ConnectivityManager.NetworkCallback

public static class ConnectivityManager.NetworkCallback
extends Object

java.lang.Object
   ↳ android.net.ConnectivityManager.NetworkCallback


Base class for NetworkRequest callbacks. Used for notifications about network changes. Should be extended by applications wanting notifications. A NetworkCallback is registered by calling ConnectivityManager.requestNetwork(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback), ConnectivityManager.registerNetworkCallback(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback), or ConnectivityManager.registerDefaultNetworkCallback(android.net.ConnectivityManager.NetworkCallback). A NetworkCallback is unregistered by calling ConnectivityManager.unregisterNetworkCallback(android.net.ConnectivityManager.NetworkCallback). A NetworkCallback should be registered at most once at any time. A NetworkCallback that has been unregistered can be registered again.

Summary

Constants

int FLAG_INCLUDE_LOCATION_INFO

Inclusion of this flag means location-sensitive redaction requests keeping location info.

Public constructors

NetworkCallback()
NetworkCallback(int flags)

Public methods

void onAvailable(Network network)

Called when the framework connects and has declared a new network ready for use.

void onBlockedStatusChanged(Network network, boolean blocked)

Called when access to the specified network is blocked or unblocked.

void onCapabilitiesChanged(Network network, NetworkCapabilities networkCapabilities)

Called when the network corresponding to this request changes capabilities but still satisfies the requested criteria.

void onLinkPropertiesChanged(Network network, LinkProperties linkProperties)

Called when the network corresponding to this request changes LinkProperties.

void onLosing(Network network, int maxMsToLive)

Called when the network is about to be lost, typically because there are no outstanding requests left for it.

void onLost(Network network)

Called when a network disconnects or otherwise no longer satisfies this request or callback.

void onUnavailable()

Called if no network is found within the timeout time specified in ConnectivityManager.requestNetwork(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback, int) call or if the requested network request cannot be fulfilled (whether or not a timeout was specified).

Inherited methods

Constants

FLAG_INCLUDE_LOCATION_INFO

Added in API level 31
Also in U Extensions 1
public static final int FLAG_INCLUDE_LOCATION_INFO

Inclusion of this flag means location-sensitive redaction requests keeping location info. Some objects like NetworkCapabilities may contain location-sensitive information. Prior to Android 12, this information is always returned to apps holding the appropriate permission, possibly noting that the app has used location.

In Android 12 and above, by default the sent objects do not contain any location information, even if the app holds the necessary permissions, and the system does not take note of location usage by the app. Apps can request that location information is included, in which case the system will check location permission and the location toggle state, and take note of location usage by the app if any such information is returned. Use this flag to include any location sensitive data in NetworkCapabilities sent via onCapabilitiesChanged(android.net.Network, android.net.NetworkCapabilities).

These include:

  • Some transport info instances (retrieved via NetworkCapabilities#getTransportInfo()) like WifiInfo contain location sensitive information.
  • OwnerUid (retrieved via NetworkCapabilities#getOwnerUid() is location sensitive for wifi suggestor apps (i.e using WifiNetworkSuggestion).
  • Note:

  • Retrieving this location sensitive information (subject to app's location permissions) will be noted by system.
  • Without this flag any NetworkCapabilities provided via the callback does not include location sensitive information.

    Constant Value: 1 (0x00000001)

  • Public constructors

    NetworkCallback

    Added in API level 21
    Also in U Extensions 1
    public NetworkCallback ()

    NetworkCallback

    Added in API level 21
    Also in U Extensions 1
    public NetworkCallback (int flags)

    Parameters
    flags int: Value is either 0 or a combination of android.net.ConnectivityManager.NetworkCallback.FLAG_NONE, and FLAG_INCLUDE_LOCATION_INFO

    Public methods

    onAvailable

    Added in API level 21
    Also in U Extensions 1
    public void onAvailable (Network network)

    Called when the framework connects and has declared a new network ready for use.

    For callbacks registered with ConnectivityManager.registerNetworkCallback(NetworkRequest, PendingIntent), multiple networks may be available at the same time, and onAvailable will be called for each of these as they appear.

    For callbacks registered with ConnectivityManager.requestNetwork(NetworkRequest, PendingIntent) and ConnectivityManager.registerDefaultNetworkCallback(NetworkCallback), this means the network passed as an argument is the new best network for this request and is now tracked by this callback ; this callback will no longer receive method calls about other networks that may have been passed to this method previously. The previously-best network may have disconnected, or it may still be around and the newly-best network may simply be better.

    Starting with Build.VERSION_CODES.O, this will always immediately be followed by a call to onCapabilitiesChanged(android.net.Network, android.net.NetworkCapabilities) then by a call to onLinkPropertiesChanged(android.net.Network, android.net.LinkProperties), and a call to onBlockedStatusChanged(android.net.Network, boolean).

