Posts Tagged ‘native’

Where Part 1 focused on non-GPS enabled devices, Part 2 is totally focused on mobile web geolocation. The great news is that the usage of HTML5 location services along-side the fact that there is a GPS chipset in most, if not all, modern smartphones and tablets dramatically improves the chances of getting an accurate location. And, besides that fact — mobile geolocation is simply a lot of fun to work with.

I also want to point out that there are an increasing number of really good blog posts covering the topic of “how to use” the API that look at the nitty-gritty of how the code works. This post is different in that I’ve tried to focus on “how to build successful applications” with the API, and how to get the most out of the API so that you can successfully implement your unique requirements.

What’s different about desktop vs. mobile HTML5 Geolocation? With mobile you can access the GPS if it’s available. It’s important to note that in order to access a device GPS you have to set the optional enableHighAccuracy property in your code. Contrary to what is shown in some samples on the internet, you can use this property with both the getCurrentPosition() and watchPosition() functions.

//One time snapshot
navigator.geolocation.getCurrentPosition(
     processGeolocation,
     // Optional settings below
     geolocationError,
     {
         timeout: 0,
         enableHighAccuracy: true,
         maximumAge: Infinity
     }
);

//Tracking users position
watchId = navigator.geolocation.watchPosition(
     processGeolocation,
     // Optional settings below
     geolocationError,
     {
         timeout: 0,
         enableHighAccuracy: true,
         maximumAge: Infinity
     }
);

How accurate is it??? This is the million dollar question, right? When using enableHighAccuracy() on a phone where all the appropriate permissions have been selected and granted, I’ve typically seen accuracy readings as low as 3 meters (~10 feet) that were obtained within 10 – 30 seconds of kicking off the geolocation functionality. I’d consider that excellent for most consumer and retail applications. You should be aware that like any location-based functionality you will get spurious (abnormal) results that fall way outside the norm, and sometimes these results are wildly wrong.

I’ve seen claims that using the enableHighAccuracy() property slows down the phones ability to deliver a location. I’m going to argue that those claims are misleading. It is true that the GPS, itself, can take a significant amount of time to warm up and start delivering high accuracy results. For an in-depth look at that topic see my post on the Six Most Common Use Cases for Android GPS. However, there are conditions where simply enabling the enableHighAccuracy() property doesn’t affect the speed in which you can get the initial result. More on these topics below.

What is the best way to try out various configuration scenarios? I’ve built an HTML5 Geolocation Testing tool that can be used in browser, or it can be repurposed to work in PhoneGap or Titanium. It is a jQuery-based mobile application that includes a map and settings view were you can adjust all the different properties and try out different configuration scenarios. It’s a work-in-progress so I welcome suggestions and pull requests.

 Why HTML5 Geolocation rather than native? Applications using HTML5 Geolocation typically have slightly different requirements than native GPS-based applications. Each platform has its advantages and disadvantages and it all comes down to your requirements, budget, timeframes and skill sets:

  • Ability to re-use existing JavaScript and HTML5 skills to build a high-accuracy mobile application.
  • Don’t have access to native platform developers or skillsets on Android, iPhone and/or Windows Phone.
  • Need a cross-platform stand-alone web app, or a web app that has been repurposed to work with PhoneGap or Titanium.
  • Quickly locate the user/consumer within a reasonable expectation of accuracy.
  • Typically it is a non-commercial, consumer grade application that does not have extremely high accuracy requirements (e.g. < 1 meter).

How fast can I get an initial location result? The answer is very fast, potentially within a few seconds, given the following scenarios:

  • If there was a cached GPS or Network location stored on the phone. The GPS location is, of course, from the GPS chipset. The Network location comes from your wireless carrier and is dependent on your phone and their capabilities.
  • How the timeout and maximumAge properties are set. If you set timeout = 0 and maximumAge = Infinity it will force the application to grab any cached location, if one is available. Other settings may result in delays.
  • If the phone or tablet has decent internet connectivity and Wifi enabled.
  • If the device is in an urban area with many wifi nodes broadcasting their SSIDs nearby.
  • The device has a clear and uninterrupted view of the sky. GPS’s listen for a very weak signal from multiple satellites. These signals can be partially or completely blocked by buildings, thick foliage, vehicle roofs, etc.

