Develop Reference

ConnectivityManager only can detect connectivity but not network availability

The code below is used to detect network connectivity. The scenario is the software connected to the phone's hotspot but the phone's cellular network doesn't switch on. The code below return isConnected = true, which means it is only detects connectivity? The question is how I change it to detect network availability?
fun Context.isOnline(): Boolean {
val connectivityManager =
this.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val networkInfo = connectivityManager.activeNetworkInfo
if (networkInfo == null) {
log(message = "Network info is **NULL**")
return false
} else {
val isConnected = when(networkInfo.detailedState) {
NetworkInfo.DetailedState.CONNECTING -> true
NetworkInfo.DetailedState.AUTHENTICATING -> true
NetworkInfo.DetailedState.OBTAINING_IPADDR -> true
NetworkInfo.DetailedState.CONNECTED -> true
NetworkInfo.DetailedState.VERIFYING_POOR_LINK -> true
else -> false
}
if (!isConnected) {
log(message = "Network state is **${networkInfo.detailedState?.name ?: "NULL"}**")
}
return isConnected
}
}

You're using a deprecated API with NetworkInfo. You should be using NetworkCapabilities.NET_CAPABILITY_VALIDATED
Indicates that connectivity on this network was successfully validated. For example, for a network with NET_CAPABILITY_INTERNET, it means that Internet connectivity was successfully detected.
SDK >= 23
You could change your code to something like this to see if that's true to confirm internet connectivity:
connectivityManager
.getNetworkCapabilities(connectivityManager.getActiveNetwork())
.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
SDK >= 21
If you are using anything as old as SDK 21, you can use the ConnectivityManager.registerNetworkCallback API.
boolean isConnected = false;
final NetworkRequest request =
new NetworkRequest.Builder()
.addCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
.build();
final ConnectivityManager connectivityManager = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkCallback networkCallback = new NetworkCallback() {
#Override
void onAvailable(Network network) {
// Triggers when this network is available.
isConnected = true;
}
#Override
void onLost(Network network) {
// Triggers when this network is lost.
isConnected = false;
}
};
connectivityManager.requestNetwork(request, networkCallback);

App crashes when no internet during Retrofit2 Get request

My application seems to keep crashing giving me an E/AndroidRuntime: FATAL EXCEPTION: main error when i try to make a Get request to a server and there is no internet. I expected the app to run but no data be displayed.
Log.i("getStoreData()" , "Inside the coroutine before getData")
this is the last log that I have put myself gets printed before the app crashes.
private fun getStoreData() {
Log.i("getStoreData()", " inside getStoreData")
val job = coroutineScope.launch {
Log.i("getStoreData()" , "Inside the coroutine before getData")
var data = StoreAPI.retrofitService.getData()
Log.i("getStoreData()" , "Inside the coroutine after getData")
try {
var storeData = data.stores
_status.value = "Success: ${storeData.size} Stores received"
if(storeData.size > 0){
_stores.value = storeData
}
} catch (t: Throwable) {
Log.i("Retrofit catch block", _status.value)
_status.value = "Failure: " + t.message
t.printStackTrace()
}
}
}
StoreAPIService.kt
private const val URL = "http://sandbox.bottlerocketapps.com/BR_Android_CodingExam_2015_Server/"
private val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
private val retrofit = Retrofit.Builder()
.addConverterFactory(MoshiConverterFactory.create(moshi))
.baseUrl(URL)
.build()
interface StoreAPIService{
//Initially was using Jake Wharton's library for retrofit2 kotlin coroutines support but it has been deprecated since the support
// addition of the suspend keyword in retrofit 2.6.0
//Suspend does all the task of coroutines for us by just adding it before the function declaration
#GET("stores.json")
suspend fun getData():
Data //return Data object because Data has access to the Store JSON Object/Array
}
object StoreAPI{
val retrofitService: StoreAPIService by lazy {
retrofit.create(StoreAPIService::class.java)
}
}
Any idea why?
EDIT:
I cannot use these network connectivity functions because I my fragment is not connected to any activity and the fragment is connected to a viewModel. Therefore this line of code doesn't work as there is no context to bound it to. If you have a work around for this that would be great too.
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

NB: before making any Network call or sending any requesting you must ensure that the device is connected to internet. I entice you to write a simple function to check if you're connected, if you're connected then you can send the request or make a network call.

