refactor: put navigation logic into main view

app/src/main/java/com/example/tvcontroller/MainActivity.kt

@@ -5,24 +5,8 @@ import android.util.Log
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.Icon
-import androidx.compose.material3.NavigationBar
-import androidx.compose.material3.NavigationBarItem
-import androidx.compose.material3.Scaffold
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.res.painterResource
 import androidx.core.app.ActivityCompat
 import androidx.lifecycle.lifecycleScope
-import androidx.navigation.NavHostController
-import androidx.navigation.compose.NavHost
-import androidx.navigation.compose.composable
-import androidx.navigation.compose.currentBackStackEntryAsState
-import androidx.navigation.compose.rememberNavController
 import com.example.tvcontroller.client.WebClient
 import com.example.tvcontroller.client.WebsocketClient
 import com.example.tvcontroller.services.BluetoothService
@@ -31,9 +15,7 @@ import com.example.tvcontroller.services.ControllerService
 import com.example.tvcontroller.services.DeviceService
 import com.example.tvcontroller.services.webrtc.WebRtcService
 import com.example.tvcontroller.ui.theme.TVControllerTheme
-import com.example.tvcontroller.ui.views.CameraView
-import com.example.tvcontroller.ui.views.RemoteView
-import com.example.tvcontroller.ui.views.SettingsView
+import com.example.tvcontroller.ui.views.MainView
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 
@@ -77,7 +59,7 @@ class MainActivity : ComponentActivity() {
         enableEdgeToEdge()
         setContent {
             TVControllerTheme {
-                TvControllerApp(
+                MainView(
                     deviceService = deviceService,
                     controllerService = controllerService,
                     bluetoothService = bluetoothService,
@@ -101,67 +83,3 @@ class MainActivity : ComponentActivity() {
     }
 }
 
-@Composable
-fun TvControllerApp(
-    navController: NavHostController = rememberNavController(),
-    deviceService: DeviceService,
-    controllerService: ControllerService,
-    bluetoothService: BluetoothService,
-    webRtcService: WebRtcService,
-    cameraService: CameraService
-) {
-    val backStackEntry by navController.currentBackStackEntryAsState()
-    val currentScreen = Screen.valueOf(backStackEntry?.destination?.route ?: Screen.Camera.name)
-    val baselineCamera24 = painterResource(R.drawable.baseline_camera_24)
-    val baselineRemote24 = painterResource(R.drawable.baseline_settings_remote_24)
-    val baselineSettings24 = painterResource(R.drawable.baseline_settings_24)
-    Scaffold(modifier = Modifier.fillMaxSize(), bottomBar = {
-        NavigationBar {
-            NavigationBarItem(
-                onClick = { navController.navigate(Screen.Camera.name) }, icon = {
-                    Icon(
-                        baselineCamera24, contentDescription = "Camera"
-                    )
-                }, label = { Text("Camera") }, selected = currentScreen == Screen.Camera
-            )
-            NavigationBarItem(
-                onClick = { navController.navigate(Screen.Remote.name) }, icon = {
-                    Icon(
-                        baselineRemote24, contentDescription = "Remote"
-                    )
-                }, label = { Text("Remote") }, selected = currentScreen == Screen.Remote
-            )
-            NavigationBarItem(
-                onClick = { navController.navigate(Screen.Settings.name) }, icon = {
-                    Icon(
-                        baselineSettings24, contentDescription = "Settings"
-                    )
-                }, label = { Text("Settings") }, selected = currentScreen == Screen.Settings
-            )
-        }
-    }) { innerPadding ->
-        NavHost(
-            navController = navController,
-            startDestination = Screen.Settings.name,
-            modifier = Modifier.padding(innerPadding)
-        ) {
-            composable(route = Screen.Camera.name) {
-                CameraView(
-                    eglBaseContext = cameraService.eglBaseContext,
-                    videoTrack = webRtcService.videoTrack
-                )
-            }
-            composable(route = Screen.Remote.name) {
-                RemoteView(
-                    controllerService = controllerService
-                )
-            }
-            composable(route = Screen.Settings.name) {
-                SettingsView(
-                    deviceService = deviceService, bluetoothService = bluetoothService
-                )
-            }
-        }
-    }
-}
-

