Peter Foot : Windows Phone

Cross Platform NFC

Peter Foot — Fri, 24 May 2013 18:20:00 GMT

NFC support in Windows Phone provides an exciting new way to add interactivity to apps and games. This series of posts will look at the state of NFC across the Windows and Android platforms. There are a number of standard Tag types defined by the NDEF format, for the sake of simplicity we’ll ignore the fact that Android can read other tag types and just concentrate on NDEF as it provides the best interoperability. Representing Windows Phone 8 I’m using the Nokia Lumia 920 although the 820 Developer phone provides the same experience. Representing Windows 8/RT is the Asus VivoTab RT which is one of few tablets with NFC support built in. Representing Android is the Samsung Galaxy S3. Since I’m less familiar with Android there is a possibility that some of the functionality I have discovered is Samsung specific and not part of the core Android OS.

Sending

The first table here shows the formats for which sending is supported within the platform. I haven’t included app links as these are platform specific. I was disappointed to find that out of the box the Windows tablet has no capability to share items over NFC from the built in apps. The send behaviour on Android is very seamless – tap the device against another and if the current app can share the screen changes slightly and you tap to share the current item. On Windows Phone you have to go through a few layers of menu first before being prompted to tap a device.

	Windows Phone	Windows 8/RT	Android 4.1
Uri	Yes	Requires 3^rd Party App	Yes
Mime (vCard)	Yes	Requires 3^rd Party App	Yes
Text	No	No	No

Receiving

The platforms can receive over NFC so long as the device is not pin locked. The following list shows what types of data (or pre-written tags) you can read on these devices without any specific third-party apps running.

	Windows Phone	Windows 8/RT	Android 4.1
Uri	Yes	Yes	Yes
Mime (vCard)	Yes	Yes	Yes
Text	No	No	Yes

So from a very high level the three platforms support the basic tag types for Uris and Contacts across the board. Although Android has default behaviour when receiving a Text tag it just displays the text on screen – there is no functionality to do anything with the text. In a future investigation I’ll look into the tag types in more detail. The Uri tag for example is very powerful because you can register custom Uri schemes for your app so that a Uri tag could provide a deep link into your application. The systems maintain support for well-defined Uri schemas like http, tel and sms for example. There are additional platform specific ones on Windows Phone for launching items such as Wifi and Bluetooth Settings pages.

Launching PDF Documents

Peter Foot — Tue, 16 Apr 2013 10:12:00 GMT

In Windows Phone 8 the Windows.System.Launcher class allows you to open files with apps which are registered to handle them. On Windows Phone you have built in support for Office documents and audio and video formats. Lets say you want to open a PDF either remotely or downloaded by your app. There isn't a built-in PDF viewer but there are several available including free readers by both Microsoft and Adobe. If your user doesn't already have one installed there are some extra steps. The first thing that happens is that the user is prompted like so:-

If the user taps yes the phone will display a store search for apps which are associated with the file type:-

Not sure why Adobe Reader isn't in this list and why it looks like the last entry is a game :-) but at least the top couple of entries seem like they will do the job.

Prototyping with Infragistics Indigo

Peter Foot — Fri, 12 Apr 2013 11:41:00 GMT

I recently needed to create a prototype for a Windows Phone application and having recently discovered it I decided to use Indigo Studio to build it. The application is not particularly designed for Windows Phone however it has enough standard UI controls and customisations to make it easy to create phone mockups. They say a picture says a thousand words so why not have a look at a sample I created showing a few screens of an imaginary phone application.

http://indigo.infragistics.com/prototype/XX47K8P4

In posting that link I've just highlighted one of the great features - you can build a prototype and then share it (either on Infragistics servers or your own) via the web. The Silverlight magic then gives your clients a rich experience to understand the scope and user flow around the application. I intend to revisit this in a series of blog posts to discuss gotchas and tips for creating Windows Phone prototypes. Oh and one of the best features - it's free!

Working with .png Images

Peter Foot — Wed, 27 Feb 2013 13:30:00 GMT

In my previous post I discovered a limitation with using the Share... extension point in the Photos app. The good news is that from within your own app you can open .png files. For this you can use the PhotoChooserTask which has been available since Windows Phone 7. This presents the user with essentially the same UI as the Photos app and you can browse the Screeshots folder and select those .png files. The Completed event returns you a PhotoResult containing the raw stream and the filename which you can use to open the file. Because .png access is available this way it seems an odd decision that it is not supported from the Photos app itself. The moral of the story - provide multiple methods for your user to select files...

