ConnectivityManager.NetworkCallback  |  API reference  |  Android Developers (original) (raw)

public static class ConnectivityManager.NetworkCallback
extends [Object](/reference/java/lang/Object) ``

Base class for NetworkRequest callbacks. Used for notifications about network changes. Should be extended by applications wanting notifications. A NetworkCallback is registered by calling[requestNetwork(NetworkRequest,NetworkCallback)](/reference/android/net/ConnectivityManager#requestNetwork%28android.net.NetworkRequest,%20android.net.ConnectivityManager.NetworkCallback%29),[registerNetworkCallback(NetworkRequest,NetworkCallback)](/reference/android/net/ConnectivityManager#registerNetworkCallback%28android.net.NetworkRequest,%20android.net.ConnectivityManager.NetworkCallback%29), or [registerDefaultNetworkCallback(NetworkCallback)](/reference/android/net/ConnectivityManager#registerDefaultNetworkCallback%28android.net.ConnectivityManager.NetworkCallback%29). A NetworkCallback is unregistered by calling [unregisterNetworkCallback(NetworkCallback)](/reference/android/net/ConnectivityManager#unregisterNetworkCallback%28android.net.ConnectivityManager.NetworkCallback%29). 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 onReserved(NetworkCapabilities networkCapabilities) Called when a network is reserved.
void onUnavailable() If the callback was registered with one of the requestNetwork methods, this will be called if no network is found within the timeout specified in requestNetwork(NetworkRequest,NetworkCallback,int) call or if the requested network request cannot be fulfilled (whether or not a timeout was specified).
Inherited methods
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. finalClass<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Constants

FLAG_INCLUDE_LOCATION_INFO

public static final int FLAG_INCLUDE_LOCATION_INFO

Inclusion of this flag means location-sensitive redaction requests keeping location info. Some objects like [NetworkCapabilities](/reference/android/net/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](/reference/android/net/NetworkCapabilities) sent via [onCapabilitiesChanged(Network,NetworkCapabilities)](/reference/android/net/ConnectivityManager.NetworkCallback#onCapabilitiesChanged%28android.net.Network,%20android.net.NetworkCapabilities%29).

These include:

Note:

Public constructors

NetworkCallback

public NetworkCallback ()

NetworkCallback

public NetworkCallback (int flags)

Parameters
flags int: Value is either 0 or a combination of the following: FLAG_INCLUDE_LOCATION_INFO

Public methods

onAvailable

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)](/reference/android/net/ConnectivityManager#registerNetworkCallback%28android.net.NetworkRequest,%20android.app.PendingIntent%29), 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)](/reference/android/net/ConnectivityManager#requestNetwork%28android.net.NetworkRequest,%20android.app.PendingIntent%29) and[ConnectivityManager.registerDefaultNetworkCallback(NetworkCallback)](/reference/android/net/ConnectivityManager#registerDefaultNetworkCallback%28android.net.ConnectivityManager.NetworkCallback%29), 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](/reference/android/os/Build.VERSION%5FCODES#O), this will always immediately be followed by a call to [onCapabilitiesChanged(Network,NetworkCapabilities)](/reference/android/net/ConnectivityManager.NetworkCallback#onCapabilitiesChanged%28android.net.Network,%20android.net.NetworkCapabilities%29) then by a call to [onLinkPropertiesChanged(Network,LinkProperties)](/reference/android/net/ConnectivityManager.NetworkCallback#onLinkPropertiesChanged%28android.net.Network,%20android.net.LinkProperties%29), and a call to [onBlockedStatusChanged(Network,boolean)](/reference/android/net/ConnectivityManager.NetworkCallback#onBlockedStatusChanged%28android.net.Network,%20boolean%29).

