Remove Interests2PaneViewModel as it was overkill for holding a single string value

Change-Id: I4767578028b55c2bc7b1763bdeef87345b9fbf06

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/interests2pane/Interests2PaneViewModel.kt

@@ -1,35 +0,0 @@
-/*
- * Copyright 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.samples.apps.nowinandroid.ui.interests2pane
-
-import androidx.lifecycle.SavedStateHandle
-import androidx.lifecycle.ViewModel
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.TOPIC_ID_ARG
-import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.flow.StateFlow
-import javax.inject.Inject
-
-@HiltViewModel
-class Interests2PaneViewModel @Inject constructor(
-    private val savedStateHandle: SavedStateHandle,
-) : ViewModel() {
-    val selectedTopicId: StateFlow<String?> = savedStateHandle.getStateFlow(TOPIC_ID_ARG, null)
-
-    fun onTopicClick(topicId: String?) {
-        savedStateHandle[TOPIC_ID_ARG] = topicId
-    }
-}

app/src/main/kotlin/com/google/samples/apps/nowinandroid/ui/interests2pane/InterestsListDetailScreen.kt

@@ -26,8 +26,9 @@ import androidx.compose.material3.adaptive.navigation.rememberListDetailPaneScaf
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
-import androidx.hilt.navigation.compose.hiltViewModel
-import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
@@ -39,7 +40,6 @@ import com.google.samples.apps.nowinandroid.feature.topic.navigation.navigateToT
 import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicScreen
 import kotlinx.serialization.Serializable
 
-
 @Serializable object TopicPlaceholderDestination
 @Serializable object DetailPaneNavHostDestination
 
@@ -50,13 +50,11 @@ fun NavGraphBuilder.interestsListDetailScreen() {
 }
 
 @Composable
-internal fun InterestsListDetailScreen(
-    viewModel: Interests2PaneViewModel = hiltViewModel(),
-) {
-    val selectedTopicId by viewModel.selectedTopicId.collectAsStateWithLifecycle()
+internal fun InterestsListDetailScreen() {
+    var selectedTopicId : String? by rememberSaveable { mutableStateOf(null) }
     InterestsListDetailScreen(
         selectedTopicId = selectedTopicId,
-        onTopicClick = viewModel::onTopicClick,
+        onTopicClick = { topicId -> selectedTopicId = topicId },
     )
 }