Windows (Phone) 8 NFC App Scenarios

Windows (Phone) 8NFC App Scenarios

Andreas Jakl, Mopius

Windows (Phone) 8 NFC App Scenarios v3.0.0 © 2014 Andreas Jakl 1NFC Forum and the NFC Forum logo are trademarks of the Near Field Communication Forum.

Andreas JaklTwitter: @mopius

Email: [email protected]

Trainer & app developer– mopius.com

– nfcinteractor.com

Nokia: Technology Wizard

FH Hagenberg, Mobile Computing: Assistant Professor

Siemens / BenQ Mobile: Augmented Reality-Apps

Windows (Phone) 8 NFC App Scenarios v3.0.0 © 2014 Andreas Jakl 2


Seamless Multi-User Games & CollaborationShare to OthersDiscover Your App

Near Field Communication Nfc InteractorNDEF Library

PROXIMITY & TAPPING


NFC Scenarios

Windows (Phone) 8 NFC App Scenarios v3.0.0 © 2014 Andreas Jakl

Connect Devices Exchange Digital Objects Acquire Content

5

Tap and Do


A gesture that is a natural interaction between people in close proximity used to trigger doing something together between the devices they are holding.

System: Near Field Proximity(e.g., NFC)

Documentation: bit.ly/ProximitySpec


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DocumentationWin8: bit.ly/ProximityAPI

WP8: bit.ly/ProximityAPIwp8

7

APP SCENARIOS


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Seamless Multi-User Games & Collaboration

General Project Setup


1 Add Proximity Capability

2 Initialize ProximityDevice_device = ProximityDevice.GetDefault();

Connect to HWDetect devices in rangePublish & subscribe to messages

How to Launch Apps


Custom URI schemelaunches app.App needs to register.

Tag directly containsapp name andcustom data.No registration necessary.

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Win8 + WP8

11


Directly launch App

parameters app name 1platform 1 platform 2 app name 2 …

* For your low-level interest: type: Absolute URI, type name format: windows.com/LaunchApp. Contents re-formatted, e.g., with string lengths before each value

Encoded into NDEF message*

Write LaunchApp Tags


// Arguments to pass to app, valid for all platformsvar launchArgs = "user=default";

// WP8: app's product id from the app manifest, wrapped in {}var wp8App = "{5e506af4‐4586‐4c90‐bc5f‐428b12cf48bc}";

// Win8: app ID: Package.appxmanifest ‐> source ‐> <Application Id="...">var win8AppId = "Proximity.App";var win8App = Windows.ApplicationModel.Package.Current.Id.FamilyName +

"!" + win8AppId;

// Combine to LaunchApp Messagevar launchAppMessage = launchArgs +

"\tWindowsPhone\t" + wp8App + "\tWindows\t" + win8App;

1 Launch parameters, platforms + app IDs

Write LaunchApp Tags


3 Write to tags_device.PublishBinaryMessage("LaunchApp:WriteTag",

dataWriter.DetachBuffer());

var dataWriter = new Windows.Storage.Streams.DataWriter{UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf16LE};

dataWriter.WriteString(launchAppMessage);

2 Convert to byte array


nearspeak: Good+morning.

Custom dataProtocol name

Encoded Launch URI

Examples*skype:mopius?call

spotify:search:17th%20boulevard

* Definition & examples: http://en.wikipedia.org/wiki/URI_scheme

User Experience


No app installed 1 app installed 2+ apps installed

WP Protocol Association


1 Specify protocol name in WMAppManifest.xml

...</Tokens><Extensions><Protocol Name="nearspeak"

NavUriFragment="encodedLaunchUri=%s"TaskID="_default" />

</Extensions>

Protocol name

Fixed

Note: different in Win8 / WP8



2 Create UriMapper class to parse parametersclass NearSpeakUriMapper : UriMapperBase{

public override Uri MapUri(Uri uri){

// Example: "Protocol?encodedLaunchUri=nearspeak:Good+morning."var tempUri = HttpUtility.UrlDecode(uri.ToString());var launchContents = Regex.Match(tempUri, @"nearspeak:(.*)$").Groups[1].Value;if (!String.IsNullOrEmpty(launchContents)){

// Launched from associated "nearspeak:" protocol// Call MainPage.xaml with parametersreturn new Uri("/MainPage.xaml?ms_nfp_launchargs=" + launchContents, UriKind.Relative);

