Posted by Garan Jenkin – Developer Relations Engineer
Put on OS has a thriving watch face ecosystem that includes a wide range of designs that additionally goals to attenuate battery impression. Builders have embraced the simplicity of making watch faces utilizing Watch Face Format – within the final yr, the variety of revealed watch faces utilizing Watch Face Format has grown by over 180%*.
At the 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 precise even larger ranges of creativity by means 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, try the documentation for extra particulars of modifications launched in current variations.
Supporting marketplaces with Watch Face Push
We’re additionally saying a very new API, the Watch Face Push API, aimed toward builders who need to create their very own watch face marketplaces.
Watch Face Push, obtainable on units operating Put on OS 6 and above, works solely 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 will probably 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 approach as publishing by means of Google Play, although there are some extra 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’ve gotten management and accountability for the cellphone app and cloud elements, in addition to for constructing the Put on OS app utilizing Watch Face Push. You’re additionally answerable for the phone-watch communications, for which we suggest utilizing the Knowledge Layer APIs.
Including Watch Face Push to your challenge
To begin utilizing Watch Face Push on Put on OS 6, embody 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:
<uses-permission android:identify="com.google.put on.permission.PUSH_WATCH_FACES" />
Get hold of a Watch Face Push shopper:
val supervisor = WatchFacePushManagerFactory.createWatchFacePushManager(context)
You’re now prepared to start out utilizing the Watch Face Push API, for instance to checklist the watch faces you’ve gotten already put in, or add a brand new watch face:
// Checklist 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 means of the WatchFacePushManager interface, it’s vital 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 way of an extra permission, the app can set the lively watch face. Study easy methods to combine this function, in addition to easy methods to deal with the totally different permission situations.
To study extra about utilizing Watch Face Push, see the steerage and reference documentation.
Updates to Watch Face Format
Images
Out there from Watch Face Format v4
The brand new Images factor permits the watch face to include user-selectable pictures. The factor helps each particular person pictures and a gallery of pictures. For a gallery of pictures, builders can select whether or not the pictures advance robotically or when the person faucets the watch face.
The person is ready to choose the pictures of their alternative by means of the companion app, making this a good way to incorporate true personalization in your watch face. To make use of this function, first add the required configuration:
<UserConfigurations> <PhotosConfiguration id="myPhoto" configType="SINGLE"/> </UserConfigurations>
Then use the Images factor inside any PartImage, in the identical approach as you’d for an Picture factor:
<PartImage ...> <Images supply="[CONFIGURATION.myPhoto]" defaultImageResource="placeholder_photo"/> </PartImage>
For particulars on easy methods to help a number of pictures, and easy methods to configure the totally different change behaviors, seek advice from the Images part of the steerage and reference, in addition to the GitHub samples.
Transitions
Out there from Watch Face Format v4
Watch Face Format now helps transitions when exiting and getting into ambient mode.
That is achieved by means of the prevailing Variant tag. For instance, the hours and minutes within the above watch face are animated as follows:
<DigitalClock ...> <Variant mode="AMBIENT" goal="x" worth="100" interpolation="OVERSHOOT" /> <!-- Remainder of "hh:mm" clock definition right here --> </DigitalClock>
By default, the animation takes the total 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 factor, which exhibits the usage of the brand new length attribute:
<DigitalClock ...> <Variant mode="AMBIENT" goal="alpha" worth="0" length="0.5"/> <!-- Remainder of "ss" clock definition right here --> </DigitalClock>
The length attribute takes a price between 0.0 and 1.0, with 1.0 representing the total 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 your entire transition interval.
For extra particulars on utilizing transitions, see the steerage documentation, in addition to the reference documentation for Variant.
Coloration Transforms
Out there from Watch Face Format v4
We’ve prolonged the usefulness of the Remodel factor by permitting colour to be remodeled on the vast majority of components the place it’s an attribute, and likewise permitting tintColor to be remodeled on Group and Half* components akin to PartDraw and PartText.
The primary exceptions to this addition are the clock components, DigitalClock and AnalogClock, and likewise ComplicationSlot, which don’t at the moment help Remodel.
Along with extending the checklist of transformable attributes to incorporate colours, we’ve additionally added a handful of helpful features for manipulating colour:
To see these in motion, let’s take into account an instance.
