Add complications to a watch face

A watch face complication displays data from a data source. With the Complications API, watch faces can choose the data sources they want to use to get the underlying data. This lets watch faces display information beyond the time of day without needing code for getting the data.

Use a ComplicationSlotsManager

To add complications to a watch face, use a ComplicationSlotsManager.

The ComplicationSlotsManager defines how many complications a watch face supports and where they are positioned on the screen. To support changing the location or number of complications, the ComplicationSlotsManager also uses the CurrentUserStyleRepository, as shown in the following example:

 override fun createComplicationSlotsManager(
        currentUserStyleRepository: CurrentUserStyleRepository
    ): ComplicationSlotsManager {
        val defaultCanvasComplicationFactory =
            CanvasComplicationFactory { watchState, listener ->
                // ...
            }
    
        val leftComplicationSlot = ComplicationSlot.createRoundRectComplicationSlotBuilder(
            id = 100,
            canvasComplicationFactory = defaultCanvasComplicationFactory,
            // ...
        )
            .setDefaultDataSourceType(ComplicationType.SHORT_TEXT)
            .build()
    
        val rightComplicationSlot = ComplicationSlot.createRoundRectComplicationSlotBuilder(
            id = 101,
            canvasComplicationFactory = defaultCanvasComplicationFactory,
            // ...
        )
            .setDefaultDataSourceType(ComplicationType.SHORT_TEXT)
            .build()

        return ComplicationSlotsManager(
            listOf(leftComplicationSlot, rightComplicationSlot),
            currentUserStyleRepository
        )
 }

Types and fields

The following table describes the types and fields of the ComplicationData object. If a watch face requests a field that is invalid for a complication type, a default value for the field is returned. For example, if a watch face tries to access a LONG_TEXT field in a SHORT_TEXT type, the default value for the LONG_TEXT field, null, is returned.

Type	Required fields	Optional fields	Notes
SHORT_TEXT	Short text	Icon Burn-in protection icon Short title	Shows only one icon or short title if either or both are provided.
ICON	Icon	Burn-in protection icon	Used when text is not needed. The icon is expected to be single color and might be tinted by the watch face.
RANGED_VALUE	Value Min value Max value	Icon Burn-in protection icon Short text Short title	Optional fields are not guaranteed to be displayed. If you want to draw your own progress bar, you can use the isRangedValueProgressHidden() method to hide the progress bar provided by the ComplicationDrawable class.
LONG_TEXT	Long text	Long title Icon Burn-in protection icon Small image	Shows the long title if it's provided.
SMALL_IMAGE	Small image		A small image has one of two styles: photo style or icon style. Photo style means it is expected to fill the space and can be cropped. Icon style means it can't be cropped and can be padded. Image variability can result in an unsuitable image for display in ambient mode on devices with burn-in protection or with low-bit ambient mode. When burn-in protection or low-bit ambient mode is enabled, the watch face might use the burn-in protection small image because it is safe. Otherwise, since it is hard for a watch face to determine suitability, an image isn't displayed.
LARGE_IMAGE	Large image		This image is expected to be large enough to fill the watch face. Image variability can result in an unsuitable image for display in ambient mode on devices with burn-in protection or with low-bit ambient mode. Since it is hard for a watch face to determine suitability for display, a watch face doesn't display an image in ambient mode if burn-in protection or low-bit ambient is enabled.

The following table describes complication types for empty data that can be sent for any complication slot. These types have no fields and don't need to be included in a list of supported types. These types enable watch faces to differentiate among the following three cases:

• No source was chosen
• The user has selected "empty" for a slot
• A source has no data to send

Sources can't send TYPE_EMPTY in response to update requests. Send TYPE_NO_DATA instead.

Complication type	Description
TYPE_NOT_CONFIGURED	Sent by the system when a complication activates but the user has not selected a source and no default was set. Can't be sent by sources.
TYPE_EMPTY	Sent by the system when a complication activates and the user chooses "empty" instead of a source, or when the watch face chooses no source and this complication type as the default. Can't be sent by sources.
TYPE_NO_DATA	Sent by the system when a complication that has a source activates to clear the complication before actual data is received from the source. Can be sent by sources if they have no actual data to send.

For more information, check out the WatchFace sample on GitHub.