}

// Include the original URI with the mapping to the main pagereturn uri;

}} Argument already handled in step 9 of LaunchApp tags (MainPage.OnNavigatedTo)

Note: different in Win8 / WP8



3 Use UriMapper in App.xaml.cs(region: )

private void InitializePhoneApplication() {RootFrame = new PhoneApplicationFrame();RootFrame.UriMapper = new NearSpeakUriMapper();

}

– If needed: launch protocol from app (for app2app comm)

await Windows.System.Launcher.LaunchUriAsync(new Uri("nearspeak:Good+morning."));

Register for URI Schemes


Win 8

Specify URI scheme, display name + optional im

20

Tag Data After Launch

Activtion arguments in App.xaml.cs


protected override async void OnActivated(IActivatedEventArgs args){

if (args.Kind == ActivationKind.Protocol){

ProtocolActivatedEventArgs protocolArgs = args asProtocolActivatedEventArgs;

}}

Win 8

21

User Experience


Win 8

22

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Publish Messages

Proximity devices only

– (doesn’t write tags)

Windows Protocol + URI record

– Encapsulated in NDEF


_publishingMessageId = _device.PublishUriMessage(new Uri("nfcinteractor:compose"));

1 Start publishing

Contains scheme,

platform & App ID

Write Tags


1 Prepare & convert datavar dataWriter =

new Windows.Storage.Streams.DataWriter { UnicodeEncoding = Windows.Storage.Streams.

UnicodeEncoding.Utf16LE};

dataWriter.WriteString("nfcinteractor:compose");var dataBuffer = dataWriter.DetachBuffer();

2 Write tag (no device publication)_device.PublishBinaryMessage("WindowsUri:WriteTag", dataBuffer);

Mandatory encoding

bit.ly/PublishTypes

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Share to Others

Tap for


Quick Data Exchange

ProximityDeviceExchange Windows /

NDEF messages,SNEP protocol

Long Term Connection

PeerFinderAutomatically builds

Bt / WiFi Directsocket connection


Establishing


Long Term Connection

Trigger

Interact with TapNFC

Browse

Start SearchBt, WiFi, etc.

Tap to Trigger


App not installed

App installed

Connection State


PeerFound

1Proximity gesture completeDevices can be pulled away

Connecting /Listening

2Which device initiated tap gesture?→ Connecting, other device Listening

Completed

3Access socket of persistent transport

(e.g., TCP/IP, Bt)

Find Peers


PeerFinder.TriggeredConnectionStateChanged +=TriggeredConnectionStateChanged;

PeerFinder.Start();

1 Start waiting for triggered connections

2 Peer found & connection established? Send message over socket

* For URI records + simple Smart Poster (w/o title), use the WindowsUri type.

private async void TriggeredConnectionStateChanged(object sender, TriggeredConnectionStateChangedEventArgs eventArgs) {

if (eventArgs.State == TriggeredConnectState.Completed) {// Socket connection established!var dataWriter = new DataWriter(eventArgs.Socket.OutputStream);dataWriter.WriteString("Hello Peer!");var numBytesWritten = await dataWriter.StoreAsync();

}}Completed

3

TOOLS & RESOURCES


UX Recommendations*

User initiated peer search only Ask for consent Show connection

state

Failed connection?

Inform & revert to single-user mode

Let user get out of proximity

experience

Proximity: only if connection details

not relevant

Windows (Phone) 8 NFC App Scenarios v3.0.0 © 2014 Andreas Jakl 33* bit.ly/ProximityUX

NFC ToolsProximity Tapper for WP emulator

– http://proximitytapper.codeplex.com/

Open NFC Simulator

– http://open-nfc.org/wp/editions/android/

NFC plugin for Eclipse: NDEF Editor

– https://code.google.com/p/nfc-eclipse-plugin/


nfcinteractor.com


NFC Resources NFC News: nfcworld.com

NFC developer comparison

(WP, Android, BlackBerry):

bit.ly/NfcDevCompare

Specifications: nfc-forum.org


NDEF HANDLINGStandardized NFC Tag Contents


NDEF Message

NFC Data


NDEF Record(e.g., URL) …

NDEF = NFC Data Exchange Format

38

SNEP = Simple NDEF Exchange Protocol


NDEF Message

NDEF Record(e.g., URL) …

39

Reading NDEF


_subscribedMessageId = _device.SubscribeForMessage("NDEF", MessageReceivedHandler);