Try using this
Create Class For NetworkConnectionDetection
Manifest
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
NetworkConnection Class
class NetworkConnection(val context: Context) : LiveData<Boolean>() {
var connectionManger: ConnectivityManager =
context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
lateinit var netwrokCallback: ConnectivityManager.NetworkCallback
override fun onActive() {
super.onActive()
updateConnection()
when {
Build.VERSION.SDK_INT >= Build.VERSION_CODES.N -> {
connectionManger.registerDefaultNetworkCallback(NetworkConnectioncallback())
}
Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP -> {
lollipopNetworkRequest()
}
else -> {
context.registerReceiver(
networkReciever(),
IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
)
}
}
}
/*override fun onInactive() {
super.onInactive()
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
connectionManger.unregisterNetworkCallback(NetworkConnectioncallback())
} else {
context.unregisterReceiver(networkReciever())
}
}*/
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
fun lollipopNetworkRequest() {
val requestBuilder = NetworkRequest.Builder()
.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.addTransportType(NetworkCapabilities.TRANSPORT_ETHERNET)
connectionManger.registerNetworkCallback(
requestBuilder.build(),
NetworkConnectioncallback()
)
}
fun NetworkConnectioncallback(): ConnectivityManager.NetworkCallback {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
netwrokCallback = object : ConnectivityManager.NetworkCallback() {
override fun onLost(network: Network) {
super.onLost(network)
postValue(false)
}
override fun onAvailable(network: Network) {
super.onAvailable(network)
postValue(true)
}
}
return netwrokCallback
} else {
throw IllegalAccessError("Error!")
}
}
fun networkReciever() = object : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
updateConnection()
}
}
fun updateConnection() {
val activeNetwork: NetworkInfo? = connectionManger.activeNetworkInfo
postValue((activeNetwork?.isConnected == true))
}
}
Now Inside your Activity/Fragment Check the connection either it is connected or not. Here is how it will be achieved
val networkConnection = NetworkConnection(requireContext())
networkConnection.observe(viewLifecycleOwner, { isConnected ->
if (isConnected) {
// Do what ever you want to do
} else {
// Show No internet connection message
}
})

You need to add internet checks before calling your retrofit service because to get some data from server, internet connectivity is mandatory

This method checks whether mobile is connected to internet and returns true
if connected:
private boolean isNetworkConnected() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected();
}
in manifest,
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
Edit: This method actually checks if device is connected to internet(There is
a possibility it's connected to a network but not to internet).
public boolean isInternetAvailable() {
try {
InetAddress ipAddr = InetAddress.getByName("google.com");
//You can replace it with your name
return !ipAddr.equals("");
}catch (Exception e) {
return false;
}
}

This will tell you if you're connected to a network:
boolean connected = false;
ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
//we are connected to a network
connected = true;
}
else
connected = false;

I also followed that tutorial, but I don't remember it having an offline mode. That is an option that you have to integrate on yourself.
When you create the viewModel, because it has an init block, it makes the call to the API and if you don't have an Internet connection, it crashes.
So you should write the init viewModel some code that checks whether you have an Internet connection or not. Or in the method that makes the API call to get the data.
In the next lesson from that tutorial, "Behind the scenes", they talk about offline mode.

Check internet connection with target sdk 29 and without deprecated methods

I have the
compileSdkVersion 29
and
targetSdkVersion 29
in my android app. And to check if there is a connection I use the next code:
val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager?
return connectivityManager?.activeNetworkInfo?.isConnected ?: false
But with my targetSdk the activeNetworkInfo is deprecated. How can I check the connection status without deprecated methods and variables?

