Tracking the State Transitions

You can develop applications which track the state transitions of devices and drivers. To do so you need to subscribe for the events that are published when such a transition takes place i.e. register an event handler.

You can subscribe for the following events:

Events about peripheral devices

Topics

• PeripheralEventConstants.TOPIC_PERIPHERAL_ADDED – to receive events when peripheral devices are added
• PeripheralEventConstants.TOPIC_PERIPHERAL_REMOVED – to receive events when peripheral devices are removed
• PeripheralEventConstants.TOPIC_PERIPHERAL_DESCRIPTOR_UPDATED – to receive events when a peripheral descriptor is updated
• PeripheralEventConstants.TOPIC_PERIPHERAL_STATUS_UPDATED – to receive events when the status of a peripheral device is updated

Properties

• Peripheral.UID
• PeripheralEventConstants.PROPERTY_PERIPHERAL_STATUS
• PeripheralDescriptor.UID
• Peripheral.INTERFACE
• Peripheral.NAME
• Peripheral.TYPE
• Peripheral.VENDOR
• Peripheral.VERSION

Events about peripheral device drivers

Topics

• DriverEventConstants.TOPIC_DRIVER_STATUS_UPDATED – to receive events when the status of a driver is updated
• DriverEventConstants.TOPIC_DRIVER_OPERATION_PROGRESS – to receive events when a driver operation passes through intermediate phases

Properties

Common Properties

Properties that are common for both event topics:

• PeripheralDescriptor.UID
• DriverEventConstants.PROPERTY_UIDS – an array of peripheral UIDs matching this descriptor
• DriverEventConstants.PROPERTY_DRIVER_OPERATION – the type of driver operation with one of the following values:
  • DriverInfo.OPERATION_INSTALL
  • DriverInfo.OPERATION_START
  • DriverInfo.OPERATION_STOP
  • DriverInfo.OPERATION_UNINSTALL
  • DriverInfo.OPERATION_UPDATE

TOPIC_DRIVER_STATUS_UPDATED Event Properties

• DriverEventConstants.PROPERTY_DRIVER_STATUS – contains the driver status value
• DriverEventConstants.PROPERTY_DRIVER_ERROR_CODE – contains the driver status update error code if an error has occurred during a device driver status update.
• DriverEventConstants.PROPERTY_DRIVER_ERROR_MESSAGE – contains the driver status update error message if an error has occurred during a device driver status update.

TOPIC_DRIVER_OPERATION_PROGRES Event Properties

• DriverEventConstants.PROPERTY_DRIVER_OPERATION_PROGRESS_VALUE – a value in the range [0,100] that represents the driver operation progress in percentage.

For further details about events associated with peripheral devices and their drivers, please see the Peripheral API