I am building an app which requires an access point to be enabled throughout... how can i get an interrupt or notification whenever the access point gets disabled...?
Do you need a WIFI connection or any connection at all? This will trigger when wifi drops:
SUPPLICANT_CONNECTION_CHANGE_ACTION
Related
The moment I get on a wifi connection, the cellular network is completely lost even though the cellular network indicator is definitely on.
This is my network request
val request = NetworkRequest.Builder().run {
addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
build()
}
connectivityManager.registerNetworkCallback(request, callback)
I've tried looking in the connectivityManager.allNetworks list and it's no where to be found. Only the wifi network is in there.
What's even weirder is there is one other cellular network that is always there. It does not have the same ID as my cellular network. There's no connection that can be made with it. It never shows up with registerNetworkCallback. The capabilities on it always include "valid" and "internet"
What am I seeing here? Why is my cellular network lost? What is this phantom cellular network?
targetSdkVersion: 29
Device: Galaxy S10 - Android 12
I figured this out.
If you call registerNetworkCallback the above will happen, but if you call requestNetwork with TRANSPORT_CELLULAR,
connectivityManager.requestNetwork(request, callback)
Android will keep the cellular network around. I was so confused because the documentation was so lacking. Once you do that, it will ask you to add the CHANGE_NETWORK_STATE permission.
After this step, the network is available, but you won't be able to make any request with it. You have to call
connectivityManager.bindProcessToNetwork(theCellularNetwork)
to get any connection.
After this is done, the cellular network can be used in tandem with the wifi network. You can even send some traffic to one and some to the other. If you use OkHttp like I do, you just bind the client with the network's socketFactory
val client = OkHttpClient().newBuilder().run {
socketFactory(network.socketFactory)
build()
}
client.newCall(
Request.Builder().url("https://example.com").build()
).execute().let {
Log.i(TAG, "Fetched ${it.body!!.string()}")
}
The cellular network isn't lost, but your app isn't allowed to use it. Once WiFi is connected, everything is forced to use that connection. The only exception to this rule is if your phone has a feature called "Dual Acceleration", which allows the cellular connection to stay active (and obviously, the user would have to enable that feature). Alternatively, you may have a setting in your phone's Developer Options called "Cellular Data Always Active", which will do the same thing.
But needless to say, you can't rely on either of those 2 features being enabled in a production environment. So, just assume that when WiFi is connected, that's the only connection that your app can use
Can I from my application force android to reconnect to cellular network immediately?
If yes how to do this?
Apparently the functionality as of Android 5 has been moved to system apps only. How to enable mobile data on/off programmatically
But you can still register a listener for network changes.
https://developer.android.com/training/basics/network-ops/reading-network-state
When you get the onLost() event you can start a Wireless Setting Activity so the user can do it manually.
//As seen in the link above.
Intent intent = new Intent(Settings.ACTION_WIRELESS_SETTINGS);
startActivity(intent);
This will be a common occurrence so get use to it. For example you can createBond() for a Bluetooth device, but you can't removeBond() anymore. Thus you have to send the user to the Bluetooth setting activity for the user to
"forget" about the device.
I have an Android VPN application. When I fire the intent to start the VPN (via VPNService.prepare), it fails immediately if there's an always-on VPN already configured on the device. That seems reasonable, but I'd like to be able to easily detect that case, so I can show a helpful message to the user.
By 'always on' I mean the specific VPN always-on Android VPN flag: https://developer.android.com/guide/topics/connectivity/vpn#always-on
I can't seem to find a way to access that info, even though it is used internally in Android (e.g. here but that getAlwaysOnVpnPackage doesn't seem to be available publicly AFAICT).
The best option I've seen is Check if a VPN connection is active in Android?, which will tell you if any VPN connection is currently active, but that's not enough, because:
I don't want to know about temporary VPN connections: I'm only interested if it's an always-on VPN connection.
Sometimes 'always-on' connections aren't actually always on. If you have a disconnected connection and set it as 'always-on', it's configured as such, and blocks all other VPN installs, but there's no network connection created (Android shows a persistent warning instead, which takes you to the other app to activate the connection). Because there's no connection, the above technique doesn't work. I still need to detect this case, since it still blocks my VPN setup.
Is there any way to check whether the device currently has a VPN configured as 'always-on'?
You can use this method
private fun isVpnAlwaysOn(): Boolean {
return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
val alwaysOn = Settings.Secure.getString(contentResolver, "always_on_vpn_app")
return !alwaysOn.isNullOrEmpty()
} else false
}
'alwaysOn' contains the package name of the app for which always-on is configured.
In the end, it seems this isn't possible on a normal device any way that I can find. I think is possible if you're a device admin, but that requires managed enterprise devices etc.
For now, I've handled this by watching for near-instant (less than 200ms) VPN setup failures (between running startActivityForResult(vpnIntent) and receiving onActivityResult with RESULT_CANCELED) and then showing a helpful message in that case.
Full implementation is in https://github.com/httptoolkit/httptoolkit-android/commit/928fbf92a4f868042789471be0d42800a226194b in case you're trying to do the same.
I am tring to setup WIFI P2P on 2 devices using
manager.addLocalService(channel, service, ActionListener)
and then connect both devices using
manager.connect(channel, config, ActionListener).
I would like to know which method is called before the popup to accept/reject connection is shown on the target device. All I was able to find was onConnectionInfoAvailable(WifiP2pInfo p2pInfo), but it is called after the connection is established.
I basically want to receive the "instance name" of the device trying to connect to me using WIFI P2P and then reject the connection request without showing system dialog(that allows the user to accept/reject connection).
I can't anything that can help me do this on docs or any other place. If anyone knows how to do it or can point me in the right direction then please let me know.
I solved it. I can put the instancename and devicename (of device I want to connect to) in Map that is passed when setting up service. From other device I can retrieve map of all devices available using this and find the instancename of one I need.
I know there are a few threads on this topic but non of them seem to answer my question. I want to be able to detect when the device has no data connection. I have tried the NetworkInfo route checking if its null, isConnected(), isAvailable() etc. The problem im having is that these work fine (return false or null) when wifi or mobile network are disabled however when they are enabled but there is no signal they return true. Is there any way to detect no data connection due to no signal?
build reciver and catch broadcast
Intent action for network events in android sdk
You could try pinging google.com. If there's no response, you can be fairly sure that there's no connection (unless the user is in a country where it is blocked).
I use ConnectivityManager.getActiveNetworkInfo.isConnectedOrConnecting()
I just tested it 5 minutes ago to make sure, and if everything is working and I then walk away from my house until my router is no longer within range and the network strength indicator on the status bar shows no network, a call to isConnectedOrConnecting() from within an app returns false.
I take it that's not the behavior you are seeing?