added in API level 26

DiscoverySession

public class DiscoverySession
extends Object implements AutoCloseable

java.lang.Object
   ↳ android.net.wifi.aware.DiscoverySession


A class representing a single publish or subscribe Aware session. This object will not be created directly - only its child classes are available: PublishDiscoverySession and SubscribeDiscoverySession. This class provides functionality common to both publish and subscribe discovery sessions:

The close() method must be called to destroy discovery sessions once they are no longer needed.

Summary

Public methods

void close()

Destroy the publish or subscribe session - free any resources, and stop transmitting packets on-air (for an active session) or listening for matches (for a passive session).

NetworkSpecifier createNetworkSpecifierOpen(PeerHandle peerHandle)

Create a setNetworkSpecifier(NetworkSpecifier) for an unencrypted WiFi Aware connection (link) to the specified peer.

NetworkSpecifier createNetworkSpecifierPassphrase(PeerHandle peerHandle, String passphrase)

Create a setNetworkSpecifier(NetworkSpecifier) for an encrypted WiFi Aware connection (link) to the specified peer.

void sendMessage(PeerHandle peerHandle, int messageId, byte[] message)

Sends a message to the specified destination.

Inherited methods

Public methods

close

added in API level 26
void close ()

Destroy the publish or subscribe session - free any resources, and stop transmitting packets on-air (for an active session) or listening for matches (for a passive session). The session may not be used for any additional operations after its destruction.

This operation must be done on a session which is no longer needed. Otherwise system resources will continue to be utilized until the application exits. The only exception is a session for which we received a termination callback, onSessionTerminated().

createNetworkSpecifierOpen

added in API level 26
NetworkSpecifier createNetworkSpecifierOpen (PeerHandle peerHandle)

Create a setNetworkSpecifier(NetworkSpecifier) for an unencrypted WiFi Aware connection (link) to the specified peer. The addTransportType(int) should be set to TRANSPORT_WIFI_AWARE.

This method should be used when setting up a connection with a peer discovered through Aware discovery or communication (in such scenarios the MAC address of the peer is shielded by an opaque peer ID handle). If an Aware connection is needed to a peer discovered using other OOB (out-of-band) mechanism then use the alternative createNetworkSpecifierOpen(int, byte[]) method - which uses the peer's MAC address.

Note: per the Wi-Fi Aware specification the roles are fixed - a Subscriber is an INITIATOR and a Publisher is a RESPONDER.

To set up an encrypted link use the createNetworkSpecifierPassphrase(PeerHandle, String) API.

Parameters
peerHandle PeerHandle: The peer's handle obtained through onServiceDiscovered(PeerHandle, byte[], java.util.List) or onMessageReceived(PeerHandle, byte[]). On a RESPONDER this value is used to gate the acceptance of a connection request from only that peer.

This value must never be null.

Returns
NetworkSpecifier A NetworkSpecifier to be used to construct setNetworkSpecifier(NetworkSpecifier) to pass to requestNetwork(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback) [or other varieties of that API].

createNetworkSpecifierPassphrase

added in API level 26
NetworkSpecifier createNetworkSpecifierPassphrase (PeerHandle peerHandle, 
                String passphrase)

Create a setNetworkSpecifier(NetworkSpecifier) for an encrypted WiFi Aware connection (link) to the specified peer. The addTransportType(int) should be set to TRANSPORT_WIFI_AWARE.

This method should be used when setting up a connection with a peer discovered through Aware discovery or communication (in such scenarios the MAC address of the peer is shielded by an opaque peer ID handle). If an Aware connection is needed to a peer discovered using other OOB (out-of-band) mechanism then use the alternative createNetworkSpecifierPassphrase(int, byte[], String) method - which uses the peer's MAC address.

Note: per the Wi-Fi Aware specification the roles are fixed - a Subscriber is an INITIATOR and a Publisher is a RESPONDER.

Parameters
peerHandle PeerHandle: The peer's handle obtained through onServiceDiscovered(PeerHandle, byte[], java.util.List) or onMessageReceived(PeerHandle, byte[]). On a RESPONDER this value is used to gate the acceptance of a connection request from only that peer.

This value must never be null.

passphrase String: The passphrase to be used to encrypt the link. The PMK is generated from the passphrase. Use the createNetworkSpecifierOpen(PeerHandle) API to specify an open (unencrypted) link.

This value must never be null.

Returns
NetworkSpecifier A NetworkSpecifier to be used to construct setNetworkSpecifier(NetworkSpecifier) to pass to requestNetwork(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback) [or other varieties of that API].

sendMessage

added in API level 26
void sendMessage (PeerHandle peerHandle, 
                int messageId, 
                byte[] message)

Sends a message to the specified destination. Aware messages are transmitted in the context of a discovery session - executed subsequent to a publish/subscribe onServiceDiscovered(PeerHandle, byte[], java.util.List) event.

Aware messages are not guaranteed delivery. Callbacks on DiscoverySessionCallback indicate message was transmitted successfully, onMessageSendSucceeded(int), or transmission failed (possibly after several retries) - onMessageSendFailed(int).

The peer will get a callback indicating a message was received using onMessageReceived(PeerHandle, byte[]).

Parameters
peerHandle PeerHandle: The peer's handle for the message. Must be a result of an onServiceDiscovered(PeerHandle, byte[], java.util.List) or onMessageReceived(PeerHandle, byte[]) events.

This value must never be null.

messageId int: An arbitrary integer used by the caller to identify the message. The same integer ID will be returned in the callbacks indicating message send success or failure. The messageId is not used internally by the Aware service - it can be arbitrary and non-unique.

message byte: The message to be transmitted.

This value may be null.