1 Subscribe to all NDEF messages

2 Parse raw byte array in handler

http://www.nfc-forum.org/specs/

_subscribedMessageId = _device.SubscribeForMessage("NDEF", MessageReceivedHandler);

Subscribe to all NDEF messages

Parse raw byte array in handler

http://www.nfc-forum.org/specs/

// Convert the language code to a byte arrayvar languageEncoding = Encoding.UTF8;var encodedLanguage = languageEncoding.GetBytes(languageCode);// Encode and convert the text to a byte arrayvar encoding = (textEncoding == TextEncodingType.Utf8) ? Encoding.UTF8 : Encoding.BigEndianUnicode;var encodedText = encoding.GetBytes(text);// Calculate the length of the payload & create the arrayvar payloadLength = 1 + encodedLanguage.Length + encodedText.Length;Payload = new byte[payloadLength];

// Assemble the status bytePayload[0] = 0; // Make sure also the RFU bit is set to 0// Text encodingif (textEncoding == TextEncodingType.Utf8)

Payload[0] &= 0x7F; // ~0x80else

Payload[0] |= 0x80;

// Language code lengthPayload[0] |= (byte)(0x3f & (byte)encodedLanguage.Length);

// Language codeArray.Copy(encodedLanguage, 0, Payload, 1, encodedLanguage.Length);

// TextArray.Copy(encodedText, 0, Payload, 1 + encodedLanguage.Length, encodedText.Length);Si

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Reading NDEF


1

2

NDEF.codeplex.com


Reusable NDEF classes

Create NDEFmessages & records

(standard compliant)

Parse informationfrom raw byte arrays

Fully documentedOpen Source LGPL license

(based on Qt Mobility)

NDEF Subscriptions


_subscribedMessageId = _device.SubscribeForMessage("NDEF",MessageReceivedHandler);

1 Subscribe to all NDEF formatted tags

private void MessageReceivedHandler(ProximityDevice sender, ProximityMessage message){

var msgArray = message.Data.ToArray();NdefMessage ndefMessage = NdefMessage.FromByteArray(msgArray);[...]

}

2 Parse NDEF message

NDEF Subscriptions


foreach (NdefRecord record in ndefMessage) {

Debug.WriteLine("Record type: " + Encoding.UTF8.GetString(record.Type, 0, record.Type.Length));

// Check the type of each record ‐ handling a Smart Poster in this exampleif (record.CheckSpecializedType(false) == typeof(NdefSpRecord)) {

// Convert and extract Smart Poster infovar spRecord = new NdefSpRecord(record);Debug.WriteLine("URI: " + spRecord.Uri);Debug.WriteLine("Titles: " + spRecord.TitleCount());Debug.WriteLine("1. Title: " + spRecord.Titles[0].Text);Debug.WriteLine("Action set: " + spRecord.ActionInUse());

}}

3 Analyze all contained NDEF records with specialized classes

Write NDEF


1 Prepare & convert data// Initialize Smart Poster record with URI, Action + 1 Titlevar spRecord = new NdefSpRecord

{ Uri = "http://www.nfcinteractor.com" };spRecord.AddTitle(new NdefTextRecord

{ Text = "Nfc Interactor", LanguageCode = "en" });

// Add record to NDEF messagevar msg = new NdefMessage { spRecord };

2a Write tag// Publish NDEF message to a tag_device.PublishBinaryMessage("NDEF:WriteTag", msg.ToByteArray().AsBuffer());

2b Publish to devices// Alternative: send NDEF message to another NFC device_device.PublishBinaryMessage("NDEF", msg.ToByteArray().AsBuffer());

Supported Record Types


Smart Poster URI

Text LaunchApp

Android Application Record (AAR)Windows Phone SettingsNokia Accessories Record

NearSpeak Voice Messages

Geo tagsSocial tagsSMS tagsTelephone callMailto tags

ndef.mopius.com


Seamless Multi-User Games & CollaborationShare to OthersDiscover Your App

Near Field Communication Nfc InteractorNDEF Library

Thank You.

Andreas Jakl@mopius

mopius.comnfcinteractor.com


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