Removed Navigator from codebase

ground/src/main/java/com/google/android/ground/MainActivity.kt

@@ -27,17 +27,13 @@
 import androidx.compose.ui.platform.ComposeView
 import androidx.core.view.WindowInsetsCompat
 import androidx.lifecycle.lifecycleScope
+import androidx.navigation.NavDirections
 import androidx.navigation.fragment.NavHostFragment
 import com.google.android.ground.databinding.MainActBinding
 import com.google.android.ground.repository.UserRepository
 import com.google.android.ground.system.ActivityCallback
 import com.google.android.ground.system.ActivityStreams
 import com.google.android.ground.ui.common.BackPressListener
-import com.google.android.ground.ui.common.FinishApp
-import com.google.android.ground.ui.common.NavigateTo
-import com.google.android.ground.ui.common.NavigateUp
-import com.google.android.ground.ui.common.NavigationRequest
-import com.google.android.ground.ui.common.Navigator
 import com.google.android.ground.ui.common.ViewModelFactory
 import com.google.android.ground.ui.common.modalSpinner
 import com.google.android.ground.ui.home.HomeScreenFragmentDirections
@@ -57,7 +53,6 @@
 class MainActivity : AbstractActivity() {
   @Inject lateinit var activityStreams: ActivityStreams
   @Inject lateinit var viewModelFactory: ViewModelFactory
-  @Inject lateinit var navigator: Navigator
   @Inject lateinit var userRepository: UserRepository
 
   private lateinit var viewModel: MainViewModel
@@ -79,8 +74,6 @@
       }
     }
 
-    lifecycleScope.launch { navigator.getNavigateRequests().collect { onNavigate(it) } }
-
     val binding = MainActBinding.inflate(layoutInflater)
     setContentView(binding.root)
 
@@ -100,16 +93,16 @@
         showPermissionDeniedDialog(viewGroup)
       }
       MainUiState.OnUserSignedOut -> {
-        navigator.navigate(SignInFragmentDirections.showSignInScreen())
+        navigateTo(SignInFragmentDirections.showSignInScreen())
       }
       MainUiState.TosNotAccepted -> {
-        navigator.navigate(SignInFragmentDirections.showTermsOfService(false))
+        navigateTo(SignInFragmentDirections.showTermsOfService(false))
       }
       MainUiState.NoActiveSurvey -> {
-        navigator.navigate(SurveySelectorFragmentDirections.showSurveySelectorScreen(true))
+        navigateTo(SurveySelectorFragmentDirections.showSurveySelectorScreen(true))
       }
       MainUiState.ShowHomeScreen -> {
-        navigator.navigate(HomeScreenFragmentDirections.showHomeScreen())
+        navigateTo(HomeScreenFragmentDirections.showHomeScreen())
       }
       MainUiState.OnUserSigningIn -> {
         onSignInProgress(true)
@@ -137,7 +130,7 @@
                 },
                 onCloseApp = {
                   showDialog = false
-                  navigator.finishApp()
+                  finish()
                 },
               )
             }
@@ -152,14 +145,6 @@
     viewModel.windowInsets.postValue(insets)
   }
 
-  private fun onNavigate(navRequest: NavigationRequest) {
-    when (navRequest) {
-      is NavigateTo -> navHostFragment.navController.navigate(navRequest.directions)
-      is NavigateUp -> navigateUp()
-      is FinishApp -> finish()
-    }
-  }
-
   /**
    * The Android permissions API requires this callback to live in an Activity; here we dispatch the
    * result back to the PermissionManager for handling.
@@ -225,4 +210,8 @@
       signInProgressDialog = null
     }
   }
+
+  private fun navigateTo(directions: NavDirections) {
+    navHostFragment.navController.navigate(directions)
+  }
 }

ground/src/main/java/com/google/android/ground/ui/offlineareas/OfflineAreasFragment.kt

@@ -29,10 +29,12 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.testTag
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
+import com.google.android.ground.R
 import com.google.android.ground.databinding.OfflineAreasFragBinding
 import com.google.android.ground.ui.common.AbstractFragment
 import com.google.android.ground.ui.theme.AppTheme
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 
 /**
@@ -69,8 +71,11 @@ class OfflineAreasFragment : AbstractFragment() {
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     super.onViewCreated(view, savedInstanceState)
     lifecycleScope.launch {
-      viewModel.navigateToOfflineAreaSelector.collect {
-        findNavController().navigate(OfflineAreasFragmentDirections.showOfflineAreaSelector())
+      viewModel.navigateToOfflineAreaSelector.collectLatest {
+        val navController = findNavController()
+        if (navController.currentDestination?.id == R.id.offline_areas_fragment) {
+          navController.navigate(OfflineAreasFragmentDirections.showOfflineAreaSelector())
+        }
       }
     }
   }

ground/src/main/java/com/google/android/ground/ui/offlineareas/OfflineAreasViewModel.kt

@@ -49,7 +49,7 @@ internal constructor(private val offlineAreaRepository: OfflineAreaRepository) :
   val showNoAreasMessage: LiveData<Boolean>
   val showProgressSpinner: LiveData<Boolean>
 
-  private val _navigateToOfflineAreaSelector = MutableSharedFlow<Unit>(replay = 0)
+  private val _navigateToOfflineAreaSelector = MutableSharedFlow<Unit>(replay = 1)
   val navigateToOfflineAreaSelector = _navigateToOfflineAreaSelector.asSharedFlow()
 
   init {