Posted by Garan Jenkin – Developer Relations Engineer
Put on OS has a thriving watch face ecosystem that includes quite a lot of designs that additionally goals to attenuate battery affect. Builders have embraced the simplicity of making watch faces utilizing Watch Face Format – within the final yr, the variety of printed watch faces utilizing Watch Face Format has grown by over 180%*.
Right this moment, we’re persevering with our funding and saying model 4 of the Watch Face Format, obtainable as a part of Put on OS 6. These updates permit builders to specific even larger ranges of creativity by way of the brand new options we’ve added. And we’re supporting marketplaces, which supplies flexibility and management to builders and extra alternative for customers.
On this weblog put up we’ll cowl key new options, take a look at the documentation for extra particulars of adjustments launched in latest variations.
Supporting marketplaces with Watch Face Push
We’re additionally saying a totally new API, the Watch Face Push API, geared toward builders who wish to create their very own watch face marketplaces.
Watch Face Push, obtainable on gadgets operating Put on OS 6 and above, works completely with watch faces that use the Watch Face Format watch faces.
We’ve partnered with well-known watch face builders – together with Facer, TIMEFLIK, WatchMaker, Pujie, and Recreative – in designing this new API. We’re excited that each one of those builders can be bringing their distinctive watch face experiences to Put on OS 6 utilizing Watch Face Push.
Watch faces managed and deployed utilizing Watch Face Push are all written utilizing Watch Face Format. Builders publish these watch faces in the identical means as publishing by way of Google Play, although there are some further checks the developer should make that are described within the Watch Face Push steerage.
The Watch Face Push API covers solely the watch a part of this typical market system diagram – because the app developer, you could have management and duty for the cellphone app and cloud parts, in addition to for constructing the Put on OS app utilizing Watch Face Push. You’re additionally in charge of the phone-watch communications, for which we suggest utilizing the Information Layer APIs.
Including Watch Face Push to your venture
To start out utilizing Watch Face Push on Put on OS 6, embrace the next dependency in your Put on OS app:
// Guarantee newest model is utilized by checking the repository implementation("androidx.put on.watchface:watchface-push:1.3.0-alpha07")
Declare the required permission in your AndroidManifest.xml:
"com.google.put on.permission.PUSH_WATCH_FACES" />
Acquire a Watch Face Push shopper:
val supervisor = WatchFacePushManagerFactory.createWatchFacePushManager(context)
You’re now prepared to begin utilizing the Watch Face Push API, for instance to record the watch faces you could have already put in, or add a brand new watch face:
// Record current watch faces, put in by this app val listResponse = supervisor.listWatchFaces() // Add a watch face supervisor.addWatchFace(watchFaceFileDescriptor, validationToken)
Understanding Watch Face Push
Whereas the fundamentals of the Watch Face Push API are simple to know and entry by way of the WatchFacePushManager interface, it’s essential to think about a number of different elements when working with the API in apply to construct an efficient market app, together with:
- Setting lively watch faces – By means of a further permission, the app can set the lively watch face. Find out about the way to combine this characteristic, in addition to the way to deal with the totally different permission eventualities.
To be taught extra about utilizing Watch Face Push, see the steerage and reference documentation.
Updates to Watch Face Format
Pictures
Obtainable from Watch Face Format v4
The brand new Pictures aspect permits the watch face to include user-selectable photographs. The aspect helps each particular person photographs and a gallery of photographs. For a gallery of photographs, builders can select whether or not the photographs advance routinely or when the person faucets the watch face.
The person is ready to choose the photographs of their alternative by way of the companion app, making this an effective way to incorporate true personalization in your watch face. To make use of this characteristic, first add the required configuration:
"myPhoto" configType="SINGLE"/>
Then use the Pictures aspect inside any PartImage, in the identical means as you’ll for an Picture aspect:
"[CONFIGURATION.myPhoto]" defaultImageResource="placeholder_photo"/>
For particulars on the way to assist a number of photographs, and the way to configure the totally different change behaviors, consult with the Pictures part of the steerage and reference, in addition to the GitHub samples.
Transitions
Obtainable from Watch Face Format v4
Watch Face Format now helps transitions when exiting and coming into ambient mode.
That is achieved by way of the present Variant tag. For instance, the hours and minutes within the above watch face are animated as follows:
"AMBIENT" goal="x" worth="100" interpolation="OVERSHOOT" />
By default, the animation takes the complete extent of allowed time for the transition. The brand new interpolation attribute controls the animation impact – on this case the usage of OVERSHOOT provides a playful expertise.
The seconds are applied in a separate DigitalClock aspect, which reveals the usage of the brand new length attribute:
"AMBIENT" goal="alpha" worth="0" length="0.5"/>
The length attribute takes a price between 0.0 and 1.0, with 1.0 representing the complete extent of the allowed time. On this instance, through the use of a price of 0.5, the seconds animation is faster – taking half the allowed time, compared to the hours and minutes, which take all the transition interval.
For extra particulars on utilizing transitions, see the steerage documentation, in addition to the reference documentation for Variant.
Colour Transforms
Obtainable from Watch Face Format v4
We’ve prolonged the usefulness of the Remodel aspect by permitting coloration to be remodeled on the vast majority of parts the place it’s an attribute, and likewise permitting tintColor to be remodeled on Group and Half* parts comparable to PartDraw and PartText.
The primary exceptions to this addition are the clock parts, DigitalClock and AnalogClock, and likewise ComplicationSlot, which don’t presently assist Remodel.
Along with extending the record of transformable attributes to incorporate colours, we’ve additionally added a handful of helpful features for manipulating coloration:
To see these in motion, let’s take into account an instance.
