Kotlin: Checking network status using ConnectivityManager returns null if network disconnected. How come?

Question

I try to check the status of my network (connected or disconnected) using this function:

// Check Network status
private fun isNetworkAvailable(): Boolean {
    val connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE)
    return if (connectivityManager is ConnectivityManager) {
        val networkInfo = connectivityManager.activeNetworkInfo
        networkInfo.isConnected
    }
    else false
}

This gives me a java.lang.IllegalStateException: networkInfo must not be null - error when run with a disconnected network. Why? And how can I solve this?

Levi Moreira · Accepted Answer · 2018-04-13T15:14:34.313

17

According to the docs activeNetworkInfo might be null:

Returns details about the currently active default data network. When connected, this network is the default route for outgoing connections. You should always check isConnected() before initiating network traffic. This may return null when there is no default network.

To make sure it doesn't crash, just use this:

 private fun isNetworkAvailable(): Boolean {
        val connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE)
        return if (connectivityManager is ConnectivityManager) {
            val networkInfo: NetworkInfo? = connectivityManager.activeNetworkInfo
            networkInfo?.isConnected ?: false
        } else false
    }

edited Apr 13 '18 at 15:14

answered Apr 13 '18 at 15:07

Levi Moreira

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1

I incorrectly assumed that **.isConnected** would always return a Boolean. – CEO tech4lifeapps Apr 13 '18 at 15:56
1

networkInfo is deprecated. Check this for an update response: https://stackoverflow.com/questions/53532406/activenetworkinfo-type-is-deprecated-in-api-level-28 – MarMass Dec 21 '19 at 16:36

AliSh · Answer 2 · 2020-10-12T04:35:29.443

getActiveNetwork has been deprecated in API 29, so this is the best solution:

fun isInternetAvailable(context: Context): Boolean {
    var result = false
    val connectivityManager =
        context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        val networkCapabilities = connectivityManager.activeNetwork ?: return false
        val actNw =
            connectivityManager.getNetworkCapabilities(networkCapabilities) ?: return false
        result = when {
            actNw.hasTransport(NetworkCapabilities.TRANSPORT_WIFI) -> true
            actNw.hasTransport(NetworkCapabilities.TRANSPORT_CELLULAR) -> true
            actNw.hasTransport(NetworkCapabilities.TRANSPORT_ETHERNET) -> true
            else -> false
        }
    } else {
        connectivityManager.activeNetworkInfo?.run {
            result = when (type) {
                ConnectivityManager.TYPE_WIFI -> true
                ConnectivityManager.TYPE_MOBILE -> true
                ConnectivityManager.TYPE_ETHERNET -> true
                else -> false
            }

        }
    }
    return result
}

score 3 · Answer 3 · edited Sep 22 '20 at 04:07

Use this code, it will surely help

fun checkConnectivity(context: Context): Boolean {

        val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager

        val activeNetwork: NetworkInfo? = connectivityManager.activeNetworkInfo
    
        if(activeNetwork?.isConnected!=null){
            return activeNetwork.isConnected
        }
        else{
            return false
        }
    }

score 1 · Answer 4 · answered Aug 13 '19 at 14:32

One of the easiest way is, Add an extension to Context class like below,

val Context.isConnected: Boolean
get() {
    return (getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager)
        .activeNetworkInfo?.isConnected == true
}

Now you can use it in activity like,

 if (!isConnected) {
 // connection is not available...
 }

You can use this way in activity, fragment or anywhere within the context.

Kotlin: Checking network status using ConnectivityManager returns null if network disconnected. How come?

4 Answers4