Prepare sample

Change-Id: I3870ea748e91795947f296ecf814dd5bc143f32e

app/src/main/java/com/google/samples/apps/nowinandroid/ui/NiaApp.kt

@@ -16,56 +16,54 @@
 
 package com.google.samples.apps.nowinandroid.ui
 
-import androidx.compose.foundation.layout.ExperimentalLayoutApi
-import androidx.compose.foundation.layout.WindowInsets
-import androidx.compose.foundation.layout.consumeWindowInsets
-import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.safeDrawing
-import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
-import androidx.navigation.NavType
-import androidx.navigation.compose.NavHost
-import androidx.navigation.compose.composable
-import androidx.navigation.compose.rememberNavController
-import androidx.navigation.navArgument
 import com.google.samples.apps.nowinandroid.feature.interests.InterestsRoute
-import com.google.samples.apps.nowinandroid.feature.interests.navigation.interestsRoute
 import com.google.samples.apps.nowinandroid.feature.topic.TopicRoute
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.navigateToTopic
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.topicIdArg
 
-@OptIn(
-    ExperimentalLayoutApi::class,
-)
 @Composable
 fun NiaApp() {
     Scaffold { padding ->
-        val navController = rememberNavController()
-        NavHost(
-            navController = navController,
-            startDestination = interestsRoute,
-            modifier = Modifier
-                .fillMaxSize()
-                .padding(padding)
-                .consumeWindowInsets(padding)
-                .windowInsetsPadding(WindowInsets.safeDrawing),
-        ) {
-            composable(route = interestsRoute) {
-                InterestsRoute(onTopicClick = navController::navigateToTopic)
-            }
-            composable(
-                route = "topic_route/{$topicIdArg}",
-                arguments = listOf(
-                    navArgument(topicIdArg) { type = NavType.StringType },
-                ),
+        Box(modifier = Modifier.padding(padding)) {
+            var selectedTopicId: String? by remember { mutableStateOf(null) }
+            var isTopicListVisible: Boolean by remember { mutableStateOf(false) }
+
+            InterestsRoute(
+                onTopicClick = { topicId ->
+                    selectedTopicId = topicId
+                    isTopicListVisible = true
+                },
+            )
+
+            AnimatedVisibility(
+                visible = isTopicListVisible,
+                enter = slideInHorizontally(),
+                exit = slideOutHorizontally()
             ) {
-                TopicRoute(
-                    onBackClick = navController::popBackStack,
-                    onTopicClick = navController::navigateToTopic
-                )
+                selectedTopicId?.let { id ->
+                    Surface {
+                        TopicRoute(
+                            topicId = id,
+                            onBackClick = {
+                                isTopicListVisible = false
+                            },
+                            onTopicClick = { topicId ->
+                                selectedTopicId = topicId
+                            }
+                        )
+                    }
+                }
             }
         }
     }

feature/topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicScreen.kt

@@ -36,6 +36,7 @@ import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -61,11 +62,16 @@ import com.google.samples.apps.nowinandroid.feature.topic.R.string
 
 @Composable
 fun TopicRoute(
+    topicId: String,
     onBackClick: () -> Unit,
     onTopicClick: (String) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: TopicViewModel = hiltViewModel(),
 ) {
+    LaunchedEffect(key1 = topicId) {
+        viewModel.setTopicId(topicId)
+    }
+
     val topicUiState: TopicUiState by viewModel.topicUiState.collectAsStateWithLifecycle()
     val newsUiState: NewsUiState by viewModel.newUiState.collectAsStateWithLifecycle()
 
@@ -100,9 +106,6 @@ internal fun TopicScreen(
         modifier = modifier,
         horizontalAlignment = Alignment.CenterHorizontally,
     ) {
-        item {
-            Spacer(Modifier.windowInsetsTopHeight(WindowInsets.safeDrawing))
-        }
         when (topicUiState) {
             TopicUiState.Loading -> item {
                 NiaLoadingWheel(

feature/topic/src/main/java/com/google/samples/apps/nowinandroid/feature/topic/TopicViewModel.kt

@@ -16,25 +16,25 @@
 
 package com.google.samples.apps.nowinandroid.feature.topic
 
-import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.google.samples.apps.nowinandroid.core.data.repository.NewsResourceQuery
 import com.google.samples.apps.nowinandroid.core.data.repository.TopicsRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.UserDataRepository
 import com.google.samples.apps.nowinandroid.core.data.repository.UserNewsResourceRepository
-import com.google.samples.apps.nowinandroid.core.decoder.StringDecoder
 import com.google.samples.apps.nowinandroid.core.model.data.FollowableTopic
 import com.google.samples.apps.nowinandroid.core.model.data.Topic
 import com.google.samples.apps.nowinandroid.core.model.data.UserNewsResource
 import com.google.samples.apps.nowinandroid.core.result.Result
 import com.google.samples.apps.nowinandroid.core.result.asResult
-import com.google.samples.apps.nowinandroid.feature.topic.navigation.TopicArgs
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
@@ -42,30 +42,32 @@ import javax.inject.Inject
 
 @HiltViewModel
 class TopicViewModel @Inject constructor(
-    savedStateHandle: SavedStateHandle,
-    stringDecoder: StringDecoder,
     private val userDataRepository: UserDataRepository,
     topicsRepository: TopicsRepository,
     userNewsResourceRepository: UserNewsResourceRepository,
 ) : ViewModel() {
 
-    private val topicArgs: TopicArgs = TopicArgs(savedStateHandle, stringDecoder)
+    private val topicId: MutableStateFlow<String?> = MutableStateFlow(null)
 
-    val topicUiState: StateFlow<TopicUiState> = topicUiState(
-        topicId = topicArgs.topicId,
-        userDataRepository = userDataRepository,
-        topicsRepository = topicsRepository,
-    ).stateIn(
+    val topicUiState: StateFlow<TopicUiState> = topicId.filterNotNull().flatMapLatest { id ->
+        topicUiState(
+            topicId = id,
+            userDataRepository = userDataRepository,
+            topicsRepository = topicsRepository,
+        )
+    }.stateIn(
         scope = viewModelScope,
         started = SharingStarted.WhileSubscribed(5_000),
         initialValue = TopicUiState.Loading,
     )
 
-    val newUiState: StateFlow<NewsUiState> = newsUiState(
-        topicId = topicArgs.topicId,
-        userDataRepository = userDataRepository,
-        userNewsResourceRepository = userNewsResourceRepository,
-    ).stateIn(
+    val newUiState: StateFlow<NewsUiState> = topicId.filterNotNull().flatMapLatest { id ->
+        newsUiState(
+            topicId = id,
+            userNewsResourceRepository = userNewsResourceRepository,
+            userDataRepository = userDataRepository,
+        )
+    }.stateIn(
         scope = viewModelScope,
         started = SharingStarted.WhileSubscribed(5_000),
         initialValue = NewsUiState.Loading,
@@ -73,7 +75,9 @@ class TopicViewModel @Inject constructor(
 
     fun followTopicToggle(followed: Boolean) {
         viewModelScope.launch {
-            userDataRepository.toggleFollowedTopicId(topicArgs.topicId, followed)
+            topicId.value?.let { id ->
+                userDataRepository.toggleFollowedTopicId(id, followed)
+            }
         }
     }
 
@@ -88,6 +92,10 @@ class TopicViewModel @Inject constructor(
             userDataRepository.setNewsResourceViewed(newsResourceId, viewed)
         }
     }
+
+    fun setTopicId(id: String) {
+        topicId.value = id
+    }
 }
 
 private fun topicUiState(