actors-paging impl.

app/src/main/java/com/commandiron/toprated10films/data/mapper/ActorMapper.kt

@@ -1,10 +1,11 @@
 package com.commandiron.toprated10films.data.mapper
 
 import com.commandiron.toprated10films.data.model.movie_db_actor.MovieDbActor
-import com.commandiron.toprated10films.ui.model.Actor
+import com.commandiron.toprated10films.domain.model.Actor
 
 fun MovieDbActor.toActor(): Actor {
     return Actor(
+        id = id,
         name = name,
         imageUrl = "https://image.tmdb.org/t/p/original/$profile_path"
     )

app/src/main/java/com/commandiron/toprated10films/data/paging/ActorPagingSource.kt

@@ -0,0 +1,40 @@
+package com.commandiron.toprated10films.data.paging
+
+import androidx.paging.PagingSource
+import androidx.paging.PagingState
+import com.commandiron.toprated10films.data.mapper.toActor
+import com.commandiron.toprated10films.data.remote.MovieApi
+import com.commandiron.toprated10films.domain.model.Actor
+
+class ActorPagingSource(
+    private val api: MovieApi
+) : PagingSource<Int, Actor>() {
+
+    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, Actor> {
+        val currentPage = params.key ?: 1
+        return try {
+            val response = api.getActors(currentPage)
+            val endOfPaginationReached = response.page == response.total_pages
+            if (!endOfPaginationReached) {
+                LoadResult.Page(
+                    data = response.movieDbActors.map { it.toActor() },
+                    prevKey = if (currentPage == 1) null else currentPage - 1,
+                    nextKey = currentPage + 1
+                )
+            } else {
+                LoadResult.Page(
+                    data = emptyList(),
+                    prevKey = null,
+                    nextKey = null
+                )
+            }
+        } catch (e: Exception) {
+            LoadResult.Error(e)
+        }
+    }
+
+    override fun getRefreshKey(state: PagingState<Int, Actor>): Int? {
+        return state.anchorPosition
+    }
+
+}

app/src/main/java/com/commandiron/toprated10films/data/repository/AppRepositoryImpl.kt

@@ -1,12 +1,15 @@
 package com.commandiron.toprated10films.data.repository
 
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
 import com.commandiron.toprated10films.data.local.AppDao
-import com.commandiron.toprated10films.data.mapper.toActor
 import com.commandiron.toprated10films.data.mapper.toGenre
+import com.commandiron.toprated10films.data.paging.ActorPagingSource
 import com.commandiron.toprated10films.data.remote.MovieApi
 import com.commandiron.toprated10films.domain.model.Genre
 import com.commandiron.toprated10films.domain.repository.AppRepository
-import com.commandiron.toprated10films.ui.model.Actor
+import com.commandiron.toprated10films.domain.model.Actor
 import com.commandiron.toprated10films.util.Response
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
@@ -37,14 +40,10 @@ class AppRepositoryImpl(
         dao.insertGenre(*genres.toTypedArray())
     }
 
-    override suspend fun getActors(page: Int): Flow<Response<List<Actor>>> = flow {
-        emit(Response.Loading)
-        try {
-            val actors: List<Actor> = api.getActors(page).movieDbActors.map { it.toActor() }
-            emit(Response.Success(actors))
-        }catch (e: Exception) {
-            emit(Response.Error(e.message ?: "AN_ERROR_OCCURRED"))
-            e.printStackTrace()
-        }
+    override suspend fun getActors(): Flow<PagingData<Actor>> {
+        return Pager(
+            config = PagingConfig(pageSize = 20),
+            pagingSourceFactory = { ActorPagingSource(api) }
+        ).flow
     }
 }

app/src/main/java/com/commandiron/toprated10films/domain/model/Actor.kt

@@ -0,0 +1,7 @@
+package com.commandiron.toprated10films.domain.model
+
+data class Actor(
+    val id: Int,
+    val name: String,
+    val imageUrl: String
+)

app/src/main/java/com/commandiron/toprated10films/domain/repository/AppRepository.kt

