BluetoothSocket

See also:

• BluetoothServerSocket
• InputStream
• OutputStream

TYPE_L2CAP

public static final int TYPE_L2CAP

L2CAP socket

Constant Value: 3 (0x00000003)

TYPE_LE

public static final int TYPE_LE

L2CAP socket on LE transport

Constant Value: 4 (0x00000004)

TYPE_RFCOMM

public static final int TYPE_RFCOMM

RFCOMM socket

Constant Value: 1 (0x00000001)

TYPE_SCO

public static final int TYPE_SCO

SCO socket

Constant Value: 2 (0x00000002)

close

public void close ()

Closes this stream and releases any system resources associated with it. If the stream is already closed then invoking this method has no effect.

As noted in AutoCloseable.close(), cases where the close may fail require careful attention. It is strongly advised to relinquish the underlying resources and to internally mark the Closeable as closed, prior to throwing the IOException.

connect

public void connect ()

Attempt to connect to a remote device.

This method will block until a connection is made or the connection fails. If this method returns without an exception then this socket is now connected.

Creating new connections to remote Bluetooth devices should not be attempted while device discovery is in progress. Device discovery is a heavyweight procedure on the Bluetooth adapter and will significantly slow a device connection. Use BluetoothAdapter.cancelDiscovery() to cancel an ongoing discovery. Discovery is not managed by the Activity, but is run as a system service, so an application should always call BluetoothAdapter.cancelDiscovery() even if it did not directly request a discovery, just to be sure.

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

Requires the Manifest.permission.BLUETOOTH_PRIVILEGED permission only when mDataPath is different from ERROR(BluetoothSocketSettings.DATA_PATH_NO_OFFLOAD/android.bluetooth.BluetoothSocketSettings#DATA_PATH_NO_OFFLOAD BluetoothSocketSettings.DATA_PATH_NO_OFFLOAD).
For apps targeting Build.VERSION_CODES.S or or higher, this requires the Manifest.permission.BLUETOOTH_CONNECT permission which can be gained with Activity.requestPermissions(String[], int).

getConnectionType

public int getConnectionType ()

Get the type of the underlying connection.

getInputStream

public InputStream getInputStream ()

Get the input stream associated with this socket.

The input stream will be returned even if the socket is not yet connected, but operations on that stream will throw IOException until the associated socket is connected.

getMaxReceivePacketSize

public int getMaxReceivePacketSize ()

Get the maximum supported Receive packet size for the underlying transport. Use this to optimize the reads done on the input stream, as any call to read will return a maximum of this amount of bytes - or for some transports a multiple of this value.

getMaxTransmitPacketSize

public int getMaxTransmitPacketSize ()

Get the maximum supported Transmit packet size for the underlying transport. Use this to optimize the writes done to the output socket, to avoid sending half full packets.

getOutputStream

public OutputStream getOutputStream ()

Get the output stream associated with this socket.

The output stream will be returned even if the socket is not yet connected, but operations on that stream will throw IOException until the associated socket is connected.

getRemoteDevice

public BluetoothDevice getRemoteDevice ()

Get the remote device this socket is connecting, or connected, to.

isConnected

public boolean isConnected ()

Get the connection status of this socket, ie, whether there is an active connection with remote device.

toString

public String toString ()

Returns a string representation of the object.

finalize

protected void finalize ()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.