I came across registerDefaultNetworkCallback and registerNetworkCallback while updating my Android app for API 28.
Having reviewed the documentation, I cannot find the difference between registering a network callback and registering a default network callback.
When will one use which?
Thanks in advance :)
As far as I understood, the difference between registerDefaultNetworkCallback and registerNetworkCallback it's only based on customisation.
registerDefaultNetworkCallback works (surprisingly) as a default network listener, while registerNetworkCallback it's more configurable. For example:
val connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val builder = NetworkRequest.Builder()
builder.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
val networkRequest = builder.build()
connectivityManager.registerNetworkCallback(networkRequest,
object : ConnectivityManager.NetworkCallback () {
override fun onAvailable(network: Network?) {
super.onAvailable(network)
Log.i("Test", "Network Available")
}
override fun onLost(network: Network?) {
super.onLost(network)
Log.i("Test", "Connection lost")
}
})
Here onAvailable will be called only if the user connects to a cellular network (by connecting to WiFi it won't log anything). The same does onLost when disconnecting from cellular network.
If we do it like this:
connectivityManager.registerDefaultNetworkCallback(object : ConnectivityManager.NetworkCallback() {
override fun onAvailable(network: Network?) {
super.onAvailable(network)
Log.i("Test", "Default -> Network Available")
}
override fun onLost(network: Network?) {
super.onLost(network)
Log.i("Test", "Default -> Connection lost")
}
})
Both functions work as default callbacks when the user is connecting (or disconnecting) to/from a network (it can be either WiFi or cellular).
These are just some very basic examples. Of course NetworkRequest can have a lot of configurations by setting its capability or transportType. You can read more about these in the official documentation of NetworkRequest.
As far I've understood, and aside of the information provided by @MihaiV , there's another difference between them.
ConnectivityManager.registerDefaultNetworkCallback() was added in API 24 (or 26, depending if you use it along a Handler).
And ConnectivityManager.registerNetworkCallback() was added in API 21 (or API 23 if used along a NetworkRequest.