Photos Extra Share and .png

Peter Foot — Mon, 25 Feb 2013 23:32:00 GMT

On Windows Phone 8 it is possible to register your app with the Share... extension point on the photo viewer. This allows your app to receive an image file and process it whether that is sending it to an online service or manipulating it on the device. I found recently an odd quirk with the feature. I setup the extension following the MSDN documentation. I wanted to test on my captured screenshots on the device so I went into the screenshots folder, selected an image and tapped share. While a range of system extensions were shown my custom app was not. I later discovered that it works in other albums. The reason as it turns out is that all screenshots are captured as .png files and camera images are .jpg and for whatever reason photo extras are not enabled for .png files. I searched online and there was a forum discussion but it is still awaiting a formal confirmation from Microsoft that this is expected behaviour.

http://social.msdn.microsoft.com/Forums/en-US/wpdevelop/thread/095a3300-111e-46d8-968a-3af1036504b7

32feet.NET for Windows Phone

Peter Foot — Tue, 15 Jan 2013 20:34:00 GMT

With the recent announcement of Windows Embedded Handheld 8 it seems fitting to discuss something related to industrial and line-of-business applications which you can develop now on the Windows Phone platform.

I've released the first drop of 32feet.NET for Windows Phone 8 to our CodePlex site and NuGet. Because the programming model on Windows Phone (based on Windows Runtime StreamSockets) this is a separate package and doesn't follow the programming model of the main 32feet.NET release. Windows Phone 8 supports Bluetooth programming out-of-the-box it is not straight-forward as it is build around the Windows Runtime Peer networking APIs but is different to the Windows 8 implementation. The aim of the 32feet library for Windows Phone is to simplify common tasks. This initial release adds the following features:-

Strongly typed extension methods for ConnectAsync which accept service Guids or numerical port numbers
BluetoothDevicePicker which offers an easy way for a user to select a device. Equivalent to the SelectBluetoothDeviceDialog in the core 32feet library.
Common Bluetooth service Guids
Bluetooth Barcode scanner sample. This sample app connects to a Motorola CS3070 scanner and allows input of Barcodes to the device screen. It should also work with other Bluetooth serial based scanners.

This is just a first release and we will be continuing to develop the library as well as add further localisation and samples. For example to demonstrate connecting to applications running on the desktop (Sorry not Windows Store apps currently). Your feedback is valuable so please visit the CodePlex project site to provide feedback.

There is a NuGet package available for the Windows Phone flavour of 32feet.NET to allow you to easily add it to your projects:-

http://nuget.org/packages/32feet.NET.Phone

Persist Bluetooth Addresses on Windows Phone 8

Peter Foot — Tue, 04 Dec 2012 17:05:00 GMT

The Bluetooth API on Windows Phone 8 is based around some customisations to the Proximity APIs which are part of the Windows API introduced with Windows 8. When you "discover" devices you can retrieve a collection of device identifiers for paired devices. The first time you perform a task you will want to use this mechanism to select the appropriate device. However you may want your app to remember a specific device and try to connect again on subsequent attempts. In the old .NET world with 32feet.NET we have a constructor for BluetoothAddress which allows you to supply the address in a variety of string or numeric forms. In the Windows API the Windows.Networking.HostName type is used to represent a host name whether it is for a Bluetooth device or an IP address. Normally the read-only Type property will indicate the type of the host.

In order to store a Bluetooth address for later use you should save the RawName property which for Bluetooth devices is in the form "(11:22:33:44:55:66)". The dotted hex notation is fairly common but notice the address is wrapped in brackets. Now to restore this address in a HostName instance you can later use to open a socket you can use:-

HostName storedHostName = new HostName(storedRawName);

You'll notice that this sets the host name and correctly sets the Type property to Bluetooth.

iCalendar Files on Windows Phone 8

Peter Foot — Fri, 02 Nov 2012 18:30:00 GMT

iCalendar files are based on the set of data exchange specifications which also includes vCards. You may come across them either in emails or from a website. For example some sites which sell travel tickets allow you to download your itinerary in an iCalendar file. While Windows Phone has always supported vCards for contact information it doesn't recognise iCal files.

