What all mobile web devs should know about PhoneGap

If you already building or looking into getting started with mobile web applications you should understand the basics of PhoneGap. The name ‘PhoneGap’ is widely recognized, and perhaps more widely misunderstood.

The nudge to write this article was born out of conversations where we stumbled across concrete limitations to modern responsive JavaScript libraries such as bootstrap and jQuery. Limitations that cannot be overcome by adding more brilliant functionality because some JavaScript capabilities simply do not exist within the browser today. Furthermore, other requirements were imposed by political realities, timeframes and expectations.

That’s where PhoneGap steps in. 

So what, tell me what PhoneGap does?

PhoneGap is owned by Adobe and it has an open source top-level Apache Foundation sister project called Cordova. I won’t bore you with its long and twisted history, you can read about it here if you want.

The bottom line is PhoneGap allows you to develop JavaScript mobile applications that have access to certain aspects of the native device such as writing data to a filesystem. Your web application is wrapped within a native mobile application container that gives you JavaScript access to native operating system capabilities beyond what the browser itself is capable of doing!

By native I mean iOS Objective C, Android Java, WindowsPhone, Windows 8, Blackberry 10, Amazon Fire OS and Tizen. Your JavaScript applications runs in a chrome-less browser that gives you special hooks to the operating system. You can also submit PhoneGap applications to the AppStore, Google Play and others.

Who uses this stuff, well you may be using a PhoneGap app from one of these online stores and not even know it. To mention a few: Southwest Airlines and many others.

What limitations can PhoneGap address that responsive libraries don’t?

If your requirements call for all or most of the following items, then PhoneGap is the correct choice for your project today. That may change as HTML5 continues to rapidly grow, but for now I’m sticking with the following bullet points. Stick with me and read through all of these before starting to throw out counter arguments.

JavaScript skillz. If you are an existing JavaScript shop, then PhoneGap leverages your existing JavaScript skills to access capabilities beyond current browser functionality without the need to have an in-depth understanding of Objective C or Java.

Sure, it’s easy to say you can hire expert contractors to develop iOS and Android applications, along with UX designers and testers. But, if your budget doesn’t include the capital costs for these folks and all you have is JavaScript ninjas on staff then the choice is easy.

Or, maybe you have genius-level developers that could easily and quickly spin up on all your need to know on ObjectiveC and Java Android. If this isn’t the case, and your timeframes and budgets don’t allow for this then you’ll need a fallback plan such as PhoneGap.

Access to camera.  Yes, you can currently access the camera on some web browsers today. However, the support on mobile browsers is still inconsistent, limited or non-existent. On the other hand, native device OS’s are expected to have access to cameras If they didn’t it would be considered a serious oversight. PhoneGap provides cross-platform mobile device access to the camera.

Read/write access to SD Card. Just to reiterate, this is both read and write access to a local storage device. Certainly there is a FileReader API in plain old JavaScript, but as far as I know there isn’t a FileWriter or its equivalent yet. If you need the write access to go along with read capabilities then you should be looking at PhoneGap.

[Correction Jan. 27, 2014] I mis-wrote. The FileWriter API exists however it has limited supported across browsers: http://caniuse.com/#search=filewriter. And, examples of it’s use can be found here.

AppStore or Google Play. If you have a requirement to submit your application to the app store then PhoneGap will help you get there. There is no way today for submitting a stand-alone web application for acceptance on AppStore or Google Play. Period. Some will argue that the need for using these online application stores is going away, but that’s a non-issue if you have been directed to meet this requirement a.s.a.p. and your job depends on it. If that’s the case, then PhoneGap will be your friend.

Is there anything else I should know?

Yes…First, PhoneGap is not perfect, but then again few software projects are perfect. You will need to install and know a few things about the native IDEs you want to support. If you want to deploy Android you’ll need to install Eclipse or IntelliJ. For iOS you’ll need to install XCode. Etc. You still have to compile a native project or you can try your hand at Adobe’s PhoneGap Build, which is a cloud based build system for PhoneGap.

It is confusing that there are two projects that share a common/similar code base: PhoneGap and Cordova. Also, Cordova’s documentation has typically been more up to date that Adobe’s. If you do your research you’ll find various performance complaints and bug issues (like I just said are there any software projects that don’t have these??).  Yet, overall it’s a great starting point if you have the needs listed above, and it’s much better than trying to start from scratch given today’s dramatically shortened delivery expectations.

