Google Fit, Android Wear & Xamarin

Google Fit, Wear & Xamarin
Peter Friese @peterfriese
Matt Sullivan @mjohnsullivan

Are Fitness apps just for
runners, cyclists, athletes?
Or for those on a mission to get
fit and stay healthy?

Can we add elements of fitness
to everyday apps?

http://handy-games.com/games/kitty-my-fitness-cat/

Positive impact on physical and
emotional wellbeing
==
positive impact on user
experience and happiness

Create a Wear app module
Design the watch face UI
Extend WatchFaceService.Engine
Create a companion app
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Watch Face Architecture
Wearable App
CanvasWatchFaceService
Engine
WearableConfigActivity
WearableListenerService
Mobile App
MobileConfigActivity

Design for square
and round
Interactive and
Ambient Modes
Gestures

CanvasWatchFaceService.Engine
UI Drawing
Manually draw onto
a Canvas Object
Ambient Mode Changes
Reduced color space
Burn protection
Redraw Intervals
Once a minute in
Ambient – OnTimeTick()
Custom for interactive
– use a System Timer
TimeZone Changes
Use a BroadcastReceiver
Interactive Watch Faces
.SetAcceptsTapEvents() in Builder
Override OnTapCommand()

Drawing the watch face
Background
Hour Ticks
Step Count
Minutes Hand
Seconds Hand
Hours Hand

backgroundScaledBitmap =
Bitmap.CreateScaledBitmap(backgroundBitmap, 
width, height, true); 
canvas.DrawBitmap(backgroundScaledBitmap, 0, 0, null); 
 
Drawing the Watch Face - Background

var innerTickRadius = centerX - 10; 
var outerTickRadius = centerX; 
for (var tickIndex = 0; tickIndex < 12; tickIndex++) 
{ 
var tickRot = (float)(tickIndex * Math.PI * 2 / 12); 
var innerX = (float)Math.Sin(tickRot) * innerTickRadius; 
var innerY = (float)-Math.Cos(tickRot) * innerTickRadius; 
var outerX = (float)Math.Sin(tickRot) * outerTickRadius; 
var outerY = (float)-Math.Cos(tickRot) * outerTickRadius;
 
canvas.DrawLine(centerX + innerX, centerY + innerY, 
centerX + outerX, centerY + outerY, tickPaint); 
} 
 
Drawing the Watch Face - Ticks

var width = bounds.Width(); 
var height = bounds.Height(); 
 
var steps = stepCount.ToString(); 
var stepsWidth = stepcountPaint.MeasureText(steps); 
 
var x = width - stepsWidth - stepCountOffset; 
var y = (height + stepCountTextSize) / 2.0f; 
 
canvas.DrawText(steps, x, y, stepcountPaint); 
Drawing the Watch Face - Step Count

Ambient mode
Reduce color depth
Reduce number of non-black pixels
Use color for < 5% pixels
Watch face updates
once a minute -
don’t show seconds
Save power
Interactive Ambient

public override void OnDraw(Canvas canvas, Rect bounds) 
{ 
DrawFace(canvas, bounds); 
DrawHands(canvas, bounds); 
} 
 
void DrawHands(Canvas canvas, Rect bounds) 
{ 
if (!IsInAmbientMode) { 
canvas.DrawLine(centerX, centerY,
centerX + secX, centerY + secY, secondPaint); 
} 
 
centerX + minX, centerY + minY, minutePaint); 
}
Ambient Mode

public override void OnDraw(Canvas canvas, Rect bounds) 
{ 
DrawFace(canvas, bounds); 
DrawHands(canvas, bounds); 
} 
 
void DrawHands(Canvas canvas, Rect bounds) 
{ 
if (!IsInAmbientMode) { 
centerX + secX, centerY + secY, secondPaint); 
} 
 
centerX + minX, centerY + minY, minutePaint); 
}
Ambient Mode
No seconds hand
in ambient mode

void UpdateTimer() 
{ 
if (timerSeconds == null) { 
timerSeconds = new System.Threading.Timer( 
state => { 
Invalidate(); 
}, 
null, dueTime, period 
} 
else { 
if (IsVisible && !IsInAmbientMode) { 
timerSeconds.Change(0, InteractiveUpdateRateMs); 
} 
else { 
timerSeconds.Change(System.Threading.Timeout.Infinite, 0); 
} 
} 
}
Ambient Mode / 2

{ 
state => { 
Invalidate(); 
}, 
} 
else { 
} 
else { 
} 
} 
}
Ambient Mode / 2
Redraw every second when
in interactive mode

{ 
state => { 
Invalidate(); 
}, 
} 
else { 
} 
else { 
} 
} 
}
Ambient Mode / 2
Turn timer
on in interactive mode
off in ambient mode