You can do it as below:
val connectivityManager =
context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
val network = connectivityManager.activeNetwork
val capabilities = connectivityManager.getNetworkCapabilities(network)
return capabilities != null && (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) || capabilities.hasTransport(
NetworkCapabilities.TRANSPORT_CELLULAR
))
}

Use ConnectivityManager.NetworkCallback instead, here is the link for documentation

getActiveNetworkInfo() is deprecated in API 29 [duplicate]

This question already has answers here:
activeNetworkInfo.type is deprecated in API level 28
(16 answers)
Closed 3 years ago.
I am using a code that check if user has internet active or not but after targeting sdk29 the functions bellow became deprecated
NetworkInfo
NetworkInfo.isConnected()
getActiveNetworkInfo()
Here is the code :
public static boolean isNetworkAvailable(Context context) {
if(context == null) { return false; }
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
// if no network is available networkInfo will be null, otherwise check if we are connected
try {
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
if (activeNetworkInfo != null && activeNetworkInfo.isConnected()) {
Log.i("update_statut","Network is available : true");
return true;
}
} catch (Exception e) {
Log.i("update_statut",""+ e.getMessage());
}
Log.i("update_statut","Network is available : FALSE ");
return false;
}

It's deprecated base on Google Document
getActiveNetworkInfo is deprecated on API 29.
getAllNetworkInfo is deprecated on API 23.
So, If you want to find the Network Connection status, you can use this code.
kotlin :
private fun isNetworkAvailable(context: Context): Boolean {
val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val nw = connectivityManager.activeNetwork ?: return false
val actNw = connectivityManager.getNetworkCapabilities(nw) ?: return false
return when {
actNw.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
actNw.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
//for other device how are able to connect with Ethernet
actNw.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
//for check internet over Bluetooth
actNw.hasTransport(NetworkCapabilities.TRANSPORT_BLUETOOTH) -> true
else -> false
}
} else {
val nwInfo = connectivityManager.activeNetworkInfo ?: return false
return nwInfo.isConnected
}
}
Java :
private Boolean isNetworkAvailable(Application application) {
ConnectivityManager connectivityManager = (ConnectivityManager) application.getSystemService(Context.CONNECTIVITY_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
Network nw = connectivityManager.getActiveNetwork();
if (nw == null) return false;
NetworkCapabilities actNw = connectivityManager.getNetworkCapabilities(nw);
return actNw != null && (actNw.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) || actNw.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) || actNw.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) || actNw.hasTransport(NetworkCapabilities.TRANSPORT_BLUETOOTH));
} else {
NetworkInfo nwInfo = connectivityManager.getActiveNetworkInfo();
return nwInfo != null && nwInfo.isConnected();
}
}
you can see all NetworkCapability here.

I have finally found a code that works on all APIs in case anybody want it
NetworkCapabilities is not deprecated in API 29 but it requires API 21 so I have called it on API 29 only.
However getActiveNetworkInfo() is deprecated only in API 29 and works on all APIs , so we can use it in all apis bellow 29
here's the code
public static boolean isNetworkAvailable(Context context) {
if(context == null) return false;
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivityManager != null) {
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(connectivityManager.getActiveNetwork());
if (capabilities != null) {
if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
return true;
} else if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_WIFI)) {
return true;
} else if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET)){
return true;
}
}
}
else {
try {
NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
if (activeNetworkInfo != null && activeNetworkInfo.isConnected()) {
Log.i("update_statut", "Network is available : true");
return true;
}
} catch (Exception e) {
Log.i("update_statut", "" + e.getMessage());
}
}
}
Log.i("update_statut","Network is available : FALSE ");
return false;
}

