Kotlin Network Change Listener for Android

If you're developing an Android app that requires internet connectivity, it's important to be able to detect changes in network connectivity to handle them accordingly. In Kotlin, you can use the NetworkCallback class to listen for changes in network connectivity and take action as needed.

Creating a Network Change Listener:

To create a network change listener, you need to create an instance of the ConnectivityManager.NetworkCallback class and override its methods. Below is an example:

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

val networkCallback = object : ConnectivityManager.NetworkCallback() {
    override fun onAvailable(network: Network) {
        // Do something when network is available
    }

    override fun onLost(network: Network) {
        // Do something when network is lost
    }

    override fun onUnavailable() {
        // Do something when network is unavailable
    }
}

connectivityManager.registerDefaultNetworkCallback(networkCallback)

In the above example, we first get an instance of the ConnectivityManager system service using the Context.getSystemService() method. We then create an instance of the ConnectivityManager.NetworkCallback class and override its methods to handle the network changes.

Finally, we register the network callback using the ConnectivityManager.registerDefaultNetworkCallback() method to start listening for network changes.

Handling Internet Connectivity Changes:

Once you have registered the network callback, you can take appropriate action based on the changes in network connectivity. For example, you may want to show a message to the user if the network is lost or resumed.

val networkCallback = object : ConnectivityManager.NetworkCallback() {
    override fun onAvailable(network: Network) {
        // Do something when network is available
    }

    override fun onLost(network: Network) {
        showToast("Internet connection lost")
    }

    override fun onUnavailable() {
        showToast("Internet connection unavailable")
    }
}

fun showToast(message: String) {
    Toast.makeText(context, message, Toast.LENGTH_SHORT).show()
}

In the example above, we show a toast message when the internet connection is lost or unavailable.

Conclusion:

In this tutorial, we discussed how to create a network change listener using ConnectivityManager.NetworkCallback class in Kotlin for Android app development. By detecting changes in network connectivity, you can ensure that your app functions smoothly even when the user's network connection changes.