如何在Android中检测WiFi接入点是否刚刚失去互联网连接

Question

I was looking for a way to react a case when:

• I am connected to WiFi
• the access point has just lost internet connection (eg the cable from router has been removed)

In such cases, Android phones or notebooks are notified about that state and showing exclamation mark next to the WiFi icon.

Is it possible to be notified about that state in Android API? I was looking in the documentation but not found any.

IMPORTANT NOTE: I am not looking for just checking internet connection manually or just listen for changing network connection status as I will not be notified when the WiFi access point that I am connected to has lost the connection.

So regarding above I was trying to just check the changes of the network connection, but as i explained it is not enough for my case:

override fun onReceive(context: Context, intent: Intent) {
val wifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, 
DEFAULT_WIFI_STATE_VALUE)
wifiStateSubject.onNext(wifiState)
Timber.d("Current wifi state: $wifiState")
}

Answer 1

You can periodically try to access some resource with low ping and low timeout rate and if it throws some kind of NetworkException you can suppose that connection not available.

UPD:

You can use or inspect this library https://github.com/pwittchen/NetworkEvents