ENTRIES TAGGED "mobile"

5 ways to improve battery life in your app

Tips and tricks to squeeze the most out of your mobile UI

mobile_html5 Editor’s Note: Mobile HTML5 is a book by front-end engineer and frequent speaker Estelle Weyl. It is packed with hands-on examples to make you a stronger web developer–including best practices for SVG, Canvas, and CSS3 tailored to fit mobile devices. In the excerpt below, Estelle walks you through five easy things you can do to improve battery life in your mobile web apps. As throughout the book, the tips she provides come from her own real-life experience with these technologies.

Unlike desktop computers that are tethered to the wall at all times, and even laptop computers that are generally used by stationary users, mobile users do not recharge their devices throughout the day. Mobile users expect their devices to last, at a minimum, 24 hours between recharging.

Your users do realize that calls and GPS usage consume battery power. However, if they think they’re just using their browser to surf the Web, they don’t consider that different websites will drain their battery faster than other sites. It is our job, as developers, to manage the power consumption of our code.

You have likely noticed that CPU usage drains the battery on your laptop when unplugged. CPU usage drains the battery on mobile devices just as effectively. Anything that makes your laptop churn, warm up, or turns your computer’s fan on will also drain the battery of mobile devices (if they’re not plugged in). Code defensively: expect that your mobile device users are not plugged in.

To manage the energy consumption of our code, we need to manage CPU usage. Avoid reflows. Minimize both size and activity of your JavaScript. Don’t continuously reawaken the radio with unnecessary AJAX calls. Always use CSS, rather than JavaScript, for animations. And even though the marketing teams of devices that support WebGL insist that their devices are optimized, don’t serve WebGL to mobile devices. At least, not yet. WebGL battery performance is improving.

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Talking to Chromecast from iOS

Part One: Easily find Chromecast devices on your local network

Now that Google has opened up the Chromecast API for anyone to play with, it’s possibile to create iOS applications that can leverage the $35 device as a way to display to HDMI devices wirelessly. In this series of tutorials, we’ll go over the API, starting with configuring your project to use the framework, and finding devices out on your local network to play with.

Let’s assume you’ve set up a Chromecast device attached to an HDMI TV and have it configured for your local network. Now it’s time to get an App set up to use it. We’ll use the iPhone Simulator in these examples, since it can talk to Chromecast devices just like a physical device, as long as the Mac you are developing on is on the same LAN as the Chromecast dongle.

Begin by creating a project, as usual. For this example, I used a single-view Storyboarded app. I set up an UITableView inside the default UIView, hooking it’s datasource and delegate to the default view controller the wizard had created. Next, I went to the Google Google Cast API page and downloaded the iOS framework, then used the “Add Files…” project option to add the framework to the project, copying in the files.

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Upward Mobility: Your phone is your robot’s best friend

Rosie the Robot may feel more comfortable talking to Siri than to you

Recently, Glenn Martin wrote an article describing how robotics in moving out of the factory and into the house. And while Glenn restricted himself mainly to the type of robots that pop into your head when someone says the word (either the anthropomorphic variety or the industrial flavor), the reality is that there are a lot of robots already in the hands of consumers, although it might take a moment to recognize them as such.

I’m speaking of drones, and especially quadcopters, which are proliferating at an enormous rate, and are being used to do everything from documenting a cool skateboard move to creating a breathtaking overflight of a horrific disaster site.

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Upward mobility: TVs are the new mobile

Mobile developers to gain a new set of platforms for their apps

photo: EricaJoy http://en.wikipedia.org/wiki/File:Chromecast_dongle.jpg One of the perennial technologies that regularly appears at the Consumer Electronics Show is the smart TV set, but they never seem to gain the kind of traction that the manufacturers hope that they will. This may finally be coming to a end, however, as a new generation of smart TVs are poised to enter the market. Even Apple is finally supposed to release their own products in this space this year. And when these hyper-aware TV sets enter the Internet of Things, they are likely to do it running mobile operating systems.

The reasons for this are several. From a purely economic standpoint, the margins on televisions don’t really afford room to pay for a full-blown desktop operating system license, nor the hardware required to support a rich desktop environment. It’s also unclear that anyone would want to run Microsoft Word or other general types of software on their TV. While a free operating system such as a desktop Linux OS might fit the bill, especially since it is famous for being able to run on a meager amount of hardware, it is equally unclear if it will be able to run the software that manufacturers and users are going to want to see on a TV.

