The Bluetooth API includes support for working with Bluetooth profiles. A Bluetooth profile is a wireless interface specification for Bluetooth-based communication between devices, such as the Hands-Free profile. For a mobile device to connect to a wireless headset, both devices must support the Hands-Free profile.
The Bluetooth API provides implementations for the following Bluetooth profiles:
- Headset. The Headset profile provides support for Bluetooth headsets to be
used with mobile phones. Android provides the
BluetoothHeadset
class, which is a proxy for controlling the Bluetooth Headset Service. This includes both Bluetooth Headset and Hands-Free (v1.5) profiles. TheBluetoothHeadset
class includes support for AT commands. For more on this topic, see Vendor-specific AT commands. - A2DP. The Advanced Audio Distribution Profile (A2DP) profile defines how
high-quality audio can be streamed from one device to another over a Bluetooth
connection. Android provides the
BluetoothA2dp
class, which is a proxy for controlling the Bluetooth A2DP Service. - Health Device. Android provides support for the Bluetooth Health Device
Profile (HDP). This lets you create apps that use Bluetooth to communicate
with health devices that support Bluetooth, such as heart-rate monitors, blood
meters, thermometers, scales, and so on. For a list of supported devices and
their corresponding device data specialization codes, see Bluetooth's HDP
Device Data
Specializations.
These values are also referenced in the ISO/IEEE 11073-20601 [7] specification
as
MDC_DEV_SPEC_PROFILE_*
in the Nomenclature Codes Annex. For more information about HDP, see Health Device Profile.
Here are the basic steps for working with a profile:
- Get the default adapter, as described in Bluetooth setup.
- Set up a
BluetoothProfile.ServiceListener
. This listener notifiesBluetoothProfile
clients when they have been connected to or disconnected from the service. - Use
getProfileProxy()
to establish a connection to the profile proxy object associated with the profile. In the following example, the profile proxy object is an instance ofBluetoothHeadset
. - In
onServiceConnected()
, get a handle to the profile proxy object. - Once you have the profile proxy object, use it to monitor the state of the connection and perform other operations that are relevant to that profile.
The following code snippet shows how to connect to a BluetoothHeadset
proxy
object so that you can control the Headset profile:
Kotlin
var bluetoothHeadset: BluetoothHeadset? = null // Get the default adapter val bluetoothAdapter: BluetoothAdapter? = BluetoothAdapter.getDefaultAdapter() private val profileListener = object : BluetoothProfile.ServiceListener { override fun onServiceConnected(profile: Int, proxy: BluetoothProfile) { if (profile == BluetoothProfile.HEADSET) { bluetoothHeadset = proxy as BluetoothHeadset } } override fun onServiceDisconnected(profile: Int) { if (profile == BluetoothProfile.HEADSET) { bluetoothHeadset = null } } } // Establish connection to the proxy. bluetoothAdapter?.getProfileProxy(context, profileListener, BluetoothProfile.HEADSET) // ... call functions on bluetoothHeadset // Close proxy connection after use. bluetoothAdapter?.closeProfileProxy(BluetoothProfile.HEADSET, bluetoothHeadset)
Java
BluetoothHeadset bluetoothHeadset; // Get the default adapter BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); private BluetoothProfile.ServiceListener profileListener = new BluetoothProfile.ServiceListener() { public void onServiceConnected(int profile, BluetoothProfile proxy) { if (profile == BluetoothProfile.HEADSET) { bluetoothHeadset = (BluetoothHeadset) proxy; } } public void onServiceDisconnected(int profile) { if (profile == BluetoothProfile.HEADSET) { bluetoothHeadset = null; } } }; // Establish connection to the proxy. bluetoothAdapter.getProfileProxy(context, profileListener, BluetoothProfile.HEADSET); // ... call functions on bluetoothHeadset // Close proxy connection after use. bluetoothAdapter.closeProfileProxy(bluetoothHeadset);
Vendor-specific AT commands
Apps can register to receive system broadcasts of predefined vendor-specific AT
commands sent by headsets (such as a Plantronics +XEVENT command). For example,
an app could receive broadcasts that indicate a connected device's battery level
and could notify the user or take other action as needed. Create a broadcast
receiver for the
ACTION_VENDOR_SPECIFIC_HEADSET_EVENT
intent to handle vendor-specific AT commands for the headset.
Health Device Profile
Android supports the Bluetooth Health Device Profile (HDP). The Bluetooth Health
API includes the classes
BluetoothHealth
,
BluetoothHealthCallback
,
and
BluetoothHealthAppConfiguration
,
which are described in Key classes and
interfaces.
When using the Bluetooth Health API, it's helpful to understand these key HDP concepts:
- Source
- A health device, such as a weight scale, glucose meter, or thermometer, which transmits medical data to a smart device, such as an Android phone or tablet.
- Sink
- The smart device that receives the medical data. In an HDP app, the
sink is represented by a
BluetoothHealthAppConfiguration
object. - Registration
- The process used to register a sink for communicating with a particular health device.
- Connection
- The process used to open a channel between a health device (source) and a smart device (sink).
Create an HDP app
Here are the basic steps involved in creating an HDP app:
Get a reference to the
BluetoothHealth
proxy object. As with regular headset and A2DP profile devices, you must callgetProfileProxy()
with aBluetoothProfile.ServiceListener
and theHEALTH
profile type to establish a connection with the profile proxy object.Create a
BluetoothHealthCallback
and register an app configuration (BluetoothHealthAppConfiguration
) that acts as a health sink.Establish a connection to a health device.
When connected successfully to a health device, read and write to the health device using the file descriptor. The received data needs to be interpreted using a health manager, which implements the IEEE 11073 specifications.
When done, close the health channel and unregister the app. The channel also closes when there is extended inactivity.