1. implemented network state receiver

app/src/main/java/io/github/chronosx88/yggdrasil/MainActivity.kt

@@ -3,6 +3,8 @@ package io.github.chronosx88.yggdrasil
 import android.app.Activity
 import android.app.ActivityManager
 import android.content.*
+import android.net.ConnectivityManager
+import android.net.Network
 import android.net.VpnService
 import android.os.Build
 import android.os.Bundle
@@ -16,6 +18,7 @@ import dalvik.system.DexFile
 import io.github.chronosx88.yggdrasil.models.DNSInfo
 import io.github.chronosx88.yggdrasil.models.PeerInfo
 import io.github.chronosx88.yggdrasil.models.config.DNSInfoListAdapter
+import io.github.chronosx88.yggdrasil.models.config.NetworkUtils
 import io.github.chronosx88.yggdrasil.models.config.PeerInfoListAdapter
 import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.deserializePeerStringList2PeerInfoSet
 import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.deserializeStringList2DNSInfoSet
@@ -24,7 +27,6 @@ import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.deserializeS
 import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.deserializeStringSet2PeerInfoSet
 import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.serializeDNSInfoSet2StringList
 import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.serializePeerInfoSet2StringList
-import java.lang.reflect.Method
 import kotlin.concurrent.thread
 
 
@@ -65,7 +67,7 @@ class MainActivity : AppCompatActivity() {
 
     private var currentPeers = setOf<PeerInfo>()
     private var currentDNS = setOf<DNSInfo>()
-    private var meshPeersReceiver: BroadcastReceiver? = null
+    private var networkStateReceiver: BroadcastReceiver? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -141,6 +143,33 @@ class MainActivity : AppCompatActivity() {
             ipLayout.visibility = View.VISIBLE
             findViewById<TextView>(R.id.ip).text = address
         }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            val connectivityManager = this.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+            connectivityManager?.let {
+                it.registerDefaultNetworkCallback(object : ConnectivityManager.NetworkCallback() {
+                    override fun onAvailable(network: Network) {
+                        startVpn()
+                    }
+                    override fun onLost(network: Network?) {
+                        stopVpn()
+                    }
+                })
+            }
+        } else {
+            networkStateReceiver = object : BroadcastReceiver() {
+                override fun onReceive(context: Context, intent: Intent) {
+                    val status: Int = NetworkUtils.getConnectivityStatusString(context)
+                    Log.i(TAG, "Network state has been changed")
+                    if ("android.net.conn.CONNECTIVITY_CHANGE" == intent.action) {
+                        if (status == NetworkUtils.NETWORK_STATUS_NOT_CONNECTED) {
+                            stopVpn()
+                        } else {
+                            startVpn()
+                        }
+                    }
+                }
+            }
+        }
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
             val sourceDir: String = this.applicationInfo.sourceDir
             val dexFile = DexFile(sourceDir)
@@ -335,8 +364,8 @@ class MainActivity : AppCompatActivity() {
 
     override fun onDestroy() {
         super.onDestroy()
-        if (meshPeersReceiver != null){
+        if (networkStateReceiver != null){
-            unregisterReceiver(meshPeersReceiver);
+            unregisterReceiver(networkStateReceiver);
         }
     }
 

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/NetworkUtils.kt

@@ -0,0 +1,44 @@
+package io.github.chronosx88.yggdrasil.models.config
+
+import android.content.Context
+import android.net.ConnectivityManager
+
+
+class NetworkUtils {
+
+    companion object {
+
+        val TYPE_WIFI = 1
+        val TYPE_MOBILE = 2
+        val TYPE_NOT_CONNECTED = 0
+        val NETWORK_STATUS_NOT_CONNECTED = 0
+        val NETWORK_STATUS_WIFI = 1
+        val NETWORK_STATUS_MOBILE = 2
+
+        @JvmStatic
+        fun getConnectivityStatus(context: Context): Int {
+            val cm =
+                context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+            val activeNetwork = cm.activeNetworkInfo
+            if (null != activeNetwork) {
+                if (activeNetwork.type == ConnectivityManager.TYPE_WIFI) return TYPE_WIFI
+                if (activeNetwork.type == ConnectivityManager.TYPE_MOBILE) return TYPE_MOBILE
+            }
+            return TYPE_NOT_CONNECTED
+        }
+
+        @JvmStatic
+        fun getConnectivityStatusString(context: Context): Int {
+            val conn: Int = getConnectivityStatus(context)
+            var status = 0
+            if (conn == TYPE_WIFI) {
+                status = NETWORK_STATUS_WIFI
+            } else if (conn == TYPE_MOBILE) {
+                status = NETWORK_STATUS_MOBILE
+            } else if (conn == TYPE_NOT_CONNECTED) {
+                status = NETWORK_STATUS_NOT_CONNECTED
+            }
+            return status
+        }
+    }
+}