Since Windows Phone 8 introduced the ability to register for file associations this allowed me to use some old code I wrote back in the days of Pocket Outlook on Windows CE and Windows Mobile. My free iCalendar Import application has just become available in the Store for Windows Phone 8. You can download it from the link below. I'd welcome any feedback. There are some limitations on the supported event types - there is no way to insert recurring appointments into the user's calendar so this supports single events only.

http://www.windowsphone.com/s?appid=95287e45-05d7-4a63-aa82-619192cb1713

Windows Phone SDK 7.1.1

Peter Foot — Mon, 27 Feb 2012 11:49:00 GMT

At MWC today Nokia announced the Lumia 610 which is a lower spec device designed for emerging markets. This is running an updated Windows Phone OS which supports devices with just 256MB of RAM. To enable developers to create apps which support the new lower memory devices Microsoft are releasing an update to the Windows Phone SDK - 7.1.1.

At the moment a CTP has been released so that you can test your applications on a 256MB emulator but you should not install this to your main development machine as it doesn't have a Go-Live license. To try out the new SDK you can download the CTP here:-

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=28962

There is just one API addition to support this change which is an additional property available from Microsoft.Phone.Info.DeviceExtendedProperties.GetValue - "ApplicationWorkingSetLimit" which will let you know whether you are running on a device with 256MB RAM. If your app/game is sufficiently resource heavy that you don't feel it will run on such a device you can opt out so that your app/game will not be available on these lower powered devices. This is done by adding the Requirements element to your WMAppManifest.xml:-

The other main difference for these devices is there is no support for Background tasks - either Periodic or ResourceIntensive and attempting to add a background task on one of these devices will throw an InvalidOperationException - so it's important to to check the capabilities first. Because of this limitation you need to design your app such that it doesn't rely on a background task and that whatever sync/processing the task normally performs can be done when the app is running in the foreground.

Microsoft have prepared some information on optimising apps for 256MB and it is available here:-

http://msdn.microsoft.com/en-us/library/hh855081(v=vs.92).aspx

Some of the suggestions including using the built in launchers and choosers rather than running functionality such as the WebBrowser control or Bing Maps control within your app. They also suggest avoiding using the page transitions provided by the Silverlight Toolkit but don't suggest an alternative - not sure if this means these devices don't have the smooth page transitions at all or if they are suggesting that doing them from managed code is too resource intensive. You may decide to implement multiple approaches and use different methods depending on the device capabilities. Obviously the trick here is the balance between providing the best possible experience on each platform and avoiding adding too much more code to maintain.

Tasks v1.19

Peter Foot — Wed, 22 Feb 2012 14:28:00 GMT

The latest update to Tasks is now available in the Marketplace. This release continues the improvements to the sync experience by providing more resilience in situations where the network drops out during a sync. It also improves the reminders feature in Windows 7.5 and improves the display of reminders for tasks with very long titles.

http://www.windowsphone.com/en-GB/apps/55fcf880-6b03-e011-9264-00237de2db9e

Follow Up from Windows Phone Camp Bristol

Peter Foot — Sun, 12 Feb 2012 05:58:00 GMT

A few of you who attended the Windows Phone Camp in Bristol asked about the slides and code from the Storing Data and Cloud/Networking session. I've uploaded the latest versions of these slides and the additional Sockets code project to the FTP site. All the links and resources mentioned during the day are on Pete's blog post:-

http://mobileworld.appamundi.com/blogs/petevickers/archive/2011/11/13/links-and-resources-from-windows-phone-camps.aspx

Happy Coding!

Windows Phone Update Due Shortly

Peter Foot — Thu, 05 Jan 2012 20:32:00 GMT

Microsoft have published details of a new update (7.10.8107.79) which adds a number of fixes to the Mango release. It fixes the issue where the on screen keyboard will randomly hide itself which I've been finding frustrating recently and also a fix for the SMS bug which could disable messaging. It also hopefully finally resolves the issue when forwarding Exchange messages where the original message body would disappear. It hasn't shown up yet but expect it over the next couple of weeks. Full details on all the updates and fixes are published here:-

http://www.microsoft.com/windowsphone/en-us/howto/wp7/basics/update-history.aspx

Developer Unlock Expiry

Peter Foot — Wed, 21 Dec 2011 18:35:00 GMT

When you've developer unlocked your Windows Phone you can merrily deploy and debug on it and everything is great. If you've upgraded to Mango you had to run the Unlock tool again but this is fairly painless. What is not obvious is that the developer unlock has a 12 month expiry from when you first register the device and even when you subsequently use the unlock tool on the same device this never gets extended.