The Climate information supply offers the present UV index by way of [WEATHER.UV_INDEX]. When representing the UV index, these values are sometimes additionally assigned a coloration:
We wish to characterize this data as an Arc, not solely displaying the worth, but in addition utilizing the suitable coloration. We are able to obtain this as follows:
"0" centerY="0" top="420" width="420" startAngle="165" endAngle="165" course="COUNTER_CLOCKWISE"> "endAngle" worth="165 - 40 * (clamp(11, 0.0, 11.0) / 11.0)" /> "20" coloration="#ffffff" cap="ROUND"> "coloration" worth="extractColorFromWeightedColors(#97d700 #FCE300 #ff8200 #f65058 #9461c9, 3 3 2 3 1, false, clamp([WEATHER.UV_INDEX] + 0.5, 0.0, 12.0) / 12.0)" />
Let’s break this down:
- The primary Remodel restricts the UV index to the vary 0.0 to 11.0 and adjusts the sweep of the Arc in accordance with that worth.
- The second Remodel makes use of the brand new extractColorFromWeightedColors perform.
- The first argument is our record of colours
- The second argument is a listing of weights – you’ll be able to see from the chart above that inexperienced covers 3 values, whereas orange solely covers 2, so we use weights to characterize this.
- The third argument is whether or not or to not interpolate the colour values. On this case we wish to stick strictly to the colour conference for UV index, so that is false.
- Lastly within the fourth argument we coerce the UV worth into the vary 0.0 to 1.0, which is used as an index into our weighted colours.
The outcome appears to be like like this:
In addition to with the ability to present uncooked colours and weights to those features, they may also be used with values from problems, comparable to HR, temperature or steps objective. For instance, to make use of the colour vary laid out in a objective complication:
"coloration" worth="extractColorFromColors( [COMPLICATION.GOAL_PROGRESS_COLORS], [COMPLICATION.GOAL_PROGRESS_COLOR_INTERPOLATE], [COMPLICATION.GOAL_PROGRESS_VALUE] / [COMPLICATION.GOAL_PROGRESS_TARGET_VALUE] )"/>
Introducing the Reference aspect
Obtainable from Watch Face Format v4
The brand new Reference aspect means that you can consult with any transformable attribute from one a part of your watch face scene in different components of the scene tree.
In our UV index instance above, we’d additionally just like the textual content labels to make use of the identical coloration scheme.
We may carry out the identical coloration remodel calculation as on our Arc, utilizing [WEATHER.UV_INDEX], however that is duplicative work which may result in inconsistencies, for instance if we modify the precise coloration hues in a single place however not the opposite.
Returning to the Arc definition, let’s create a Reference to the colour:
"0" centerY="0" top="420" width="420" startAngle="165" endAngle="165" course="COUNTER_CLOCKWISE"> "endAngle" worth="165 - 40 * (clamp(11, 0.0, 11.0) / 11.0)" /> "20" coloration="#ffffff" cap="ROUND"> "coloration" identify="uv_color" defaultValue="#ffffff" /> "coloration" worth="extractColorFromWeightedColors(#97d700 #FCE300 #ff8200 #f65058 #9461c9, 3 3 2 3 1, false, clamp([WEATHER.UV_INDEX] + 0.5, 0.0, 12.0) / 12.0)" />
The colour of the Arc is calculated from the comparatively complicated extractColorFromWeightedColors perform. To keep away from repeating this elsewhere in our watch face, we’ve got added a Reference aspect, which takes as its supply the Stroke coloration.
Let’s now have a look at how we will devour this worth in a PartText elsewhere within the watch face. We gave the Reference the identify uv_color, so we will merely consult with this in any expression:
"0" y="225" width="450" top="225"> "225" centerY="0" width="420" top="420" startAngle="120" endAngle="90" align="START" course="COUNTER_CLOCKWISE"> "SYNC_TO_DEVICE" measurement="24"> "coloration" worth="[REFERENCE.uv_color]" /> %d "[WEATHER.UV_INDEX]" />
Because of this, the colour of the Arc and the UV numeric worth at the moment are coordinated:
For extra particulars on the way to use the Reference aspect, consult with the Reference steerage.
Textual content autosizing
Obtainable from Watch Face Format v3
Typically the precise size of the textual content to be proven on the watch face can differ, and as a developer you wish to steadiness with the ability to show textual content that’s each legible, but in addition full.
Auto-sizing textual content may help resolve this drawback, and could be enabled by way of the isAutoSize attribute launched to the Textual content aspect:
"CENTER" isAutoSize="true">
Having set this attribute, textual content will then routinely match the obtainable house, beginning on the most measurement laid out in your Font aspect, and with a minimal measurement of 12.
For instance, step rely may vary from tens or lots of by way of to many hundreds, and the brand new isAutoSize attribute allows finest use of the obtainable house for each potential worth:
For extra particulars on isAutoSize, see the Textual content reference.
Android Studio assist
For builders working in Android Studio, we’ve added assist to make working with Watch Face Format simpler, together with:
- Run configuration assist
- Auto-complete and useful resource reference
- Lint checking
That is obtainable from Android Studio Canary model 2025.1.1 Canary 10.
Be taught Extra
To be taught extra about constructing watch faces, please check out the next assets:
We’ve additionally just lately launched a codelab for Watch Face Format and have up to date samples on GitHub to showcase new options. The concern tracker is out there for offering suggestions.
We’re excited to see the watch face experiences that you simply create and share!
Discover this announcement and all Google I/O 2025 updates on io.google beginning Might 22.
* Google Play information for interval 2025-03-24 to 2025-03-23
