Implement the favorite character screen.

Remove the search icon from the favorite screen.

app/src/main/java/cz/fel/barysole/ackeetesttask/MyNavHost.kt

@@ -12,6 +12,7 @@ import cz.fel.barysole.ackeetesttask.ui.screen.Screen
 import cz.fel.barysole.ackeetesttask.ui.screen.ScreenAction
 import cz.fel.barysole.ackeetesttask.ui.screen.characterdetail.CharacterDetailScreen
 import cz.fel.barysole.ackeetesttask.ui.screen.characterlist.CharacterListScreen
+import cz.fel.barysole.ackeetesttask.ui.screen.favorite.FavoriteCharacterListScreen
 import kotlinx.coroutines.flow.Flow
 
 @Composable
@@ -39,7 +40,14 @@ fun MyNavHost(
                 }
             )
         }
-        composable(Screen.Favorite.route) { onTopBarTitleChange("") }
+        composable(Screen.Favorite.route) { onTopBarTitleChange("")
+            FavoriteCharacterListScreen(
+                    onItemSelected = { characterId ->
+                navController.navigate(Screen.CharacterDetail.routeWithoutArgument + "/" + characterId) {
+                    launchSingleTop = true
+                }
+            })
+        }
         composable(
             Screen.CharacterDetail.route,
             arguments = listOf(navArgument("characterId") { type = NavType.LongType })

app/src/main/java/cz/fel/barysole/ackeetesttask/db/room/dao/CharacterDao.kt

@@ -16,9 +16,12 @@ interface CharacterDao {
     @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insertAll(repos: List<CharacterInfo>)
 
-    @Query("SELECT * FROM CharacterInfo")
+    @Query("SELECT * FROM CharacterInfo ORDER BY id ASC")
     fun getAll(): PagingSource<Int, CharacterInfo>
 
+    @Query("SELECT * FROM CharacterInfo WHERE isFavorite = 1 ORDER BY id ASC")
+    fun getFavorite(): PagingSource<Int, CharacterInfo>
+
     @Query("SELECT * FROM CharacterInfo WHERE id=:id")
     suspend fun getById(id: Long): CharacterInfo?
 
@@ -28,7 +31,4 @@ interface CharacterDao {
                 "ORDER BY id ASC"
     )
     fun getCharactersByName(characterName: String): PagingSource<Int, CharacterInfo>
-
-    @Query("DELETE FROM CharacterInfo WHERE isFavorite = 'false'")
-    suspend fun deleteNotFavorite()
 }
\ No newline at end of file

app/src/main/java/cz/fel/barysole/ackeetesttask/repository/characters/CharacterRepository.kt

@@ -10,6 +10,8 @@ interface CharacterRepository {
 
     fun getCharactersFlow(): Flow<PagingData<CharacterInfo>>
 
+    fun getFavoriteCharactersFlow(): Flow<PagingData<CharacterInfo>>
+
     suspend fun getCharacter(characterId: Long): CharacterInfo?
 
     suspend fun changeCharacterFavoriteStatus(characterId: Long)

app/src/main/java/cz/fel/barysole/ackeetesttask/repository/characters/CharacterRepositoryImpl.kt

@@ -4,17 +4,12 @@ import androidx.paging.ExperimentalPagingApi
 import androidx.paging.Pager
 import androidx.paging.PagingConfig
 import androidx.paging.PagingData
-import androidx.paging.RemoteMediator
 import androidx.room.withTransaction
 import cz.fel.barysole.ackeetesttask.api.RickAndMortyApi
 import cz.fel.barysole.ackeetesttask.db.room.AppDatabase
 import cz.fel.barysole.ackeetesttask.db.room.dao.CharacterDao
 import cz.fel.barysole.ackeetesttask.model.CharacterInfo
-import cz.fel.barysole.ackeetesttask.model.PaginationInfo
-import cz.fel.barysole.ackeetesttask.repository.pagination.PaginationDataType
 import kotlinx.coroutines.flow.Flow
-import retrofit2.HttpException
-import java.io.IOException
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -31,7 +26,7 @@ class CharacterRepositoryImpl @Inject constructor(
                 pageSize = NETWORK_PAGE_SIZE,
                 enablePlaceholders = false
             ),
-            pagingSourceFactory = { CharactersPagingSource(rickAndMortyApi, characterNameQuery) }
+            pagingSourceFactory = { CharactersSearchPagingSource(rickAndMortyApi, characterNameQuery) }
         ).flow
     }
 
@@ -47,6 +42,16 @@ class CharacterRepositoryImpl @Inject constructor(
         ).flow
     }
 