You can absolutely still use bootstrap, jQuery and other JavaScript libraries within PhoneGap. There are caveats, of course, related to application life-cycle issue, navigation as well as App Store and Google Play user interface acceptance guidelines.

If you want to add functionality to PhoneGap because you find some critical thing is missing that you need for your project, the good news is you can develop a custom plug-in.

Last, I should mention Titanium Studio. It also lets you leverage JavaScript skills, with the primary difference being that it converts JavaScript into native byte code rather than just displaying it in a chrome-less view.  Plus it’s comes with its own IDE and MVC Framework.  I’ve never used Titanium so I can’t judge it, however I know people who do use it successfully and love it. It’s one more thing to consider that you should be aware of.

References

Cordova Documentation

PhoneGap Documentation

PhoneGap Platform Support

The Art of Internet Connectivity

Everyone’s internet connectivity experience is unique and it can vary from minute to minute. Most internet users can sense slowdowns, and everyone can identify when a connection fails. Web developers absolutely rely on a web connection to build web pages. So, when our internet connection goes down our productivity comes to a halt.

I’ve lost count of the number of times I’ve reported to various tech support organizations that I wasn’t able to reach a particular website or web service and was told by the tech: “I was able to reach it just fine.” This happened again today when I called my DSL provider to inform them our internet service went down completely and then was degraded to 1/10 of what we were paying for (e.g. ~1.12 Mbps on a 12 Mbps service). They told me that the line was stable. Although I’m not real sure what stable means. Then the speed gradually increased back up to normal of over the next hour and a half. This has happened about a half dozen times over the last three months. 

As a web developer, you load web pages up to several hundred times per day. I almost always have monitoring tools hooked up that give the exact time to download a page and its associated elements. So, I have a good idea of when the internet is performing well, and when it isn’t.  Because of this I’ve become sensitized to small, millisecond changes in download times.

I also gained extensive knowledge of internet connections when working on high availability systems with up to five-nines uptime. We deployed systems that monitored web traffic all over the U.S. 24×7. I was amazed to see that internet traffic was very much like our roadways. Sometimes traffic is moving fast, other times it’s slow in spots, and sometimes it’s completely stopped or even re-routed.

In many cases, a modem (or router, as I’m using the terms interchangeably) simply locked up. This is quite common as these devices often run a small linux-based operating system that can occasionally flake out. I can say with certainty in the cases where my DSL modem/wireless router didn’t die, and there was no internet connection, then in 9 out of 10 of these cases it was a problem upstream with the carrier.

Guidelines. So, here are some guidelines for helping you narrow down where the problem might be:

– Check the modem connectivity lights. Usually if a modem is connected to the internet, the connectivity light will be a steady or flickering green. Red  or no connectivity light almost always means no connection. It should be a matter of reflex to simply restart the modem and see if that fixes the problem.

– If the internet connectivity light doesn’t come back after restarting the modem, then call tech support.

– On rare occasions (1 out of 10), restarting the server plus the modem restored connectivity.

– Still no service? You can go get a cup of coffee then come back later and recheck.

– Or, if the internet connection light is green, try blowing away the browser cache and try to reload? Sometimes old versions of pages can stick in the cache.

– Can you load any other websites? If you can, then your particular server or service is most likely down.

– Can you ping the server? (for servers that allow ping). Determines if the server has basic connectivity.

– Can you run a tracert? Let’s you look at the connectivity between you and the remote server.

– Document the problems so you have a record for future reference.

– If you need continuous monitoring with alert thresholds, then look into evaluating continuous monitoring tools such as Paessler.

– If you know how to get the basic troubleshooting out of the way, or if you’ve already done it, then insist on escalation when you call tech support. You need to get back to coding as fast as possible.

OSCON 2012 Presentation – Mastering HTML5 Geolocation

Want a fast and fun learning experience on adding location to your web apps? I’ll be sharing practical tips on how to shave days or weeks off your learning curve. The session will cover the HTML5 Geolocation API, its benefits, how it works and what doesn’t work using real-world examples covering both desktop and mobile. If you are planning on attending OSCON 2012 stop by my session and say “hi”. My session is Location, Location, Location – Mastering HTML5 Geolocation, 1:40pm Thursday, July 19th in Portland 251.

 

7 Critical Things to Know When Building Any Mobile App

This blog post builds on concepts proposed in an earlier post about not all mobile apps being created equally. If you are a developer who is in the process of migrating to mobile this post is for you. It’s intended to raise awareness of important items to consider in your requirements. My goal is to help you identify some of the major gotchas early on in the development process and improve your chances for success.