You can find all the info in the official doc
This class was deprecated in API level 29.
Callers should instead use the ConnectivityManager.NetworkCallback API to learn about connectivity changes, or switch to use ConnectivityManager#getNetworkCapabilities or ConnectivityManager#getLinkProperties to get information synchronously. Keep in m`ind that while callbacks are guaranteed to be called for every event in order, synchronous calls have no such constraints, and as such it is unadvisable to use the synchronous methods inside the callbacks as they will often not offer a view of networking that is consistent (that is: they may return a past or a future state with respect to the event being processed by the callback). Instead, callers are advised to only use the arguments of the callbacks, possibly memorizing the specific bits of information they need to keep from one callback to another.
You can use something like:
if (connectivityManager != null) {
if (if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
NetworkCapabilities capabilities = connectivityManager.getNetworkCapabilities(connectivityManager.getActiveNetwork());
if (capabilities != null) {
if (capabilities.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR)) {
//...
}
}
} else {
// current code
}
}

Force Android to Use Wifi network with no internet

I am building an android app that needs to communicate over a WiFi network that will not have any internet access. The problem is that even when the WiFi is connected android chooses to use cellular/mobile data when no connection internet is present on the wifi network.
I have read many posts on the issue many of which involve rooting the device but that is not possible with a production app (rooting devices is not an option). other solution (like my code bellow) suggest using bindProcessToNetwork() which works perfectly on my Sony Z2 but not on other devices I have tested on (all running 6.0.1)
private void bindToNetwork() {
final ConnectivityManager connectivityManager = (ConnectivityManager) mActivity.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkRequest.Builder builder;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
builder = new NetworkRequest.Builder();
//set the transport type do WIFI
builder.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
connectivityManager.requestNetwork(builder.build(), new ConnectivityManager.NetworkCallback() {
#Override
public void onAvailable(Network network) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
connectivityManager.bindProcessToNetwork(null);
if (barCodeData.getSsid().contains("ap-name")) {
connectivityManager.bindProcessToNetwork(network);
}
} else {
//This method was deprecated in API level 23
ConnectivityManager.setProcessDefaultNetwork(null);
if (barCodeData.getSsid().contains("ap-name")) {
ConnectivityManager.setProcessDefaultNetwork(network);
}
}
connectivityManager.unregisterNetworkCallback(this);
}
});
}
}

You can solve this by setting captive_portal_detection_enabled to 0 (false).
What's actually happening is that by default, everytime you connect to a wifi, the FW will test against a server (typically google) to see if it's a captive wifi (needs login). So if your wifi is not connected to google, this check will fail. After that, the device knows that wifi has no internet connection and simply will not autoconnect to it.
Setting this setting to 0 will avoid this check.
Programatically:
Settings.Global.putInt(getContentResolver(), Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED, 0);
Edit: You may need to use the string "captive_portal_detection_enabled" directly, instead of the constant that's not visible depending on Android version.

you'd need to disable mobile data in the Settings (not certain, if this can be done programmatically, which might be a possible option) - or take out the USIM;
else the common behavior is, that it will always fall back to the best available connection (while a connection with internet gateway might be preferred, because it is used by most application).
also see this answer.

Solution on Kotlin
class ConnectWithoutInternetTest constructor(
private val mContext: Context,
private val connectivityManager: ConnectivityManager,
private val wifiManager: WifiManager
) {
private val mWifiBroadcastReceiver = object : BroadcastReceiver() {
override fun onReceive(context: Context, intent: Intent) {
when (intent.action) {
WifiManager.NETWORK_STATE_CHANGED_ACTION -> {
val info = intent.getParcelableExtra<NetworkInfo>(WifiManager.EXTRA_NETWORK_INFO)
val isConnected = info.isConnected
val ssid: String? = normalizeAndroidWifiSsid(wifiManager.connectionInfo?.ssid)
if (isConnected) {
val builder = NetworkRequest.Builder()
builder.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
connectivityManager.registerNetworkCallback(
builder.build(),
object : ConnectivityManager.NetworkCallback() {
override fun onAvailable(network: Network) {
super.onAvailable(network)
val networkInfo = connectivityManager.getNetworkInfo(network)
val networkSsid = networkInfo.extraInfo
if (networkSsid == ssid) {
connectivityManager.unregisterNetworkCallback(this)
}
}
})
}
}
}
}
}
private fun init() {
val intentFilter = IntentFilter()
intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION)
mContext.registerReceiver(mWifiBroadcastReceiver, intentFilter)
}
private fun destroy() {
mContext.unregisterReceiver(mWifiBroadcastReceiver)
}
private fun normalizeAndroidWifiSsid(ssid: String?): String? {
return ssid?.replace("\"", "") ?: ssid
}
fun connectToWifi(ssidParam: String, password: String?) {
init()
val ssid = "\"$ssidParam\""
val config = wifiManager.configuredNetworks.find { it.SSID == ssid }
val netId = if (config != null) {
config.networkId
} else {
val wifiConfig = WifiConfiguration()
wifiConfig.SSID = ssid
password?.let { wifiConfig.preSharedKey = "\"$password\"" }
wifiConfig.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE)
wifiManager.addNetwork(wifiConfig)
}
wifiManager.disconnect()
val successful = wifiManager.enableNetwork(netId, true)
}