 How accurate is the initial location result? Hah, you might have guessed I’d say that it depends.  When you first kick off a geolocation request, accuracy does depend on a number of different factors that are mentioned above. And it’s safe to say that, in the vast majority of cases, the first location is not the most accurate and typically not the most dependable. If you want the fastest, most accurate location possible then you will most likely need to either do multiple snapshots, or use watchLocation until your desired level of accuracy is met. It’s important to note because I’ve been asked about this many times, you cannot expect the GPS, itself, to have enough time to lock onto a satellite and deliver a fast, accurate initial location. It may take dozens of seconds or even minutes. Yep, it’s true. Factors that affect initial location accuracy include:

  • Cached locations – how recently the user accessed location functionality. For example, applications like Facebook typically grab a location when you open the app. So frequent users of social media are more likely to have a fresh, cached location that non-social media users. If you are targeting business travelers, the cached location might the last city before they got on a plane. Or, it could be your home neighborhood and not where you work or go to games.
  • Wifi turned “on”. If the Wifi is turned on then the device can access the location service and there is a much greater chance that the initial result is fairly accurate. If you didn’t have a chance to read Part 1, when the Wifi is on your browser gathers local Wifi node information from your Wifi card, and it can use that information in a location service provider request over the internet to try and triangulate your position. Typically this means your initial location can be within a block or two of the actual position. Also, it is possible if Wifi is turned on that you can get a significantly more accurate initial location than if you were using GPS by itself with no Wifi or internet.
  • Internet connectivity strength. If you have a poor internet connection and no Wifi, then the browser’s requests to the location service can be delayed, blocked or even interrupted.
  • No VPN. Take note commercial application developers: as mentioned in Part 1, if VPN software is in use it can wildly affect accuracy and even place you in another State (or Country).

Can I use HTML5 Geolocation for mobile tracking? Yes, with caveats. Typically HTML5 tracking applications are built inside a native wrapper framework such as PhoneGap or Titanium. There are several immediate problems with stand-alone, browser-only HTML5 tracking applications. First, there is no built-in functionality to keep the screen from going to sleep. Second, when the screen goes to sleep the HTML5 Geolocation functionality also goes to sleep. Native-based tracking applications can work around these limitations and listen passively in the background when they are minimized. Third, you have little control over the GPS settings to help management battery consumption.

Can I use HTML5 Geolocation offline? Yes! If there is no cellular connection or Wifi available, then HTML5 Geolocation can still access cached locations and real-time GPS information. This is vastly different from what was discussed in Part 1 as related to applications targeted at laptops, desktops and tablets that may or may not have GPS. If a device does not have a built-in or externally available GPS then your offline application will not work.

Handling abnormal location results. Your application will occasionally encounter widely inaccurate results and you need to handle these gracefully for the best user experience possible. My recommendation is to check the timestamps and distance traveled between the current geolocation object and the previous one. If the distance or speed seems excessive then you’ll need to reject the result. In the reference section below is a link to more information on calculating the distance between two points containing latitude and longitude. As an example, see the attached screenshot with the spurious results indicated by red circles. Also note in the screenshot the accuracy level was 3 meters, so it’s important to understand that even at high accuracy levels you still need to very that each location meets your minimum requirements. This way your results will always look polished and professional to the end user.

Spurious results

What are some of the downsides of using HTML5 Geolocation versus native? The bottom line is that for simple location gathering and basic tracking HTML5 Geolocation is just fine. This should meet the requirements for most consumer applications. For anything more complex than that you should consider looking at going native.

  • It may not work on older phones and older browsers (depending on your definition of old). See below in the references section for a link to a fallback library to handle these situations.
  • HMTL5 Geolocation offers significantly less control over GPS settings. This can have an unacceptable impact on more complex applications.  Because of this, I also suggest that HTML5 Geolocation is not suitable for long-running tracking applications.
  • Battery life management. This is a direct result of bullet #2. It’s more challenging to manage battery life with HTML5 Geolocatoin if your requirements call for continuous use of the GPS.  Your control is very limited with respect to these two properties: timeout and maximumAge.
  • Cannot use it when the application is minimized. If your requirements calls for the ability to passively receive locations while in a minimized state then, as mentioned earlier, you will have to go native.
  • Very little control over how often you want location updates. You’ll need to do a bunch of custom coding to emulate what is already built into native application APIs. For example, the native Android API offers very detailed control over what type of geolocation data you can get access to, how you can access it and how often. Read more on that topic in my post on How Accurate is Android GPS Part 1 – Understanding Location Data and also take a look at Android’s LocationManager Class.

References

W3C Geolocation API Specification 

HTML5 Geolocation Test Tool

Mozilla – Using Geolocation

Calculating distance between two points.