There are many more details to learn on the topics I’ve described below. The good news is that in the last few years the amount of deeply helpful documentation has expanded considerably. Where possible I’ve tried to include links related to each topic.

Touch-based Workflows. Recent research has shown that people use their smartphones more often than web apps, and they spend roughly 80% of their time on social media and games. Because of this and the fact that smartphones today are touch driven and not mouse driven, you have to take that into account in your user interface design. Touch implies many things including gestures and multi-touch. You can toss your old conceptions of user interface design based on desktops and tablets, and check out Android’s recommendations as well as Apple’s. My strong recommendation is to hire a UX designer to help you through building a user interface.

Mutliple form factors come with various screen sizes and densities. Long gone are the days of building for just three main browser types. Now you have to take into consideration iPhones, iPads, tablets, numerous different style androids as well as desktop and laptops. Android defines the following screen sizes and, as you can see, this is quite varied and smaller than a typical laptop or desktop. Those typically run 1024 x 768 or greater.

  • xlarge screens are at least 960dp x 720dp
  • large screens are at least 640dp x 480dp
  • normal screens are at least 470dp x 320dp
  • small screens are at least 426dp x 320dp

This is important to know because an app that looks good on an iPad may not look good, or display correctly, on the four inch display of a Motorola Atrix at 960 x 540. A button that looks correctly sized on one smartphone may look too big on another. A whopping 84% of all Android screens are what Android defines as normal size (>=  470dp x 320dp) and between either medium dpi (~160dpi) or high dpi (~240dpi). But, you still have to take into consideration other densities. I also recommend taking a look at new HTML5 browser-based technologies to help with addressing this problem, such as CSS media queries.

Inconsistent Internet. It’s a best practice to check if internet connections exist and gracefully handle HTTP requests when the internet is down, as I blogged about here.  Depending on your application and needs, you should also monitor whether or not a wireless connection can be made and then allow the application to switch to wireless where possible. Wireless also has the advantage of using less battery power.

Slower Connections. And, on a related note, you can’t always depend on 4G connections having consistent maximum download speeds. Over the course of a user session, the connection speed will vary widely and you should plan for that. I’ve been trying to find some stats on mobile internet quality world-wide, if they are out there they are hard to find. But, we’ve all experience spotty mobile internet coverage. Take this into account if you are transferring large amounts of data between your servers and your app. You should also consider detecting when the user is in an area of greater bandwidth and use that to download more data less often. Use loosely coupled and event driven architectures. Test app load times on various devices and around town and away from your office.

Less CPU Horsepower. While the latest generation of four core phones are certainly the most powerful phones yet. In general, applications and web pages will run slower on phones than they do on your development machine running a desktop browser. Take older generation phones into account because they are usually significantly slower than the newer phones. There are a few workarounds in HTML5 to help with this, in that done correctly they can offload rendering to the hardware. In native applications be aware of memory leaks because, remember, more memory usage means less battery life and applications that can run slower over time.

Support across multiple operating system versions. Remember on Android that the vast majority of users are still running v2.2 – v2.3.7 even though v4.x is currently shipping. You’ll have to do some research on your target market and find out what versions and type of phones they are using. You can’t support everything, but you can make educated guesses. Apple, on the other hand, has a significantly more limited selection of phones and tablets that you have to support, and they do a great job helping you support those.

There are some solutions that help with building cross-platform mobile apps, to go into more detail will take another blog post. Here’s a few: Adobe Flex, PhoneGap and Titanium. Keep in mind that the future of Flex, as a development platform, is being called into question after Adobe open sourced everything but the browser and desktop runtimes to the Apache Foundation. PhoneGap and Titanium offer what is now being called “hybrid” solutions where you can build an application in JavaScript, for example, and then compile that code for native deployments on Android and iOS.

Battery Life. Ah, battery life is last but certainly not least. Be aware of how battery intensive your application is and try to minimize battery consumption as much as possible. The Android online docs have a number of highly information articles on this subject. Smaller app footprint in memory means less battery consumption. Heavy CPU usage means more battery usage. Minimize GPS usage through smart algorithms to help preserve battery life.  Switch to 802.11 wireless connections where possible, since this requires less battery power than 3G and significantly less power than 4G.

So, there you go. I hope these suggestions help. If you have more suggestions based on your own experience please post a comment!

