month or so, I have been using JQuery Mobile to build a HTML5 mobile/tablet front-end for a strength training website I've developed. While I have built native Android and iOS applications before (in Java and Objective-C, respectively) the promise of a single codebase which would work on most major platforms, as well as the ability to iterate quickly in HTML and JavaScript, was very appealing.

JQuery Mobile & HTML5

To build a mobile app using HTML5 and JavaSript, you will need to write quite a bit of JavaScript. However, the UI controls and handling for a touch device are quite different from a standard web application. You will therefore want to take advantage of some kind of existing mobile HTML5/JavaScript framework (unless you have a lot of time and want to write everything from scratch yourself). There are a number of choices out there: jQTouch, Sencha Touch etc.

I have been a fan of JQuery for many years, enjoying its minimalist philosophy and the excellent core and community-contributed features and plugins. JQuery made JavaScript development tolerable to me. So, having heard good things about JQuery Mobile from Chris McDonough (Author of the Pyramid Python Web Framework), I figured I'd give it a try.

JQuery Mobile & HTML5: 3 Advantages

1. Easy to learn and Quick to Iterate:

   After reading the JQuery Mobile docs and also reading the JQuery Mobile book from O'Reilly, I was able to build a working, rough version of my app over a weekend. That is with no prior HTML5 / JQuery Mobile experience. Compared to Android and iOS, it is far faster to build out your UI and logic using JQuery Mobile and HTML5 than either platform natively.

   I found the learning curve for Apple's Interface Builder quite steep, and it also takes time to learn the quirks of the Android layout system. Furthermore, it is quite complicated to hook up a list view (ListView on Android, UITableView on iOS) to a remote datasource, and have it looking pretty, with native code. Using JQuery Mobile, I was able to leverage all my existing JavaScript and HTML/CSS knowledge to do this very quickly. I didn't have to learn a whole new abstraction with adapters, delegates etc. I just wrote JQuery code.

2. Avoid App Store Approval Madness & Debug Build Hell:

   One of the most painful things in developing for mobile, which by definition means being on iOS, is dealing with the Apple App Store approval process. In order to get a native app to your iOS users, you must go through a lengthy process (days, possibly weeks). Not only must you jump through this hoop on initial release, but for each upgrade, also. This adds greatly to the complexity of the QA and release cycle, in addition to simply adding time. Since JQuery Mobile apps are merely a special type of web app, they inherit all the wonderful qualities of that environment: As soon as the user reloads your site, they are "upgraded" to the latest version. Pushing bugfixes and new features is instantaneous. Even on Android - which with much less stringent Market requirements is the Wild West compared to the Apple environment - it is still nice to simply have the users upgraded without even being aware it is happening.

   An extension to this is how easy it is to distribute beta/test builds to users. Simply tell them to point their browser at a URL and they have it! No DRM madness for iOS nor even APK distribution with Android to think about.

3. Cross-platform & cross-device:

   The fact that my app worked immediately on both Android and iOS - along with many other platforms - is a massive advantage. As an individual developer, it is a huge effort to maintain a separate code base for each platform. Writing a quality mobile application for a single platform is a full-time job, having to re-do that for each platform takes a lot of resources. The fact that my app will work on both my Android and iOS devices equally well is a huge bonus.

   Furthermore, especially with the massive proliferation of Android devices in all shapes and sizes, making your app look presentable on a huge variety of screen resolutions is a real challenge. For serious Android developers, device fragmentation in terms of screen size (scaling from the downright tiny to quite large) actually represents a considerable development cost. With the browser rendering your application in a way that looks reasonable on every device, you don't have to worry about this to anywhere near the same extent.

JQuery Mobile & HTML5: 3 Disadvantages

1. Slower Than Native:

   The biggest drawback in my opinion is that even on the latest Android and iOS hardware (dual core Tegra 2 Android phone, dual core iPad2 tablet), JQuery Mobile applications feel noticeably slower than native. Especially on Android, where the browser is surprisingly (since Google is a web-focused company) far slower and buggier than on iOS. I haven't yet tested my app on older Android devices but it may be downright unusable there (e.g. G1 Android phone).

   I believe that in the next 12-24 months hardware will catch up sufficiently (e.g. quad-core devices coming in 2011) that this will be less of an issue. But today, it is a definite drawback. Also, if you are solely targetting iOS, you can count on the performance of the browser being at least reasonable (unlike Android, BlackBerry, etc).

2. Quirky:

   JQuery Mobile is still beta software, and as such I have encountered bugs. That being said, the team is extremely responsive in addressing issues on GitHub. I think one of the big problems is simply quirks across various browsers on different platforms. I am certain that this will be ironed out over time. The applications also can look quirky in a visual sense - while I think the JQuery Mobile team have done a great job with their widgets and themes, it is still fairly distinct from native. How much this really matters to users is not clear, but it is something to be aware of.

3. Limited Capabilities vs Native:

   Obviously, JavaScript running in a browser does not have full access to many features of the device. A common example being the camera. However, tools like PhoneGap help greatly with many common issues. Indeed, I have started working on deploying versions of my app for iOS and Android with PhoneGap - using native Facebook bindings - and am quite impressed. I will be writing about my experiences with PhoneGap and native bindings in future posts.