Do NOT call [getNetworkCapabilities(Network)](/reference/android/net/ConnectivityManager#getNetworkCapabilities%28android.net.Network%29) or[getLinkProperties(Network)](/reference/android/net/ConnectivityManager#getLinkProperties%28android.net.Network%29) 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(Network,NetworkCapabilities)](/reference/android/net/ConnectivityManager.NetworkCallback#onCapabilitiesChanged%28android.net.Network,%20android.net.NetworkCapabilities%29) and[onLinkPropertiesChanged(Network,LinkProperties)](/reference/android/net/ConnectivityManager.NetworkCallback#onLinkPropertiesChanged%28android.net.Network,%20android.net.LinkProperties%29) 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

public void onBlockedStatusChanged (Network network, boolean blocked)

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

Do NOT call [getNetworkCapabilities(Network)](/reference/android/net/ConnectivityManager#getNetworkCapabilities%28android.net.Network%29) or[getLinkProperties(Network)](/reference/android/net/ConnectivityManager#getLinkProperties%28android.net.Network%29) 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

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](/reference/android/os/Build.VERSION%5FCODES#O) this method is guaranteed to be called immediately after [onAvailable(Network)](/reference/android/net/ConnectivityManager.NetworkCallback#onAvailable%28android.net.Network%29).

Do NOT call [getLinkProperties(Network)](/reference/android/net/ConnectivityManager#getLinkProperties%28android.net.Network%29) 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

public void onLinkPropertiesChanged (Network network, LinkProperties linkProperties)

Called when the network corresponding to this request changes [LinkProperties](/reference/android/net/LinkProperties).

Starting with [Build.VERSION_CODES.O](/reference/android/os/Build.VERSION%5FCODES#O) this method is guaranteed to be called immediately after [onAvailable(Network)](/reference/android/net/ConnectivityManager.NetworkCallback#onAvailable%28android.net.Network%29).

Do NOT call [getNetworkCapabilities(Network)](/reference/android/net/ConnectivityManager#getNetworkCapabilities%28android.net.Network%29) 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

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](/reference/android/net/ConnectivityManager.NetworkCallback#onAvailable%28android.net.Network%29) call with the new replacement network for graceful handover. This method is not guaranteed to be called before [NetworkCallback.onLost](/reference/android/net/ConnectivityManager.NetworkCallback#onLost%28android.net.Network%29) is called, for example in case a network is suddenly disconnected.

Do NOT call [getNetworkCapabilities(Network)](/reference/android/net/ConnectivityManager#getNetworkCapabilities%28android.net.Network%29) or[getLinkProperties(Network)](/reference/android/net/ConnectivityManager#getLinkProperties%28android.net.Network%29) 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

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 [getNetworkCapabilities(Network)](/reference/android/net/ConnectivityManager#getNetworkCapabilities%28android.net.Network%29) or[getLinkProperties(Network)](/reference/android/net/ConnectivityManager#getLinkProperties%28android.net.Network%29) 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.

onReserved

public void onReserved (NetworkCapabilities networkCapabilities)

Called when a network is reserved. The reservation includes the [NetworkCapabilities](/reference/android/net/NetworkCapabilities) that uniquely describe the network that was reserved. the caller communicates this information to hardware or software components on or off-device to instruct them to create a network matching this reservation.[onReserved(NetworkCapabilities)](/reference/android/net/ConnectivityManager.NetworkCallback#onReserved%28android.net.NetworkCapabilities%29) is called at most once and is guaranteed to be called before any other callback unless the reservation is unavailable. Once a reservation is made, the reserved [NetworkCapabilities](/reference/android/net/NetworkCapabilities) will not be updated, and the reservation remains in place until the reserved network connects or [onUnavailable()](/reference/android/net/ConnectivityManager.NetworkCallback#onUnavailable%28%29) is called.

Parameters
networkCapabilities NetworkCapabilities: The NetworkCapabilities of the reservation. This value cannot be null.

onUnavailable

public void onUnavailable ()

If the callback was registered with one of the requestNetwork methods, this will be called if no network is found within the timeout specified in [requestNetwork(NetworkRequest,NetworkCallback,int)](/reference/android/net/ConnectivityManager#requestNetwork%28android.net.NetworkRequest,%20android.net.ConnectivityManager.NetworkCallback,%20int%29) call or if the requested network request cannot be fulfilled (whether or not a timeout was specified). If the callback was registered when reserving a network, this method indicates that the reservation is removed. It can be called when the reservation is requested, because the system could not satisfy the reservation, or after the reserved network connects. When this callback is invoked the associated [NetworkRequest](/reference/android/net/NetworkRequest) will have already been removed and released, as if [unregisterNetworkCallback(NetworkCallback)](/reference/android/net/ConnectivityManager#unregisterNetworkCallback%28android.net.ConnectivityManager.NetworkCallback%29) had been called.