Configuration Activities
WEARABLE_CONFIGURATION on Wear
COMPANION_CONFIGURATION on Phone
DataLayer API
Listen for Data Item Events
Write DataItems to URI Paths

void SaveStepCountStatus(GoogleApiClient googleApiClient, bool stepCountOn)
{
var putDataMapRequest = PutDataMapRequest.Create("/xfit_watchface");
putDataMapRequest.DataMap.PutBoolean("stepcount", stepCountOn);
var putDataRequest = putDataMapRequest.AsPutDataRequest();
putDataRequest.SetUrgent();
WearableClass.DataApi.PutDataItem(googleApiClient, putDataRequest);
}
Syncing configuration /1

void SaveStepCountStatus(GoogleApiClient googleApiClient, bool stepCountOn)
{
var putDataMapRequest = PutDataMapRequest.Create("/xfit_watchface");
putDataMapRequest.DataMap.PutBoolean("stepcount", stepCountOn);
var putDataRequest = putDataMapRequest.AsPutDataRequest();
putDataRequest.SetUrgent();
WearableClass.DataApi.PutDataItem(googleApiClient, putDataRequest);
}
URI Path
Data Item Key
Sync now

void OnDataChanged(DataEventBuffer dataEvents)
{
foreach (var dataEvent in dataEvents)
{
var dataItem = dataEvent.DataItem;
if (dataItem.Uri.Path == "/xfit_watchface")
{
var dataMap = DataMapItem.FromDataItem(dataItem).DataMap;
displayStepCount = dataMap.GetBoolean(“stepcount”);
Invalidate(); // force redraw
}
}
}

void OnDataChanged(DataEventBuffer dataEvents)
{
foreach (var dataEvent in dataEvents)
{
var dataItem = dataEvent.DataItem;
if (dataItem.Uri.Path == "/xfit_watchface")
{
var dataMap = DataMapItem.FromDataItem(dataItem).DataMap;
displayStepCount = dataMap.GetBoolean(“stepcount”);
Invalidate(); // force redraw
}
}
}
Implements IDataApiDataListener
URI Path
Data Item Key

Watch face drawing code
GoogleAPIClient code
Configuration code
Reading the step count code
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Partial Classes
XFitWatchfaceService
XFitWatchFaceEngine
(Drawing Code)
XFitWatchFaceEngine
(Config Code)
XFitWatchFaceEngine
(Google API Client Code)
XFitWatchFaceEngine
(Step Count Code)
XFitWatchFaceEngine

Partial Classes
XFitWatchFaceEngine
(Drawing Code)
XFitWatchFaceEngine
(Config Code)
XFitWatchFaceEngine
XFitWatchFaceEngine
(Step Count Code)
XFitWatchFaceEngine
[Service(Label = "XFit Watchface 4",
Permission = "android.permission.BIND_WALLPAPER")] 
[IntentFilter(new[] { "android.service.wallpaper.WallpaperService" },
Categories = new[]
{ "com.google.android.wearable.watchface.category.WATCH_FACE" })] 
public partial class XFitWatchfaceService: CanvasWatchFaceService 
{ 
 
public override WallpaperService.Engine OnCreateEngine() 
{ 
return new XFitWatchfaceEngine(this); 
} 
 
partial class XFitWatchfaceEngine : Engine 
{
// drawing code 
}
}
XFitWatchfaceService.cs (Drawing Code)

Partial Classes
XFitWatchFaceEngine
(Drawing Code)
XFitWatchFaceEngine
(Config Code)
XFitWatchFaceEngine
XFitWatchFaceEngine
(Step Count Code)
XFitWatchFaceEngine
[MetaData(
"com.google.android.wearable.watchface.wearableConfigurationAction",
Value = "XFitWatchface.CONFIG")] 
[MetaData(
"com.google.android.wearable.watchface.companionConfigurationAction",
Value = "XFitWatchface.CONFIG")]
public partial class XFitWatchfaceService : CanvasWatchFaceService 
{ 
 
partial class XFitWatchfaceEngine : Engine, IDataApiDataListener 
{ 
void ConnectWatchfaceConfigUpdates()
{ 
} 
} 
} 
XFitWatchfaceServiceConfig.cs (Config Code)

Partial Classes
XFitWatchFaceEngine
(Drawing Code)
XFitWatchFaceEngine
(Config Code)
XFitWatchFaceEngine
XFitWatchFaceEngine
(Step Count Code)
XFitWatchFaceEngine
public partial class XFitWatchfaceService : CanvasWatchFaceService 
{ 
 
partial class XFitWatchfaceEngine : Engine 
{ 
GoogleApiClient googleApiClient; 
 
void ConnectGoogleApiClient() 
{ 
googleApiClient = new GoogleApiClient.Builder(owner)
.AddApi(FitnessClass.HISTORY_API) 
.AddApi(FitnessClass.RECORDING_API) 
.AddApi(WearableClass.API)
.Build();
googleApiClient.Connect(); 
} 
} 
}
XFitWatchfaceServiceGoogleApiClient.cs (Google API Client)

Activity Read/Write
Body Read/Write
Location Read/Write
Nutrition Read/Write

Sleep Duration & Type
Calories Consumed, Macronutrients
Height, Weight, BMI, Body Fat %
Heart Rate
Distance Traveled
Steps
Calories Burned
Activity Segments (walking, running, biking)
Gym Activities
ACTIVITY
NUTRITION
BODY
SLEEP