Geolocation fallback library for older browsers

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Posted in Browsers, HTML5, Mobile | 19 Comments »

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

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Posted in Android, iPhone, Mobile, Windows Phone | No Comments »

In addition to the suggestions listed in Part 1, I forgot to mention one more tool. There is a lesser known browser that can be quite handy for debugging: Firefox mobile. This relatively unknown sibling of the full-blown desktop browser actually has a fairly nice, built in debugger. The one major caveat is that it doesn’t work as well as the native browser for HTML5, CSS3 and some JavaScript, but it may be just the tool you need for some quick debugging, on-the-fly. Besides it fits in your pocket along with your other mobile apps, and you don’t need Logcat.

Step 1 – place your finger in the middle of the screen and drag it to the left. Click the gears icon at the bottom right of the screen.

Step 2 – In the upper right hand corner of the next screen, click the bug icon

Step 3 – Scroll down the datagrid to view errors.

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Posted in Android, Browsers, JavaScript | No Comments »

Debugging HTTP Requests on Native Android Apps

If your native android app uses HTTP requests, then there is currently nothing built into Logcat that let’s you see HTTP connections. Just to clarify, you can see HTTP requests in Logcat when they come from the Android browser, but not when they come from a native app.

Like many of my blog posts, I’ve done a fair amount of searching before I try to re-invent the wheel. And, on this topic, I scoured the Logcat documentation, and I looked around for several days and found nada. Zip. Zero. The bottom line is I need a full-proof, gimmick free way to test HTTP connections that will work all the time.

Here’s the Solution. Load wireshark protocol analyzer on your machine, turn it on, and then run your app in the Android emulator. There are other protocol analyzers you can use, such as Charles, but I prefer wireshark.  If you aren’t a developer and you don’t have access to the source code, then you are probably out of luck.

Why does this work? This works every time and all the time because the emulator runs on your machine, and the protocol analyzer picks up any HTTP request coming from the emulator (or anywhere else on your machine for that matter). Period.

Tip #1. If you haven’t used wireshark before then when you turn it on, in the filter field apply either http.request or http.response to cut down on the noise you’ll pick up.

Tip #2. Yep, you can also use this methodology to debug apps running in the Android browser of the Emulator. Also, as a bonus, if you are using this methodology to debug browser apps, you can set the proxy settings on your phone (or browser) and point them to the IP address of the machine running Charles or Fiddler, for example. Note, this only works if your phone and proxy are on the same network, and if your wireless router also acts as a LAN router to allow HTTP connections between machines. If you don’t know how to set proxy settings for your browser just do a search on “proxy android.”

Here’s an example with http.request. The services shown in the image are publicly available:

Here’s an example with http.response:

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Posted in Android, wireshark | No Comments »

For some unknown reason, Google did not include a debugger in their native browser, at least for versions up to v2.3.x. I don’t have a phone that supports a version greater than that, yet, so I can’t speak about the latest releases. Unfortunately this can be a huge productivity killer. The good news is there is a solution – you can debug the native Android browser using what’s called the DDMS, or Dalvik Debug Monitor Server, and the ADB, or Android Debug Bridge. I can also tell you this works great.

Yes, it’s true that JavaScript development forces you to have an armada’s worth of tools, tricks, libraries, phones and browsers. This is just another hammer to place into your growing toolkit. Debugging via ADB was good news for me since I do native Android development and I already have the software installed when I installed the full Android SDK. If you don’t do native development then it’s a real pain.

But, if you want to do your best to deliver bug free apps, then your best bet is to install at least ADB. I believe, but I’m not 100% certain, that you can this without having to install Eclipse along with the entire Android SDK. Yes, I agree that installing the entire SDK would seem entirely ridiculous and complete overkill for mobile web development, especially if you are not using Eclipse as your primary IDE. I’m aware that in the past I’d seen a few stand-alone versions of this floating around for both Windows and Linux. I’m not even remotely certain about Mac’s. If you do know something about this, then I encourage you to please post a comment.

How to use ADB. My suggestion, once you’ve installed it, is to filter by the tag “console” if you are using Android v2.x and above.  Instructions on how to do filtering can be found in the ADB link below and scroll towards the very bottom of the page.

Caveat: You will have to install the Android USB device driver on your machine in order for ADB to work.  And, you will also have to have a USB cable that will connect your device to your dev machine. The drivers are different for every device. I’ve included a link to Google’s device drivers below. On a related note, for several of my Motorola Androids I had to go directly to the Motorola website to find a device driver that finally worked.