@@ -1,12 +1,13 @@
 package com.commandiron.toprated10films.domain.repository
 
+import androidx.paging.PagingData
 import com.commandiron.toprated10films.domain.model.Genre
-import com.commandiron.toprated10films.ui.model.Actor
+import com.commandiron.toprated10films.domain.model.Actor
 import com.commandiron.toprated10films.util.Response
 import kotlinx.coroutines.flow.Flow
 
 interface AppRepository {
     suspend fun getGenres(): Flow<Response<List<Genre>>>
     suspend fun saveGenres(genres: List<Genre>)
-    suspend fun getActors(page: Int): Flow<Response<List<Actor>>>
+    suspend fun getActors(): Flow<PagingData<Actor>>
 }

app/src/main/java/com/commandiron/toprated10films/domain/use_cases/GetActors.kt

@@ -1,12 +1,12 @@
 package com.commandiron.toprated10films.domain.use_cases
 
+import androidx.paging.PagingData
 import com.commandiron.toprated10films.domain.repository.AppRepository
-import com.commandiron.toprated10films.ui.model.Actor
-import com.commandiron.toprated10films.util.Response
+import com.commandiron.toprated10films.domain.model.Actor
 import kotlinx.coroutines.flow.Flow
 
 class GetActors(
     private val repository: AppRepository
 ) {
-    suspend operator fun invoke(page: Int): Flow<Response<List<Actor>>> = repository.getActors(page)
+    suspend operator fun invoke(): Flow<PagingData<Actor>> = repository.getActors()
 }

app/src/main/java/com/commandiron/toprated10films/ui/presentation/actor/ActorScreen.kt

@@ -5,7 +5,6 @@ import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
-import androidx.compose.foundation.lazy.grid.items
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
@@ -20,7 +19,9 @@ import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
 import androidx.compose.ui.text.style.TextAlign
 import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.paging.compose.collectAsLazyPagingItems
 import com.commandiron.toprated10films.ui.presentation.actor.components.ActorCard
+import com.commandiron.toprated10films.ui.presentation.actor.components.items
 import com.commandiron.toprated10films.ui.presentation.components.SearchTextField
 import com.commandiron.toprated10films.ui.theme.spacing
 
@@ -31,7 +32,7 @@ fun ActorScreen(
     onClick: (actorName: String) -> Unit
 ) {
     val searchText = viewModel.searchText.collectAsState().value
-    val actors = viewModel.actors.collectAsState().value
+    val actors = viewModel.actors.collectAsLazyPagingItems()
     val isLoading = viewModel.isLoading.collectAsState().value
     val keyboardController = LocalSoftwareKeyboardController.current
     val focusManager = LocalFocusManager.current
@@ -94,28 +95,32 @@ fun ActorScreen(
                         horizontal = MaterialTheme.spacing.spaceMedium
                     )
                 ){
-                    items(actors) { actor ->
-                        ActorCard(
-                            modifier = Modifier
-                                .padding(MaterialTheme.spacing.spaceExtraSmall)
-                                .clip(MaterialTheme.shapes.medium)
-                                .aspectRatio(0.75f)
-                                .clickable(
-                                    interactionSource = remember { MutableInteractionSource() },
-                                    indication = null
-                                ) {
-                                    if (isImeVisible) {
-                                        focusManager.clearFocus()
-                                        keyboardController?.hide()
-                                    } else {
-                                        onClick(actor.name)
-                                    }
-                                },
-                            actor = actor
-                        )
-                    }
-                    item {
-                        Spacer(Modifier.height(MaterialTheme.spacing.spaceXXXLarge))
+                    items(
+                        items = actors,
+                        key = { actor ->
+                            actor.id
+                        }
+                    ) { actor ->
+                        actor?.let {
+                            ActorCard(
+                                modifier = Modifier
+                                    .padding(MaterialTheme.spacing.spaceExtraSmall)
+                                    .clip(MaterialTheme.shapes.medium)
+                                    .aspectRatio(0.75f)
+                                    .clickable(
+                                        interactionSource = remember { MutableInteractionSource() },
+                                        indication = null
+                                    ) {
+                                        if (isImeVisible) {
+                                            focusManager.clearFocus()
+                                            keyboardController?.hide()
+                                        } else {
+                                            onClick(it.name)
+                                        }
+                                    },
+                                actor = it
+                            )
+                        }
                     }
                 }
             }

app/src/main/java/com/commandiron/toprated10films/ui/presentation/actor/ActorViewModel.kt

@@ -2,9 +2,10 @@ package com.commandiron.toprated10films.ui.presentation.actor
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import androidx.paging.PagingData
+import androidx.paging.cachedIn
 import com.commandiron.toprated10films.domain.use_cases.UseCases
-import com.commandiron.toprated10films.ui.model.Actor.Companion.defaultActorList
-import com.commandiron.toprated10films.util.Response
+import com.commandiron.toprated10films.domain.model.Actor
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -16,8 +17,8 @@ class ActorViewModel @Inject constructor(
     private val useCases: UseCases
 ): ViewModel() {
 