+    override fun getFavoriteCharactersFlow(): Flow<PagingData<CharacterInfo>> {
+        return Pager(
+            config = PagingConfig(
+                pageSize = NETWORK_PAGE_SIZE,
+                enablePlaceholders = false
+            ),
+            pagingSourceFactory = { appDatabase.characterDao().getFavorite() }
+        ).flow
+    }
+
     override suspend fun getCharacter(characterId: Long): CharacterInfo? {
             val response = rickAndMortyApi.getCharacterById(characterId)
             appDatabase.withTransaction {
@@ -71,7 +76,6 @@ class CharacterRepositoryImpl @Inject constructor(
         // Save isFavorite flag during items update in the DB
         suspend fun insertCharacterItems(items: List<CharacterInfo>, characterDao: CharacterDao) {
             // clear the character table in the database
-            characterDao.deleteNotFavorite()
             for (item in items) {
                 val itemInDb = characterDao.getById(item.id)
                 if (itemInDb?.isFavorite == true) {

app/src/main/java/cz/fel/barysole/ackeetesttask/repository/characters/CharactersPagingSource.kt → app/src/main/java/cz/fel/barysole/ackeetesttask/repository/characters/CharactersSearchPagingSource.kt

@@ -7,7 +7,7 @@ import cz.fel.barysole.ackeetesttask.model.CharacterInfo
 import retrofit2.HttpException
 import java.io.IOException
 
-class CharactersPagingSource(
+class CharactersSearchPagingSource(
     private val rickAndMortyApi: RickAndMortyApi,
     private val characterName: String
 ) : PagingSource<Int, CharacterInfo>() {

app/src/main/java/cz/fel/barysole/ackeetesttask/ui/screen/Screen.kt

@@ -22,8 +22,7 @@ sealed class Screen(
     object Favorite : Screen(
         "favorite",
         R.string.favorite,
-        R.drawable.baseline_star_24,
-        actionList = listOf(ScreenAction.SearchCharacterScreenAction)
+        R.drawable.baseline_star_24
     )
 
     object CharacterDetail : Screen(

app/src/main/java/cz/fel/barysole/ackeetesttask/ui/screen/favorite/FavoriteCharacterListScreen.kt

+package cz.fel.barysole.ackeetesttask.ui.screen.favorite
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.material3.Button
+import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.paging.compose.collectAsLazyPagingItems
+import cz.fel.barysole.ackeetesttask.ui.uielement.character.CharacterList
+
+@Composable
+fun FavoriteCharacterListScreen(
+    onItemSelected: (id: Long) -> Unit,
+    favoriteCharacterListViewModel: FavoriteCharacterListViewModel = hiltViewModel()
+) {
+    favoriteCharacterListViewModel.refreshList()
+    val favoriteCharacters =
+        favoriteCharacterListViewModel.pagingDataFlow.collectAsLazyPagingItems()
+    Surface(
+        color = MaterialTheme.colorScheme.background
+    ) {
+        if (favoriteCharacters.itemCount == 0) {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .fillMaxHeight(),
+                verticalArrangement = Arrangement.Center,
+                horizontalAlignment = Alignment.CenterHorizontally
+            ) {
+                    Text("There is no favorite characters yet.")
+            }
+        } else {
+            CharacterList(favoriteCharacters, onItemSelected)
+        }
+    }
+}
\ No newline at end of file

app/src/main/java/cz/fel/barysole/ackeetesttask/ui/screen/favorite/FavoriteCharacterListViewModel.kt

+package cz.fel.barysole.ackeetesttask.ui.screen.favorite
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import androidx.paging.PagingData
+import androidx.paging.cachedIn
+import androidx.room.withTransaction
+import cz.fel.barysole.ackeetesttask.db.room.AppDatabase
+import cz.fel.barysole.ackeetesttask.model.CharacterInfo
+import cz.fel.barysole.ackeetesttask.repository.characters.CharacterRepository
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.onStart
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@HiltViewModel
+class FavoriteCharacterListViewModel @Inject constructor(
+    private val characterRepository: CharacterRepository,
+    private val appDatabase: AppDatabase
+) : ViewModel() {
+
+    // The UI state
+    private val _uiState = MutableStateFlow(UiState())
+    val uiState: StateFlow<UiState> = _uiState.asStateFlow()
+    val pagingDataFlow: Flow<PagingData<CharacterInfo>>
+
+    private val getFavoriteCharacters = MutableSharedFlow<Unit>()
+
+    init {
+        pagingDataFlow = getFavoriteCharacters
+            .onStart { emit(Unit) }
+            .flatMapLatest { characterRepository.getFavoriteCharactersFlow() }
+            .cachedIn(viewModelScope)
+    }
+
+    fun refreshList() {
+        viewModelScope.launch { getFavoriteCharacters.emit(Unit) }
+    }
+
+    fun showLoadingError(hasError: Boolean) {
+        _uiState.value = UiState(showError = hasError)
+    }
+
+    data class UiState(
+        val showError: Boolean = false
+    )
+
+}
\ No newline at end of file