So one day you'll be developing as normal and get the error "Failed to connect to device as it is developer locked. For details on developer unlock, visit http://go.microsoft.com/fwlink/?LinkId=195284.". Instictively you launch the developer unlock tool, enter your App Hub credentials and unlock the phone. This completes with no errors but you'll soon find that it hasn't helped despite the fact you entered valid credentials and your App Hub account is valid.

The solution to this problem is to log into App Hub on the web and go to your account profile, select devices and remove the offending device from the list (here you'll see that the expiry date is shown). After doing this you can run the unlock tool again and successfully unlock the device.

Microsoft could certainly improve this process in the future by using a more descriptive error message and also by improving the unlock tool so that when you try to unlock a device that has expired it refreshed the registration and provide 12 more months of use (just like the manual process described above does).

Merry Christmas, and here's to a wonderful 2012 filled with Windows Phone goodness!

Submitting Apps to Marketplace with Background Tasks

Peter Foot — Thu, 08 Dec 2011 06:38:00 GMT

I've been working on an update to the Tasks application which adds in background synchronisation using the new background task support in Windows Phone 7.5. As with any app when you submit your XAP static analysis is performed on it to check, for example, that you have declared the correct capabilities based on the functionality in your app. Within a background agent you are only allow to call a subset of APIs - as you would expect you can't play sound effects or draw to the UI (with the exception of toast notifications and tile updates). Because the main app has to include a reference to the dll which provides the background task, and the functionality within the dll is used in both the background task and the main app it made sense to move all of the logic into the background dll. This meant including a number of third-party references. I was very careful to ensure that nowhere in the background task was any restricted API called and it worked perfectly in testing.

The first problem is that upon submitting the static anaylsis looks at all of the referenced dlls and sees that they contain APIs not permitted in a background task and blocks the XAP. One of the culprits was InTheHand.Phone.dll (Part of Mobile In The Hand) because it provides a mixture of helper classes for logic and for UI. As I've been working on the 7.1 version in tandem I've now split this into two assemblies for Windows Phone 7.1 SDK projects. This means we can continue to use InTheHand.Phone in background tasks and add a reference to the second assembly in the main application only.

The second problem is that code within the sync logic calls ScheduledActionService.Add which is disallowed within a background task. This API is used within Tasks to add system-wide reminders (Another new feature for this version) for new task items. The code also has the ability to update and delete reminders based on modified or deleted tasks but these do not seem to have been flagged up as errors. This is a pain because it means that if the device syncs a new task with a reminder set to show before you next open the foreground app we won't have had a chance to register it.

The other issue with the NeutralResourceLanguage is an issue with projects originally created with an older version of the development tools. You can add this setting from the projects properties, Application tab and click "Assembly Information...".

This has been an interesting learning experience and shows that the validation picks up not just APIs used in the background agent code-path but also in referenced assemblies.

Showing Mango Features on Marketplace

Peter Foot — Tue, 20 Sep 2011 15:30:00 GMT

The Windows Phone team have posted to their blog about application updates with a couple of useful points:-

From October you will again be able to publish updates to your 7.0 apps independently from 7.5 (previously once you had published a Mango update your 7.0 app would be locked). It does mean potentially being in limbo for a month but at least you are not stuck completely with no way of updating a 7.0 app. This is important as it will take some time before many users will have the opportunity of upgrading to Mango.

When submitting apps there is only one description for both versions of your app so you must describe which features are for Mango only. For the purposes of Screenshots there is now an officially accepted overlay which can be used to indicate Mango-only functionality. You can download a ZIP containing the overlay and examples here:-

http://create.msdn.com/downloads/?id=882&filename=Marketplace_7.5_Badges.zip

The full blog post is here:-

http://windowsteamblog.com/windows_phone/b/wpdev/archive/2011/09/20/submit-windows-phone-7-5-apps-today-update-7-0-apps-in-october.aspx?utm_source=twitterfeed&utm_medium=twitter