Conclusion

To sum it up, I believe that JQuery Mobile and HTML5 is a viable platform for mobile application development. However, it does not (yet) suit all classes of applications. For simple content display and data entry-type apps (as opposed to very rich multimedia/gaming applications) it can be a great force multiplier compared with native. I certainly am happy with how it has turned out for my app - I simply do not have the time to maintain a port of my strength tracker app for both Android and iOS.

Over the course of the next 1-2 years, as hardware gets faster and devices proliferate, I believe HTML5 (and JQuery Mobile, PhoneGap, etc) will be even more important technologies in the mobile app space.

Niall O'Higgins is an author and software developer. He wrote the O'Reilly book MongoDB and Python. He also develops Strider Open Source Continuous Deployment and offers full-stack consulting services at FrozenRidge.co.

Video: An Obvious Killer App for Tablets

After a decade or so of various failed or underwhelming attempts, it is now blatantly obvious that Apple kicked off the consumer tablet revolution with their launch of iPad in 2010. By getting the hardware, pricing, UI and application ecosystem right, they have managed to sell 15 million units in 2010 alone (April - December), bringing in $9.5 billion.

An obvious killer app for this kind of device is video. At the distance you hold a tablet it has the same apparent size as a massive TV screen. The easy-to-hold and carry form factor, the long battery life, the high quality screen and speakers - and apps like Hulu Plus, Netflix, ABC and CBS pretty much have the TV and movie situation covered, with more services and apps coming all the time, to both iOS and Android devices.

In the not-too-distant future, practically everyone will have a tablet, and everyone will want to watch video on them. Awesome!

1) NVIDIA Tegra2 Chip Performance Surprises: Not What They Claim To Be

You've probably noticed the recent explosion in Android handsets and tablets powered by the NVIDIA Tegra 2 chip. It offers extremely impressive performance with a dual core ARM Cortex-A90 clocked at 1Ghz, and powers the latest devices including the Motorola Xoom, Atrix, Bionic and Samsung Galaxy Tab 10.1 along with a host of others just-released or near-release.

Tegra 2's Dirty Little Secret
What you may not be aware of amidst all the marketing is how poorly these Tegra 2 chips decode video. Tegra 2 is not capable of playing just any old video format. While technically it supports H.264 at 720p and 1080p, it specifically only supports the "Baseline" profile which means two reference frames and no B frames.

This means you must take your existing HD video files and re-encode them into a special format using a program like handbrake. According to Anandtech, that puts a 2 hour movie at around 8 GB - too big to fit as a single file on a typical microSD card formatted with FAT32.

Additionally, with those kinds of space requirements, streaming 1080p HD video for viewing on your device quickly becomes extremely bandwidth intensive (~10mbps). Almost certainly too high for most consumer Internet connections - according to DSL reports average Internet connection speed in USA is 4.7Mbps.

In other words, your brand spanking new, top-of-the-line 2011 dual core 1Ghz tablet cannot simply play any 720p/1080p HD video file you throw at it. Unlike a cheap PC or media center, in order to watch video on your shiny new Tegra 2-based tablet you:

• Almost certainly will have to re-encode your video specially for the device.
• Need a ton of storage space, approx. 8G per movie, possibly having the video split across multiple files.
• If streaming true HD video in 1080p baseline profile, need a very fast (~10mbps) Internet connection. (FWIW BBC iPlayer HD streams are 720p @ 3.2 MBPS. These HD streams are not available on iPad since that only supports baseline too!)

Ouch! Rumour suggests this is one of the reasons why HTPC (Home Theater PC) manufacturer Boxee ditched the Tegra 2 platform for the Intel Atom.

2) Samsung's Hummingbird CPU: DivX Certification

An interesting tidbit about Samsung's Android devices: Many of them - including 7" Galaxy Tab and the Galaxy S phone - are DivX certified! What does this mean? It means they can play pretty much any old HD video file (at least 720p high profile) you throw at them without the friction of painful, space-wasting conversion processes!

What about the soon-to-be-released Galaxy Tab 10.1? We don't know exactly, however all information so far suggests it will be powered by the same NVIDIA Tegra 2 chip. Unless Samsung does something custom, this device will have the same video limitations as the Motorola Xoom.

However, there is speculation that the other tablets Samsung is planning - in particular an 8.9" device - may use the next generation Samsung CPU named Exynos. This dual-core CPU could well have the same DivX certification as the Hummingbird devices, offering these devices superior video playback capabilities compared to Tegra 2.

This may mean that consumers interested in good video playback support should hold off on the otherwise very promising Galaxy Tab 10.1 and wait for an Exynos-powered device instead.

3) Tegra 2 Honeycomb Exclusivity: But Won't Last Long

Android 3.0 AKA Honeycomb is the first tablet-optimized version of the OS. If you want to be able to truly take advantage of the extra screen real estate afforded by the tablet form-factor, you will want a device with Honeycomb.

The first round of Android 3.0 tablets are all powered by Tegra 2. According to the SVP of Cellular Products at Qualcomm the reason for this is that Google partnered with Motorola on the initial launch devices. For whatever reason, Motorola chose Tegra. However, Honeycomb will soon be ported to and running on processors from other vendors.

As soon as Google open-sources Honeycomb, we should see a flood of Android 3.0 tablets from vendors like Acer, Asus, HTC, Samsung and others with much better video playback support - which means much better value for consumers!

Niall O'Higgins is an author and software developer. He wrote the O'Reilly book MongoDB and Python. He also develops Strider Open Source Continuous Deployment and offers full-stack consulting services at FrozenRidge.co.