The Climate information supply gives the present UV index by means of [WEATHER.UV_INDEX]. When representing the UV index, these values are usually additionally assigned a colour:
We need to signify this info as an Arc, not solely exhibiting the worth, but in addition utilizing the suitable colour. We will obtain this as follows:
<Arc centerX="0" centerY="0" top="420" width="420" startAngle="165" endAngle="165" path="COUNTER_CLOCKWISE"> <Remodel goal="endAngle" worth="165 - 40 * (clamp(11, 0.0, 11.0) / 11.0)" /> <Stroke thickness="20" colour="#ffffff" cap="ROUND"> <Remodel goal="colour" 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)" /> </Stroke> </Arc>
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 checklist of colours
- The second argument is an inventory of weights – you possibly can see from the chart above that inexperienced covers 3 values, whereas orange solely covers 2, so we use weights to signify this.
- The third argument is whether or not or to not interpolate the colour values. On this case we need 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 end result seems like this:
In addition to having the ability to present uncooked colours and weights to those features, they can be used with values from problems, akin to HR, temperature or steps objective. For instance, to make use of the colour vary laid out in a objective complication:
<Remodel goal="colour" worth="extractColorFromColors( [COMPLICATION.GOAL_PROGRESS_COLORS], [COMPLICATION.GOAL_PROGRESS_COLOR_INTERPOLATE], [COMPLICATION.GOAL_PROGRESS_VALUE] / [COMPLICATION.GOAL_PROGRESS_TARGET_VALUE] )"/>
Introducing the Reference factor
Out there from Watch Face Format v4
The brand new Reference factor permits you to seek advice from 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 colour scheme.
We might carry out the identical colour remodel calculation as on our Arc, utilizing [WEATHER.UV_INDEX], however that is duplicative work which might result in inconsistencies, for instance if we alter the precise colour hues in a single place however not the opposite.
Returning to the Arc definition, let’s create a Reference to the colour:
<Arc centerX="0" centerY="0" top="420" width="420" startAngle="165" endAngle="165" path="COUNTER_CLOCKWISE"> <Remodel goal="endAngle" worth="165 - 40 * (clamp(11, 0.0, 11.0) / 11.0)" /> <Stroke thickness="20" colour="#ffffff" cap="ROUND"> <Reference supply="colour" identify="uv_color" defaultValue="#ffffff" /> <Remodel goal="colour" 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)" /> </Stroke> </Arc>
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 have now added a Reference factor, which takes as its supply the Stroke colour.
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 seek advice from this in any expression:
<PartText x="0" y="225" width="450" top="225"> <TextCircular centerX="225" centerY="0" width="420" top="420" startAngle="120" endAngle="90" align="START" path="COUNTER_CLOCKWISE"> <Font household="SYNC_TO_DEVICE" dimension="24"> <Remodel goal="colour" worth="[REFERENCE.uv_color]" /> <Template>%d<Parameter expression="[WEATHER.UV_INDEX]" /></Template> </Font> </TextCircular> </PartText> <!-- Related PartText right here for the "UV:" label -->
Consequently, the colour of the Arc and the UV numeric worth are actually coordinated:
For extra particulars on easy methods to use the Reference factor, seek advice from the Reference steerage.
Textual content autosizing
Out there from Watch Face Format v3
Generally the precise size of the textual content to be proven on the watch face can fluctuate, and as a developer you need to stability having the ability to show textual content that’s each legible, but in addition full.
Auto-sizing textual content may also help clear up this downside, and will be enabled by means of the isAutoSize attribute launched to the Textual content factor:
<Textual content align="CENTER" isAutoSize="true">
Having set this attribute, textual content will then robotically match the obtainable house, beginning on the most dimension laid out in your Font factor, and with a minimal dimension of 12.
For example, step rely might vary from tens or tons of by means of to many hundreds, and the brand new isAutoSize attribute permits greatest use of the obtainable house for each potential worth:
For extra particulars on isAutoSize, see the Textual content reference.
Android Studio help
For builders working in Android Studio, we’ve added help to make working with Watch Face Format simpler, together with:
- Run configuration help
- Auto-complete and useful resource reference
- Lint checking
That is obtainable from Android Studio Canary model 2025.1.1 Canary 10.
Study Extra
To study extra about constructing watch faces, please check out the next sources:
We’ve additionally lately launched a codelab for Watch Face Format and have up to date samples on GitHub to showcase new options. The difficulty tracker is accessible 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 Could 22.
* Google Play information for interval 2024-03-24 to 2025-03-23