Best practice tips for delivering apps for the Lumia 520

Comments

Influencer - Very useful!

Hi Mansewiz,

this looks like a very useful article to me. Thanks. I'd propose to change the title to a more generic title like 'Best practice tips for delivering apps for unequal capable devices', because your article is not specific to the Lumia 520 but may fit a whole class of (maybe future) devices with different capabilities.

Thanks again,

Thomas

influencer 23:37, 23 March 2013 (EET)

Hamishwillee - In discussion

Hi Thomas

Bert (Mansewiz) works for Nokia developer and this was created first as a wiki article in order to get the information out quickly for this specific device. The intention is that this article be used as the base of a device-agnostic article that will go into the Lumia library - just as you have suggested. This wiki article would then become a very "thin" link to that new article covering issues related to only the 520.

In other words, yes, absolutely, will happen. Thanks for spotting this and taking the time to comment.

Regards

Hamish

hamishwillee 00:21, 25 March 2013 (EET)

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This article provides recommended best practices for preparing your Windows Phone apps for the Nokia Lumia 520.

Article Metadata

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Tested with

SDK: Windows Phone SDK 8.0

Devices(s): Lumia 520

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Compatibility

Platform(s): Windows Phone 8.0

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Article

Created: Mansewiz (18 Mar 2013)

Last edited: hamishwillee (22 Mar 2013)

Introduction

The Nokia Lumia 520 does not have all of the hardware features found on more expensive devices, including: front camera, rear camera flash, gyroscope, compass and NFC. As a result there are some apps where it will be necessary to drop functionality, and others where the app use case can't be supported at all.

When a particular sensor is essential to the operation of the application you can opt-out (prevent installation of the app on the device) by specifying the sensor's hardware Id as a requirement in the app's manifest file. If the app can still function without the sensor then you can make run time checks to disable the functionality on less capable devices.

This article provides some best practice tips and techniques how to deal with the missing sensors to make sure that your apps will run smoothly across all the devices of the Windows Phone 8.0 portfolio.

Lumia 520 sensor list

Sensor	Present on Lumia 520	HW Requirement
Accelerometer	Yes
Back Camera	Yes
Compass	No	ID_REQ_MAGNETOMETER
Flash for the Back Camera	No
Front Camera	No	ID_RED_FRONT_CAMERA
GPS	Yes
Gyroscope	No	ID_REQ_GYROSCOPE
NFC	No	ID_REQ_NFC

Preventing installation on unsupported devices ("opting out")

If a sensor is essential to the operation of your app then you can remove it as a Windows Store option for all devices without the sensor. Some examples of typical use cases that can't be supported by the Lumia 520 include:

• Video telephony
• Mirror application using the front camera
• Augmented reality application where the apps need to know the phone direction (North, South, East, West)
• Writing or reading content to/from an NFC tag
• Unlocking a game level, using an NFC tag

To ensure that the app will only be presented for installation to devices with the required hardware, specify the HW Requirement for the sensor in the application manifest file (WMAppManifest.xml). This can be done in Visual Studio as shown below.

Editing HW Requirements in Visual Studio

You can find more information about HW requirements in the Dev Center topic: App capabilities and hardware requirements for Windows Phone.

How to check for sensors at runtime

Applications where sensors are only used to enhance the user experience should check for sensor availability and disable any code/menu options which use the sensor. This will ensure that the application doesn't crash or propose an option that will do nothing due to missing sensors.

Note: If you are checking for sensors at runtime, remember not to also specify the HW Requirement in your manifest file

For example a game with NFC "Tap and share your score" functionality can still be a great game if this sharing method is unavailable, and in this case you would check for the presence of NFC and disable/enable the menu option as necessary. Real-world examples of such applications include Burton and YouSendIt

YouSendIt - Send via NFC button

Burton - uses NFC to connect with friends

The code used to perform the run-time availability checks is sensor-dependent, as shown in the following sections.

NFC / Tap to Share

var nfc = ProximityDevice.GetDefault();
if (nfc == null)
{
        // There is no HW support for tap and share (NFC)
}

Front camera

var sensors = PhotoCaptureDevice.AvailableSensorLocations;
if (!sensors.Any(n => n == CameraSensorLocation.Front))
{
         // This device doesn't have a front camera
};

Flash for the back camera

var flashModes = PhotoCaptureDevice.GetSupportedPropertyValues(CameraSensorLocation.Back, 
                KnownCameraPhotoProperties.FlashMode);
 
if (flashModes.Count == 1)
{
       // Count ==1, only FlashState.Off is supported -> Flash is not available on this device.
}

Compass

_compass = Compass.GetDefault();
if (_compass == null)
{
    // The compass is not available on this device
}

Gyroscope

_gyrometer = Gyrometer.GetDefault();
if (_gyrometer == null)
{
    // The gyroscope is not available on this device
}

The Motion API

Windows Phone 8.0 provides the Microsoft.Devices.Sensors.Motion class, which aggregates data from several sensors (accelerometer, compass, gyroscope) and returns high level information about the phone's orientation and motion. The Motion API will not function on devices where the compass is absent.

Use the following code if you want to check the availability of the motion API at run-time:

 if (!Microsoft.Devices.Sensors.Motion.IsSupported)
{
   // Motion class cannot be used on this device.
}