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The Altar of Shiny

Web design trends often carry hefty performance costs

Web and mobile users continue to expect faster sites and apps–especially when it comes to mobile–and this year I’d like to see people who work on the web spend more time focusing on performance as a user experience priority instead of chasing trends.

I recently ran across this article in Forbes, which lists a number of web design goals/trends that Steve Cooper is eyeing for a site redesign of online magazine Hitched. My intention is not to pick on Hitched or Cooper per se, but the list is a molotov cocktail of potential performance woes:

  • Continuous scrolling
  • Responsive design
  • Parallax sites

You can use most of those techniques without creating performance nightmares, but it is unfortunately rare. I feel like I’m living in an alternate reality where I’m hearing that users want simpler, faster sites, and yet the trends in web design are marching in the opposite direction.

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Upward Mobility: Predictions for 2014

All predictions are for entertainment purposes only!

It is a generally accepted requirement that all technology pundits attempt a yearly prognostication of the coming 12 months. Having consulted my crystal ball, scryed the entrails of a falcon, and completed a 3 day fasting ritual in a sweat lodge set up inside a Best Buy, I will now tempt the Gods of Hubris and make my guesses for the year in mobile.

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Update Mobility: The Year in Mobile

Plus ça change, plus c'est la même chose.

As the end of December approaches, it’s time to take a look at the year that was. In a lot of ways, 2013 was a status quo year for mobile, with nothing earthshaking to report, just a steady progression of what already is getting more, um, is-y?

We started the year with Apple on top in the tablet space, Android on top in the handset space, and that’s how we ended the year. Microsoft appears to have abandoned the handset space after a decade of attempts to take market-share, and made their move on the tablet space instead with the Surface. In spite of expensive choreographer board room commercials, the Surface didn’t make a huge dent in Apple’s iPad dominance. But Microsoft did better than Blackberry, whose frantic flailing in the market has come to represent nothing so much as a fish out of water.

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Upward Mobility: 3 Unanswered Questions About Mobile Technology

Here's a couple of Big Questions that may take generations to answer

I spend a lot of time on this blog focused on the very short term issues regarding mobile. Is Apple better than Android. Will Blackberry survive? What’s the best strategy in Candy Crush? But sometimes you need to pull up to 30,000 feet and look at some of the bigger questions, such as:

What are the real long-term health effects of cell-phones? Wearable mobile technology has only been around for a few decades, and in true widespread use for less than 10. Are there health risks to having an RF transmitter that close to your head for long periods of time? More importantly, are there effects on offspring to carrying a two watt transmitter in close proximity to your reproductive organs for 18 hours a day? This is even more significant for women, where the effect would be cumulative from birth, since eggs are carried for a woman’s entire lifetime. Short term studies have shown mixed results, but lifetime exposure hazards are hard to gauge when the technology itself is so new. We really didn’t understand the cost to society of lead in our gasoline until half-a-century after its introduction. A decade of data on cell phones is unlikely to hold all the answers to the scope of the potential problems.

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Upward Mobility: The Forgotten Mobile Platforms

They may not be as pretty, but low cost embedded computing is a big thing

When thinking about the mobile development space, it’s easy to make the mistake of restricting it to smartphones. Apple, Google, Microsoft, and the stragglers dominate the news, and seeing someone typing away at a handset has become ubiquitous. But below the surface, there’s another set of mobile platforms that tend to get ignored, outside the DIY community, but are revolutionizing the world in their own way.

Traditionally, embedded computing was restricted to high-volume commercial applications (e.g., smart refrigerators and automobile control systems.) The intrepid hackers dabbled, but the amount of hardware knowledge required to get a CPU, memory and I/O logic onto a breadboard prevented any but the most experienced from implementing their own low-power embedded creations.

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Upwardly Mobile: IPv6 For Mobile?

Brace yourself: Address exhaustion is coming

IPv6 is the global warming of the computer industry, an impending disaster that most folks don’t seem to be taking as seriously as they should be. We’re well into the exhaustion phase of the IPv4 address space, but most ISPs are still dragging their heels on supplying the wider protocol to the end user.

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