API reference

AutoDeviceSelector Class

Extends DeviceSelectorBase
 Modifiers: final
A device selector that automatically selects an optimal device from the provided device set. Uses a reactive stream approach that maintains device selection across connectivity changes, only switching devices when the currently selected device becomes disconnected or incompatible.
This selector is ideal for most applications that want to connect to any available device without requiring the user to manually select one. The selector continuously monitors device connectivity and compatibility, automatically switching to the best available device when the current device disconnects or becomes incompatible.
Example: 
// Use default selection (first connected, compatible device)
val session = Wearables.createSession(AutoDeviceSelector())
// Custom ranking: prefer devices by name
val customRanking = Comparator<Device> { a, b -> a.name.compareTo(b.name) }
val session = Wearables.createSession(AutoDeviceSelector(customRanking))

See Also

Constructors

AutoDeviceSelector ( deviceRanking , filter )
Signature 
constructor(deviceRanking: Comparator<Device>), filter: (Device) -> Boolean = { true })
Parameters
deviceRanking: Comparator<Device>  A comparator function used to rank and select from connected devices when the current device is no longer connected or compatible. The default ranking prioritizes connected devices first.
filter: Function1  An additional filter applied on top of the default connected and compatible check. Only devices that are both connected/compatible AND pass this filter will be considered. The default accepts all connected and compatible devices.
Returns
AutoDeviceSelector

Methods

activeDevice ()
Returns the currently selected device identifier, or null if no device is selected.
This provides synchronous access to the latest selected device. The value is eagerly cached from the underlying device selection flow, so it always reflects the most recent state without requiring flow collection.
Signature 
open override fun activeDevice(): DeviceIdentifier?
Returns
DeviceIdentifier?  The DeviceIdentifier of the currently selected device, or null if no suitable device is available
activeDeviceFlow ()
Returns a Flow that emits the currently selected device identifier, or null when no device is selected.
Use this to reactively observe device selection changes. The flow emits whenever the selected device changes — for example, when a device connects, disconnects, or when the selector switches to a different device.
Signature 
open override fun activeDeviceFlow(): Flow<DeviceIdentifier?>
Returns
Flow<DeviceIdentifier?>  A Flow of DeviceIdentifier representing the active device, or null when no suitable device is available