add network check

app/src/main/java/hu/bme/kszk/szobatarsch/MainActivity.kt

@@ -6,13 +6,15 @@ import android.util.Log
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.compose.foundation.isSystemInDarkTheme
-import androidx.compose.foundation.layout.PaddingValues
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.*
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CloudOff
 import androidx.compose.material3.*
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.navigation.NavHostController
@@ -26,11 +28,13 @@ import com.google.firebase.FirebaseApp
 import com.google.firebase.auth.FirebaseAuth
 import com.google.firebase.auth.FirebaseUser
 import hu.bme.kszk.szobatarsch.composable.*
+import hu.bme.kszk.szobatarsch.data.ConnectionState
 import hu.bme.kszk.szobatarsch.data.UserThemeSetting
 import hu.bme.kszk.szobatarsch.firebase.User
 import hu.bme.kszk.szobatarsch.firebase.registerOrOverwriteUser
 import hu.bme.kszk.szobatarsch.ui.theme.SzobatarSCHTheme
 import hu.bme.kszk.szobatarsch.data.Theme
+import hu.bme.kszk.szobatarsch.data.connectivityState
 
 val firebaseUser: FirebaseUser? get() = FirebaseAuth.getInstance().currentUser
 
@@ -124,12 +128,27 @@ fun MainScreen() {
         context.startActivity(intent)*/
     }
 
+    val connection by connectivityState()
+
+    val isConnected = connection === ConnectionState.Available
+
     val navController = rememberNavController()
 
     Scaffold(
         modifier = Modifier.fillMaxSize(),
         bottomBar = { BottomNavigationBar(navController = navController) }
     ) {
+        /*if (isConnected) {
+            NavigationHost(navController = navController, paddingValues = it)
+        } else {
+            Column(
+                modifier = Modifier.fillMaxSize(),
+                verticalArrangement = Arrangement.Center,
+                horizontalAlignment = Alignment.CenterHorizontally
+            ) {
+                Icon(Icons.Default.CloudOff, contentDescription = null)
+            }
+        }*/
         NavigationHost(navController = navController, paddingValues = it)
     }
 }