app/src/main/java/com/example/tvcontroller/Screen.kt

@@ -1,7 +0,0 @@
-package com.example.tvcontroller
-
-enum class Screen {
-    Camera,
-    Remote,
-    Settings
-}

app/src/main/java/com/example/tvcontroller/ui/views/MainView.kt

@@ -0,0 +1,96 @@
+package com.example.tvcontroller.ui.views
+
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Icon
+import androidx.compose.material3.NavigationBar
+import androidx.compose.material3.NavigationBarItem
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.painterResource
+import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
+import androidx.navigation.compose.currentBackStackEntryAsState
+import androidx.navigation.compose.rememberNavController
+import com.example.tvcontroller.R
+import com.example.tvcontroller.services.BluetoothService
+import com.example.tvcontroller.services.CameraService
+import com.example.tvcontroller.services.ControllerService
+import com.example.tvcontroller.services.DeviceService
+import com.example.tvcontroller.services.webrtc.WebRtcService
+import com.example.tvcontroller.ui.views.MainViewModel.Companion.CAMERA_VIEW
+import com.example.tvcontroller.ui.views.MainViewModel.Companion.REMOTE_VIEW
+import com.example.tvcontroller.ui.views.MainViewModel.Companion.SETTINGS_VIEW
+
+@Composable
+fun MainView(
+    deviceService: DeviceService,
+    controllerService: ControllerService,
+    bluetoothService: BluetoothService,
+    webRtcService: WebRtcService,
+    cameraService: CameraService
+) {
+    val viewModel = viewModel<MainViewModel>()
+    val navController = rememberNavController()
+    val backStackEntry by navController.currentBackStackEntryAsState()
+    val currentView = backStackEntry?.destination?.route
+    val baselineCamera24 = painterResource(R.drawable.baseline_camera_24)
+    val baselineRemote24 = painterResource(R.drawable.baseline_settings_remote_24)
+    val baselineSettings24 = painterResource(R.drawable.baseline_settings_24)
+    Scaffold(modifier = Modifier.fillMaxSize(), bottomBar = {
+        NavigationBar {
+            NavigationBarItem(
+                onClick = { navController.navigate(CAMERA_VIEW) }, icon = {
+                    Icon(
+                        baselineCamera24, contentDescription = "Camera"
+                    )
+                }, label = { Text("Camera") }, selected = currentView == CAMERA_VIEW
+            )
+            NavigationBarItem(
+                onClick = { navController.navigate(REMOTE_VIEW) }, icon = {
+                    Icon(
+                        baselineRemote24, contentDescription = "Remote"
+                    )
+                }, label = { Text("Remote") }, selected = currentView == REMOTE_VIEW
+            )
+            NavigationBarItem(
+                onClick = { navController.navigate(SETTINGS_VIEW) },
+                icon = {
+                    Icon(
+                        baselineSettings24, contentDescription = "Settings"
+                    )
+                },
+                label = { Text("Settings") },
+                selected = currentView == SETTINGS_VIEW
+            )
+        }
+    }) { innerPadding ->
+        NavHost(
+            navController = navController,
+            startDestination = viewModel.currentView.value,
+            modifier = Modifier.padding(innerPadding)
+        ) {
+            composable(route = CAMERA_VIEW) {
+                CameraView(
+                    eglBaseContext = cameraService.eglBaseContext,
+                    videoTrack = webRtcService.videoTrack
+                )
+            }
+            composable(route = REMOTE_VIEW) {
+                RemoteView(
+                    controllerService = controllerService
+                )
+            }
+            composable(route = SETTINGS_VIEW) {
+                SettingsView(
+                    deviceService = deviceService, bluetoothService = bluetoothService
+                )
+            }
+        }
+    }
+}
+

app/src/main/java/com/example/tvcontroller/ui/views/MainViewModel.kt

@@ -0,0 +1,14 @@
+package com.example.tvcontroller.ui.views
+
+import androidx.compose.runtime.mutableStateOf
+import androidx.lifecycle.ViewModel
+
+class MainViewModel : ViewModel() {
+    var currentView = mutableStateOf(CAMERA_VIEW)
+
+    companion object {
+        const val CAMERA_VIEW = "camera_view"
+        const val REMOTE_VIEW = "remote_view"
+        const val SETTINGS_VIEW = "settings_view"
+    }
+}