SENSORS API
RECORDING API
HISTORY API
SESSIONS API

SENSORS API
Find all sensors, both on and off-device
FindDataSources (GoogleApiClient c, DataSourcesRequest r)
Register for sensor data
Add (GoogleApiClient c, SensorRequest r, IOnDataPointListener l);
Unregister for sensor data
Remove (GoogleApiClient c, IOnDataPointListener l);

RECORDING API
Stop recording data types/sources
Unsubscribe (GoogleApiClient c, DataType t)
Unsubscribe (GoogleApiClient c, DataSource s)
What data is being recorded
ListSubscriptions (GoogleApiClient c)
Record from data types/sources
Subscribe (GoogleApiClient c, DataType t)
Subscribe (GoogleApiClient c, DataSource s)

HISTORY API
Manually add data
InsertData (GoogleApiClient c, DataSet d)
Remove data
DeleteData (GoogleApiClient c, DeleteDataRequest r)
Retrieve data
void ReadData (GoogleApiClient c, DataReadRequest r)

SESSIONS API
Start recording a live session
void StartSession(GoogleApiClient client, Session session);
Stop recording a live session
void StopSession (GoogleApiClient client, String identifier);
Insert a session
void InsertSession (GoogleApiClient client, SessionInsertRequest request)

curl
-H "Content-Type: application/json"
-H "Authorization: Bearer $ACCESS_TOKEN"
https://www.googleapis.com/fitness/v1/users/me/dataSources/
derived:com.google.step_count.delta:...:estimated_steps/
datasets/1438701040000000000-143930584000000000
REST API

Create a GoogleApiClient
Ensure device is recording steps
Build an aggregated query
Read and extract the data
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void BuildApiClient ()
{
googleApiClient = new GoogleApiClient.Builder (this)
.AddApi (FitnessClass.HISTORY_API)
.AddApi (FitnessClass.RECORDING_API)
.AddScope (FitnessClass.ScopeActivityReadWrite)
.EnableAutoManage (this, AuthClientId,
result => {
// Unresolvable error, handle or fail silently
})
.Build ();
SubscribeToSteps ();
ReadSteps ();
}
Read before connection
established
Auto manage
connection
Build API Client

void SubscribeToSteps ()
{
FitnessClass.RecordingApi.Subscribe (googleApiClient,
TypeStepCountDelta)
.SetResultCallback( (IResult result) => {
if (!result.Status.IsSuccess)
{
// Error subscribing, handle
}
});
}
Subscribing

// Read step count deltas from the History API
DataReadRequest DailyStepsForWeek()
{
long midnight = TimeUtility.MidnightLocalPosix ();
long midnightWeekAgo = TimeUtility.DaysAgoPosix (midnight, 7);
return new DataReadRequest.Builder ()
.Aggregate (DataType.TypeStepCountDelta,
DataType.AggregateStepCountDelta)
.BucketByTime (1, TimeUnit.Days)
.SetTimeRange (midnightWeekAgo, midnight,
TimeUnit.Milliseconds)
.Build();
}
Data
Aggregation
Data Read Request

// Reads and extracts step data
void ReadDailySteps ()
{
DataReadRequest readRequest = RequestBuilder.DailyStepsForWeek ();
FitnessClass.HistoryApi.ReadData (googleApiClient, readRequest)
.SetResultCallback ( (IResult result) => {
IList<Bucket> buckets = ((DataReadResult)result).Buckets;
foreach (var bucket in buckets)
{
var stepCount = bucket.DataSets.Sum(dataSet =>
dataSet.DataPoints.Sum (dp =>
dp.DataType.Fields.Sum (f =>
dp.GetValue (f).AsInt())));
Log.Info (Tag, $"Step Count: {stepCount}");
}
});
}
Reading
Data
Extracting
Data
Read Daily Steps

// Writing data
googleApiClient = new GoogleApiClient.Builder(context)
.AddApi(...)
.AddConnectionCallbacks(
connectionHint => { // Connected! },
cause => { // Suspended }
).Build();
Writes require
an established
connection
Writing Data

Build an aggregated query
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// All in one reading steps
void AllInOne()
{
var client = new GoogleApiClient.Builder (this)
.AddApi (FitnessClass.HISTORY_API)
.UseDefaultAccount ()
.Build ();
client.Connect ();
FitnessClass.HistoryApi.ReadDailyTotal (client, TypeStepCountDelta)
.SetResultCallback ( (IResult result) => {
DataSet ds = ((DailyTotalResult) result).Total;
int stepCount = ds.DataPoints.Sum (
dp => dp.DataType.Fields.Sum (
f => dp.GetValue (f).AsInt()));
});
}
Default
Account Read Daily Total
Read Today’s Steps

Thank You!
https://developers.google.com/fit/
https://developer.android.com/wear/
http://developer.android.com/training/wearables/watch-faces/

Google Fit, Android Wear & Xamarin

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