You're in the right path, the solution is indeed with ConnectivityManager.bindProcessToNetwork(network). This information was posted on the Android Developers Blog in this article: Connecting your App to a Wi-Fi Device.
Looking into your code this barCodeData.getSsid() doesn't look that is getting the SSID of the currently connected wifi network. If that's the case your code will never successfully bind to the network.
Try replace your if statement
if (barCodeData.getSsid().contains("ap-name"))
With
if (getNetworkSsid(context).equals("ap-name"))
Helper method in kotlin to retrieve the SSID of the connected wifi network
private fun getNetworkSsid(context: Context?): String {
// WiFiManager must use application context (not activity context) otherwise a memory leak can occur
val mWifiManager = context?.applicationContext?.getSystemService(Context.WIFI_SERVICE) as WifiManager
val wifiInfo: WifiInfo? = mWifiManager.connectionInfo
if (wifiInfo?.supplicantState == SupplicantState.COMPLETED) {
return wifiInfo.ssid.removeSurrounding("\"")
}
return ""
}
If still doesn't work please follow my complete solution where I used the same method but with some extra checks. I tested it in the Android versions 5.1.1, 6.0, 6.0.1, 7.1.1 and 8.1.0.

You're on the right path, you only need to tweak what you have a bit. One of the main issues I see is that you unregister the network callback on onAvailable() which is not a good idea as networks tend to switch between available/unavailable from time-to-time which would cause issues on your device.
The other thing to consider is requesting a network that's Wi-Fi and clearing the other network capabilities as they may cause you issues depending on your network's setup.
Here is another version of how to do that which is hopefully a bit simpler.
final NetworkRequest requestForWifi =
new NetworkRequest.Builder()
.clearCapabilities() // We only care about Wi-Fi
.addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
.build();
final ConnectivityManager connectivityManager = (ConnectivityManager)
context.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkCallback networkCallbackWifi = new NetworkCallback() {
#Override
void onAvailable(Network network) {
// Once this callback triggers, a Wi-Fi network is available
WifiInfo wifiInfo = connectivity.getNetworkCapabilities(network).TransportInfo;
string ssid = wifiInfo.SSID.Trim(new char[] {'"', '\"' });
if (!ssid.contains("ap-name")) {
return;
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
connectivityManager.bindProcessToNetwork(network);
} else {
ConnectivityManager.setProcessDefaultNetwork(network);
}
}
};
// Last thing is to actually request a network.
connectivityManager.requestNetwork(requestForWifi, networkCallbackWifi);

You can check if wifi is connected then proceed else show a dialog to user asking him to connect to a wifi network
Since the method NetworkInfo.isConnected() is now deprecated in API-23, here is a method which detects if the Wi-Fi adapter is on and also connected to an access point using WifiManager instead:
private boolean checkWifiOnAndConnected() {
WifiManager wifiMgr = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (wifiMgr.isWifiEnabled()) { // Wi-Fi adapter is ON
WifiInfo wifiInfo = wifiMgr.getConnectionInfo();
if( wifiInfo.getNetworkId() == -1 ){
return false; // Not connected to an access point
}
return true; // Connected to an access point
}
else {
return false; // Wi-Fi adapter is OFF
}
}