Android Bluetooth

                    All of the Bluetooth APIs are available in the android.bluetooth package. Here's a summary of the classes and interfaces you will need to create Bluetooth connections:

BluetoothAdapter

Represents the local Bluetooth adapter (Bluetooth radio). The BluetoothAdapter is the entry-point for all Bluetooth interaction. Using this, you can discover other Bluetooth devices, query a list of bonded (paired) devices, instantiate a BluetoothDevice using a known MAC address, and create a BluetoothServerSocket to listen for communications from other devices.

BluetoothDevice

Represents a remote Bluetooth device. Use this to request a connection with a remote device through a BluetoothSocket or query information about the device such as its name, address, class, and bonding state.

BluetoothSocket

Represents the interface for a Bluetooth socket (similar to a TCP Socket). This is the connection point that allows an application to exchange data with another Bluetooth device via InputStream and OutputStream.

BluetoothServerSocket

Represents an open server socket that listens for incoming requests (similar to a TCP ServerSocket). In order to connect two Android devices, one device must open a server socket with this class. When a remote Bluetooth device makes a connection request to the this device, the BluetoothServerSocket will return a connected BluetoothSocket when the connection is accepted.

BluetoothClass

Describes the general characteristics and capabilities of a Bluetooth device. This is a read-only set of properties that define the device's major and minor device classes and its services. However, this does not reliably describe all Bluetooth profiles and services supported by the device, but is useful as a hint to the device type.

BluetoothProfile

An interface that represents a Bluetooth profile. A Bluetooth profile is a wireless interface specification for Bluetooth-based communication between devices. An example is the Hands-Free profile. For more discussion of profiles, see Working with Profiles

BluetoothHeadset

Provides support for Bluetooth headsets to be used with mobile phones. This includes both Bluetooth Headset and Hands-Free (v1.5) profiles.

BluetoothA2dp

Defines how high quality audio can be streamed from one device to another over a Bluetooth connection. "A2DP" stands for Advanced Audio Distribution Profile.

BluetoothHealth

Represents a Health Device Profile proxy that controls the Bluetooth service.

BluetoothHealthCallback

An abstract class that you use to implement BluetoothHealth callbacks. You must extend this class and implement the callback methods to receive updates about changes in the application’s registration state and Bluetooth channel state.

BluetoothHealthAppConfiguration

Represents an application configuration that the Bluetooth Health third-party application registers to communicate with a remote Bluetooth health device.

BluetoothProfile.ServiceListener

An interface that notifies BluetoothProfile IPC clients when they have been connected to or disconnected from the service (that is, the internal service that runs a particular profile).

Bluetooth Permissions

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In order to use Bluetooth features in your application, you need to declare at least one of two Bluetooth permissions: BLUETOOTH and BLUETOOTH_ADMIN.
You must request the BLUETOOTH permission in order to perform any Bluetooth communication, such as requesting a connection, accepting a connection, and transferring data.
You must request the BLUETOOTH_ADMIN permission in order to initiate device discovery or manipulate Bluetooth settings. Most applications need this permission solely for the ability to discover local Bluetooth devices. The other abilities granted by this permission should not be used, unless the application is a "power manager" that will modify Bluetooth settings upon user request. Note: If you use BLUETOOTH_ADMIN permission, then must also have the BLUETOOTH permission.
Declare the Bluetooth permission(s) in your application manifest file. For example:

 
<manifest ... >
  <uses-permission android:name="android.permission.BLUETOOTH" />
  ...
</manifest>

See the <uses-permission> reference for more information about declaring application permissions.

Setting Up Bluetooth

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Before your application can communicate over Bluetooth, you need to verify that Bluetooth is supported on the device, and if so, ensure that it is enabled.
If Bluetooth is not supported, then you should gracefully disable any Bluetooth features. If Bluetooth is supported, but disabled, then you can request that the user enable Bluetooth without leaving your application. This setup is accomplished in two steps, using the BluetoothAdapter.

1. Get the BluetoothAdapter The BluetoothAdapter is required for any and all Bluetooth activity. To get the BluetoothAdapter, call the static getDefaultAdapter() method. This returns a BluetoothAdapter that represents the device's own Bluetooth adapter (the Bluetooth radio). There's one Bluetooth adapter for the entire system, and your application can interact with it using this object. If getDefaultAdapter() returns null, then the device does not support Bluetooth and your story ends here. For example:
   

    
   BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
   if (mBluetoothAdapter == null) {
       // Device does not support Bluetooth
   }

2. Enable Bluetooth Next, you need to ensure that Bluetooth is enabled. Call isEnabled() to check whether Bluetooth is currently enable. If this method returns false, then Bluetooth is disabled. To request that Bluetooth be enabled, call startActivityForResult() with the ACTION_REQUEST_ENABLE action Intent. This will issue a request to enable Bluetooth through the system settings (without stopping your application). For example:
   

    
   if (!mBluetoothAdapter.isEnabled()) {
       Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
       startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
   }