-    private val _actors = MutableStateFlow(defaultActorList)
-    val actors = _actors.asStateFlow()
+    private val _actors = MutableStateFlow<PagingData<Actor>>(PagingData.empty())
+    val actors = _actors
 
     private val _searchText = MutableStateFlow("")
     val searchText = _searchText.asStateFlow()
@@ -27,19 +28,8 @@ class ActorViewModel @Inject constructor(
 
     init {
         viewModelScope.launch {
-            useCases.getActors(2).collect { response ->
-                when(response) {
-                    is Response.Error -> {
-
-                    }
-                    Response.Loading -> {
-
-                    }
-                    is Response.Success -> {
-                        println(response.data)
-                        _actors.value = response.data
-                    }
-                }
+            useCases.getActors().cachedIn(viewModelScope).collect { response ->
+                actors.value = response
             }
         }
     }

app/src/main/java/com/commandiron/toprated10films/ui/presentation/actor/components/ActorCard.kt

@@ -13,7 +13,7 @@ import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.style.TextOverflow
-import com.commandiron.toprated10films.ui.model.Actor
+import com.commandiron.toprated10films.domain.model.Actor
 import com.commandiron.toprated10films.ui.presentation.components.CustomAsyncImage
 import com.commandiron.toprated10films.ui.presentation.components.TopTenSticker
 import com.commandiron.toprated10films.ui.theme.spacing

app/src/main/java/com/commandiron/toprated10films/ui/presentation/actor/components/LazyGridScopeExt.kt

@@ -0,0 +1,52 @@
+package com.commandiron.toprated10films.ui.presentation.actor.components
+
+import android.annotation.SuppressLint
+import android.os.Parcel
+import android.os.Parcelable
+import androidx.compose.foundation.lazy.grid.LazyGridItemScope
+import androidx.compose.foundation.lazy.grid.LazyGridScope
+import androidx.compose.runtime.Composable
+import androidx.paging.compose.LazyPagingItems
+
+fun <T : Any> LazyGridScope.items(
+    items: LazyPagingItems<T>,
+    key: ((item: T) -> Any)? = null,
+    itemContent: @Composable LazyGridItemScope.(item: T?) -> Unit
+) {
+    items(
+        count = items.itemCount,
+        key = if (key == null) null else { index ->
+            val item = items.peek(index)
+            if (item == null) {
+                PagingPlaceholderKey(index)
+            } else {
+                key(item)
+            }
+        }
+    ) { index ->
+        itemContent(items[index])
+    }
+}
+
+@SuppressLint("BanParcelableUsage")
+private data class PagingPlaceholderKey(private val index: Int) : Parcelable {
+    override fun writeToParcel(parcel: Parcel, flags: Int) {
+        parcel.writeInt(index)
+    }
+
+    override fun describeContents(): Int {
+        return 0
+    }
+
+    companion object {
+        @Suppress("unused")
+        @JvmField
+        val CREATOR: Parcelable.Creator<PagingPlaceholderKey> =
+            object : Parcelable.Creator<PagingPlaceholderKey> {
+                override fun createFromParcel(parcel: Parcel) =
+                    PagingPlaceholderKey(parcel.readInt())
+
+                override fun newArray(size: Int) = arrayOfNulls<PagingPlaceholderKey?>(size)
+            }
+    }
+}

app/src/main/java/com/commandiron/toprated10films/ui/presentation/selection/SelectionViewModel.kt

@@ -15,4 +15,5 @@ class SelectionViewModel @Inject constructor(
 
     private val _populars = MutableStateFlow(defaultPopularList)
     val populars = _populars.asStateFlow()
+
 }

app/src/main/java/com/commandiron/toprated10films/ui/presentation/selection/components/PopularCard.kt

@@ -6,6 +6,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.ui.Modifier
+import com.commandiron.toprated10films.domain.model.Actor
 import com.commandiron.toprated10films.domain.model.Genre
 import com.commandiron.toprated10films.ui.model.*
 import com.commandiron.toprated10films.ui.presentation.actor.components.ActorCard
@@ -24,6 +25,7 @@ fun PopularCard(
                 Category.ByActor -> {
                     ActorCard(
                         actor = Actor(
+                            id = 0,
                             name = popular.title,
                             imageUrl = popular.imageUrl ?: ""
                         ),