Added in API level 5

BluetoothServerSocket


class BluetoothServerSocket : Closeable
kotlin.Any
   ↳ android.bluetooth.BluetoothServerSocket

A listening Bluetooth socket.

The interface for Bluetooth Sockets is similar to that of TCP sockets: java.net.Socket and java.net.ServerSocket. On the server side, use a BluetoothServerSocket to create a listening server socket. When a connection is accepted by the BluetoothServerSocket, it will return a new BluetoothSocket to manage the connection. On the client side, use a single BluetoothSocket to both initiate an outgoing connection and to manage the connection.

For Bluetooth BR/EDR, the most common type of socket is RFCOMM, which is the type supported by the Android APIs. RFCOMM is a connection-oriented, streaming transport over Bluetooth BR/EDR. It is also known as the Serial Port Profile (SPP). To create a listening BluetoothServerSocket that's ready for incoming Bluetooth BR/EDR connections, use BluetoothAdapter.listenUsingRfcommWithServiceRecord().

For Bluetooth LE, the socket uses LE Connection-oriented Channel (CoC). LE CoC is a connection-oriented, streaming transport over Bluetooth LE and has a credit-based flow control. Correspondingly, use BluetoothAdapter.listenUsingL2capChannel() to create a listening BluetoothServerSocket that's ready for incoming Bluetooth LE CoC connections. For LE CoC, you can use getPsm() to get the protocol/service multiplexer (PSM) value that the peer needs to use to connect to your socket.

After the listening BluetoothServerSocket is created, call accept() to listen for incoming connection requests. This call will block until a connection is established, at which point, it will return a BluetoothSocket to manage the connection. Once the BluetoothSocket is acquired, it's a good idea to call #close() on the BluetoothServerSocket when it's no longer needed for accepting connections. Closing the BluetoothServerSocket will not close the returned BluetoothSocket.

BluetoothServerSocket is thread safe. In particular, #close will always immediately abort ongoing operations and close the server socket.

Summary

Public methods
BluetoothSocket!

Block until a connection is established.

BluetoothSocket!
accept(timeout: Int)

Block until a connection is established, with timeout.

Unit

Immediately close this socket, and release all associated resources.

Int

Returns the assigned dynamic protocol/service multiplexer (PSM) value for the listening L2CAP Connection-oriented Channel (CoC) server socket.

String

Public methods

accept

Added in API level 5
fun accept(): BluetoothSocket!

Block until a connection is established.

Returns a connected BluetoothSocket on successful connection.

Once this call returns, it can be called again to accept subsequent incoming connections.

close can be used to abort this call from another thread.

Return
BluetoothSocket! a connected BluetoothSocket
Exceptions
java.io.IOException on error, for example this call was aborted, or timeout

accept

Added in API level 5
fun accept(timeout: Int): BluetoothSocket!

Block until a connection is established, with timeout.

Returns a connected BluetoothSocket on successful connection.

Once this call returns, it can be called again to accept subsequent incoming connections.

close can be used to abort this call from another thread.

Return
BluetoothSocket! a connected BluetoothSocket
Exceptions
java.io.IOException on error, for example this call was aborted, or timeout

close

Added in API level 5
fun close(): Unit

Immediately close this socket, and release all associated resources.

Causes blocked calls on this socket in other threads to immediately throw an IOException.

Closing the BluetoothServerSocket will not close any BluetoothSocket received from accept().

Exceptions
java.lang.Exception if this resource cannot be closed
java.io.IOException if an I/O error occurs

getPsm

Added in API level 29
fun getPsm(): Int

Returns the assigned dynamic protocol/service multiplexer (PSM) value for the listening L2CAP Connection-oriented Channel (CoC) server socket. This server socket must be returned by the BluetoothAdapter#listenUsingL2capChannel() or android.bluetooth.BluetoothAdapter#listenUsingInsecureL2capChannel(). The returned value is undefined if this method is called on non-L2CAP server sockets.

Return
Int the assigned PSM or LE_PSM value depending on transport

toString

Added in API level 5
fun toString(): String
Return
String a string representation of the object.