References:

Android Gestures

Android Optimize Battery Life

Android Screen Sizes and Densities

CSS media queries

Android UI Design

Android Model for Best GPS Performance

iOS User Experience

HTML5 Hardware Acceleration

Event-based Architectures for Adobe Flex

What do you read for technical news?

It was just a few years ago that I regularly scanned a list of mainstream developer and IT rags on a weekly basis: ComputerWorld, Visual Studio Magazine, SD Times, JDJ, and the list goes. Then one day early last year the thought hit me and I was a bit stunned to realize that I’d stopped reading online magazines. The vast majority of my technical info was now coming from blogs, online help docs and dizzying amount of internet searches. So, what happened? I have some theories that I’ve been thinking over the last year, but I can’t really nail down anything for certain. So, it’s most likely a combination of these five concepts below.

Rapid Change. My first thought is that technology has been changing so rapidly that simply digesting the changes and understanding them takes a huge chunk of time. Huge. I’ve blogged about this a number of times. This trend cuts across the entire tech industry. The upside is that innovation happens overnight and fixes as well as new features come out quickly. The downside is it’s harder for everyone to stay on top of all the changes across updates to features, libraries, SDKs, smartphone operating systems and browsers.

Super busy. My second thought is:  in addition to staying on top the über release cycle of web and mobile technologies, I’ve been so busy with project work that I simply had to narrow the scope of what I was reading. It’s a balancing act and there’s only so much time in the day. Superfluous information seemed to just slow me down, or worse it felt like a distraction from the day’s objectives. And in today’s online environment there is such a huge flow of information. So, there has to be a way or mechanism for focusing and filtering the fire hose of inbound data.

Irrelevant Info. My third thought is that every time I try to go back and read mainstream rags that I find myself sifting through a bunch of stuff that isn’t relevant to my immediate or near-term needs. Like I mentioned above, a good portion of it often seemed to be superfluous. Don’t get me wrong: online magazines offer well written and well thought out information. But, I felt the extra information, or perhaps even information overload in some cases, slowed me down. If it takes time to sift through article after article looking for a specific topic, my inclination is to go back out to a search engine and narrow down my search parameters.

Online Search Engines. Search engines have done an excellent job of (rapidly) indexing online technical content. I don’t need to mention them by name because you know all the players. At work we’ve often joked about a pattern we call “coding by search engine.” The pattern goes something like this:  copy a class name or error message, paste it into the search bar and then skim through the results. If you have to go more than one page deep in the search results then stop and redo the search. Mostly gone are the days of sifting through reams of paper documentation or digging around in some esoteric corner of a vendors website. I don’t think most customers will stand for that anymore. I think more information is instantaneously available at our fingertips now than any other time in history. It is astonishing, really.

Forums. My final thought is the voice of the developer community has never been more important. Online forums, such as Stack Overflow, have become to be perceived as definitive sources on technical questions of all kinds and about all different sorts of programming languages. I’ve been in many conversations where, right or wrong, someone interjected with a comment about something learned on Stack Overflow, or similar sites. These sites are well indexed by search engines, the community can vote answers up or down, and many brilliant and knowledgeable players contribute their knowledge. These are excellent, speed-of-light resources that are freely available.

So, there you have it. This is my two cents of what I’m reading these days and why I think I changed what I read. Leave a comment or email me about how you get your technical info injection. I’m really curious to hear your experience.

* Clip art courtesy of Microsoft Office 2007.

The Largest Conference For Mapping and Geospatial Developers – Esri DevSummit 2012

I’ll be presenting at the Esri DevSummit next week so if you are attending please swing by my sessions and say “hi”. If you aren’t familiar with Esri or the conference, about 1400 developers and other technical experts converge on Palm Springs, California every Spring to learn all things technical about building commercial and enterprise geographic information systems. There will be everything from introductory Dojo workshops to deep dives into the heart of our APIs.

If you’re around here’s my schedule. I’d be very interested to hear about what you are working on:

Monday,  March 26

Getting Started with the ArcGIS Web APIs – 8:30am – 11:45am, Pasadena Room. I’ll be presenting the portion related to our ArcGIS API for JavaScript.

Gettings Started with Smartphone and Tablet ArcGIS Runtime SDKs – 1:15pm – 4:45pm, Pasadena Room. In this session, I’ll be presenting on our ArcGIS Runtime SDK for Android.

Wednesday, March 28

Flex the World – 10:30am, Demo Theater 2. I’ll be presenting with my esteemed colleague Sajit Thomas on Apache Flex.