    Do NOT call ConnectivityManager.getNetworkCapabilities(android.net.Network) or ConnectivityManager.getLinkProperties(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions (there is no guarantee the objects returned by these methods will be current). Instead, wait for a call to onCapabilitiesChanged(android.net.Network, android.net.NetworkCapabilities) and onLinkPropertiesChanged(android.net.Network, android.net.LinkProperties) whose arguments are guaranteed to be well-ordered with respect to other callbacks.

    Parameters
    network Network: The Network of the satisfying network. This value cannot be null.

    onBlockedStatusChanged

    Added in API level 29
    Also in U Extensions 1
    public void onBlockedStatusChanged (Network network, 
                    boolean blocked)

    Called when access to the specified network is blocked or unblocked.

    Do NOT call ConnectivityManager.getNetworkCapabilities(android.net.Network) or ConnectivityManager.getLinkProperties(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions : calling these methods while in a callback may return an outdated or even a null object.

    Parameters
    network Network: The Network whose blocked status has changed. This value cannot be null.

    blocked boolean: The blocked status of this Network.

    onCapabilitiesChanged

    Added in API level 21
    Also in U Extensions 1
    public void onCapabilitiesChanged (Network network, 
                    NetworkCapabilities networkCapabilities)

    Called when the network corresponding to this request changes capabilities but still satisfies the requested criteria.

    Starting with Build.VERSION_CODES.O this method is guaranteed to be called immediately after onAvailable(Network).

    Do NOT call ConnectivityManager.getLinkProperties(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions : calling these methods while in a callback may return an outdated or even a null object.

    Parameters
    network Network: The Network whose capabilities have changed. This value cannot be null.

    networkCapabilities NetworkCapabilities: The new NetworkCapabilities for this network. This value cannot be null.

    onLinkPropertiesChanged

    Added in API level 21
    Also in U Extensions 1
    public void onLinkPropertiesChanged (Network network, 
                    LinkProperties linkProperties)

    Called when the network corresponding to this request changes LinkProperties.

    Starting with Build.VERSION_CODES.O this method is guaranteed to be called immediately after onAvailable(Network).

    Do NOT call ConnectivityManager.getNetworkCapabilities(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions : calling these methods while in a callback may return an outdated or even a null object.

    Parameters
    network Network: The Network whose link properties have changed. This value cannot be null.

    linkProperties LinkProperties: The new LinkProperties for this network. This value cannot be null.

    onLosing

    Added in API level 21
    Also in U Extensions 1
    public void onLosing (Network network, 
                    int maxMsToLive)

    Called when the network is about to be lost, typically because there are no outstanding requests left for it. This may be paired with a NetworkCallback#onAvailable call with the new replacement network for graceful handover. This method is not guaranteed to be called before NetworkCallback#onLost is called, for example in case a network is suddenly disconnected.

    Do NOT call ConnectivityManager.getNetworkCapabilities(android.net.Network) or ConnectivityManager.getLinkProperties(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions ; calling these methods while in a callback may return an outdated or even a null object.

    Parameters
    network Network: The Network that is about to be lost. This value cannot be null.

    maxMsToLive int: The time in milliseconds the system intends to keep the network connected for graceful handover; note that the network may still suffer a hard loss at any time.

    onLost

    Added in API level 21
    Also in U Extensions 1
    public void onLost (Network network)

    Called when a network disconnects or otherwise no longer satisfies this request or callback.

    If the callback was registered with requestNetwork() or registerDefaultNetworkCallback(), it will only be invoked against the last network returned by onAvailable() when that network is lost and no other network satisfies the criteria of the request.

    If the callback was registered with registerNetworkCallback() it will be called for each network which no longer satisfies the criteria of the callback.

    Do NOT call ConnectivityManager.getNetworkCapabilities(android.net.Network) or ConnectivityManager.getLinkProperties(android.net.Network) or other synchronous ConnectivityManager methods in this callback as this is prone to race conditions ; calling these methods while in a callback may return an outdated or even a null object.

    Parameters
    network Network: The Network lost. This value cannot be null.

    onUnavailable

    Added in API level 26
    Also in U Extensions 1
    public void onUnavailable ()

    Called if no network is found within the timeout time specified in ConnectivityManager.requestNetwork(android.net.NetworkRequest, android.net.ConnectivityManager.NetworkCallback, int) call or if the requested network request cannot be fulfilled (whether or not a timeout was specified). When this callback is invoked the associated NetworkRequest will have already been removed and released, as if ConnectivityManager.unregisterNetworkCallback(android.net.ConnectivityManager.NetworkCallback) had been called.