Another Possibility – Adobe Shadow! You should also be aware of a very cool development from Adobe called Shadow. As of today, I believe you can still download it for free from Adobe labs. I mention this last because, well…I haven’t tried it out. However, my good friend Kevin Hoyt, from Adobe, says it’s very, very promising. And, it’s supported on both Mac and Windows. As I write this I’m thinking that I really do need to download it and test drive it. If you have tried it, then post your thoughts…don’t by shy!

References:

Adobe Shadow + sneak peak video

Google’s ADB

Android Device Drivers

Google’s Guidelines for Web app developers

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Posted in Android, Browsers, JavaScript | No Comments »

Most smartphones users I know ditch apps pretty quickly if they don’t work or end up being clunky. So, if your company is considering offering mobile apps to your customers you should be aware of a few things.

Buy a Smartphone. If you don’t already have a smartphone then you should go out and buy one. Then download a number of apps that interest you and try them out and see what you like and what you don’t like. For example, if you do the shopping for your family you might consider trying out a bar code scanner app that lets you compare pricing. Some scanner apps may work faster than others. If you don’t own a smartphone then you won’t be able to understand what a good app is.

Likes and Dislikes. Pay close attention to what you like and don’t like about a particular app. Here are a few questions to take note of:

  • Was it easy to use?
  • Did it hang and/or crash?
  • Did it perform its tasks gracefully?
  • Did it do what you expected?
  • Was it visually appealing?

Become Tech Savvy. Become a bit more tech savvy about things that the phone is doing behind the scene. There are apps that do this for both Android and iPhone that help you monitor what’s going one. Things to look out for:

  • Apps that keep running even after you think you shut them off. These will run the battery down faster.
  • Apps that consume more and more memory over time. Using more memory equals more battery usage and shorter time between charges.
  • Apps that seem to slow your phone down when they run. These apps may be using more CPU than necessary resulting in greater battery usage.
  • Apps that connect to the internet frequently costing you extra data charges. There are apps that let you monitor how much data your phone uses and some apps can help pinpoint which apps use the most data.

Which Phones to Support? Understand what devices to support. If you are building an application for internal use, then you have an easier decision since you hopefully have some control over which devices are being used and how often their software gets updated. If you work in retail, your users may have Androids, Blackberries, iPhones, iPads, Kindle’s, Nook’s and possibly other tablets that get updated whenever and however the customer dictates. My advice is do some research and pick one that is used the most and work on that first.

Release Early and Iterate Often. Technology changes so quickly these days that if your app takes more than 3 – 6 months to build, then the technology will change underneath you. In other words, you might be releasing an application that doesn’t work perfectly with the latest phone operating systems or browsers that your customers are using. When that happens, it will cost you even more time and money to fix the problem and the problem will repeat itself. Be sure to take into account the speed at which technology will change once you begin your software development process.

Go Native, Go Web Browser, or Both? Last, it’s important to understand that there are two common types of mobile applications. Native apps are downloaded from an app store and installed directly on the phone, the other is a web app that runs in the phones web browser. My advice is to research and understand your target market. What do your competitors use? What do your customers prefer? What are the trends in your industry?

If you go with native apps, you’ll need to understand which phones to support and how often you will be updating the app. If you choose web apps you’ll need to know which browsers to support. Also take into consideration which skill sets your development team has and understand if they can tackle the project or if you need outside help.

Update, Update, Update. No matter what you decide, you can’t just deploy an app and think you’re done. If you want to keep your customers happy, you’re going to have to keep updating the app until the product line is discontinued or replaced. And, you have to update it often enough to stay on top of the latest technologies. New smartphone models are being released all the time and they all may have different screen sizes and screen resolutions. An app that looks good at one screen size may look horrible on a tablet or iPad. These things have to be accounted for. And, the smartphones operating system software may be updated three or more times per year offering new functionality and fixing bugs. If your customers download a broken app, or if they see the app that hasn’t been updated in a while and something stops working they may not be your customers for much longer. This is especially true for retail apps where customers make split second decisions whether to stay or walk away and try something else.

Conclusion. I hope you find this list useful and at least give you some ideas to think about before you dive head first into bringing a new mobile application into the world. It can be fun, be there is a lot of hard work involved. But, if you plan it right you’ll be successful and learn alot in the process!

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Posted in Android, Internet, iPhone, Mobile | 1 Comment »