Revert "refactor(android): move post save state logic to a Paging transform"

This reverts commit 3829abeb8f.

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 -   Do not schedule post update job every time the app starts
 -   Improve favicon loading to reduce unnecessary redraws
+-   Fix post lists being reloaded unnecessarily
 
 ## [1.11.0] - 2022-12-07
 

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/LobstersApp.kt

@@ -179,6 +179,7 @@ fun LobstersApp(
           NetworkPosts(
             lazyPagingItems = hottestPosts,
             listState = hottestListState,
+            isPostSaved = viewModel::isPostSaved,
             postActions = postActions,
           )
         }
@@ -189,6 +190,7 @@ fun LobstersApp(
           NetworkPosts(
             lazyPagingItems = newestPosts,
             listState = newestListState,
+            isPostSaved = viewModel::isPostSaved,
             postActions = postActions,
           )
         }

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/DatabasePosts.kt

@@ -13,7 +13,6 @@ import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.Divider
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
-import dev.msfjarvis.claw.common.posts.LobstersCard
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.ui.decorations.MonthHeader
 import dev.msfjarvis.claw.database.local.SavedPost
@@ -34,9 +33,9 @@ fun DatabasePosts(
     items.forEach { (month, posts) ->
       stickyHeader { MonthHeader(month = month) }
       items(posts) { item ->
-        LobstersCard(
-          post = item,
-          isSaved = true,
+        ListItem(
+          item = item,
+          isSaved = { true },
           postActions = postActions,
         )
 

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/ListItem.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright © 2021-2022 Harsh Shandilya.
+ * Use of this source code is governed by an MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT.
+ */
+package dev.msfjarvis.claw.android.ui.lists
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import androidx.compose.ui.Modifier
+import dev.msfjarvis.claw.common.posts.LobstersCard
+import dev.msfjarvis.claw.common.posts.PostActions
+import dev.msfjarvis.claw.database.local.SavedPost
+
+@Composable
+fun ListItem(
+  item: SavedPost,
+  isSaved: suspend (SavedPost) -> Boolean,
+  postActions: PostActions,
+  modifier: Modifier = Modifier,
+) {
+  val saved by produceState(false, item) { value = isSaved(item) }
+  LobstersCard(
+    post = item,
+    isSaved = saved,
+    postActions = postActions,
+    modifier = modifier,
+  )
+}

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/lists/NetworkPosts.kt

@@ -27,18 +27,19 @@ import androidx.compose.ui.unit.dp
 import androidx.paging.LoadState
 import androidx.paging.compose.LazyPagingItems
 import androidx.paging.compose.items
-import dev.msfjarvis.claw.common.posts.LobstersCard
 import dev.msfjarvis.claw.common.posts.PostActions
 import dev.msfjarvis.claw.common.posts.toDbModel
 import dev.msfjarvis.claw.common.ui.NetworkError
 import dev.msfjarvis.claw.common.ui.ProgressBar
+import dev.msfjarvis.claw.database.local.SavedPost
 import dev.msfjarvis.claw.model.LobstersPost
 
 @OptIn(ExperimentalMaterialApi::class)
 @Composable
 fun NetworkPosts(
-  lazyPagingItems: LazyPagingItems<Pair<LobstersPost, Boolean>>,
+  lazyPagingItems: LazyPagingItems<LobstersPost>,
   listState: LazyListState,
+  isPostSaved: suspend (SavedPost) -> Boolean,
   postActions: PostActions,
   modifier: Modifier = Modifier,
 ) {
@@ -58,10 +59,10 @@ fun NetworkPosts(
       ) {
         items(lazyPagingItems) { item ->
           if (item != null) {
-            val (post, saved) = item
-            LobstersCard(
-              post = post.toDbModel(),
-              isSaved = saved,
+            val dbModel = item.toDbModel()
+            ListItem(
+              item = dbModel,
+              isSaved = isPostSaved,
               postActions = postActions,
             )
 

android/src/main/kotlin/dev/msfjarvis/claw/android/viewmodel/ClawViewModel.kt

@@ -10,8 +10,6 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.paging.Pager
 import androidx.paging.PagingConfig
-import androidx.paging.cachedIn
-import androidx.paging.map
 import com.deliveryhero.whetstone.viewmodel.ContributesViewModel
 import com.slack.eithernet.ApiResult.Failure
 import com.slack.eithernet.ApiResult.Success
@@ -45,16 +43,10 @@ constructor(
     Pager(PagingConfig(pageSize = 20)) { pagingSourceFactory.create(api::getHottestPosts) }
 
   val hottestPosts
-    get() =
-      hottestPostsPager.flow
-        .map { pagingData -> pagingData.map { item -> item to isPostSaved(item.shortId) } }
-        .cachedIn(viewModelScope)
+    get() = hottestPostsPager.flow
 
   val newestPosts
-    get() =
-      newestPostsPager.flow
-        .map { pagingData -> pagingData.map { item -> item to isPostSaved(item.shortId) } }
-        .cachedIn(viewModelScope)
+    get() = newestPostsPager.flow
 
   private val savedPostsFlow
     get() = savedPostsRepository.savedPosts
@@ -67,13 +59,13 @@ constructor(
     return sorted.groupBy { post -> post.createdAt.toLocalDateTime().month }
   }
 
-  private suspend fun isPostSaved(shortId: String): Boolean {
-    return savedPostsFlow.first().any { savedPost -> savedPost.shortId == shortId }
+  suspend fun isPostSaved(post: SavedPost): Boolean {
+    return savedPostsFlow.first().any { savedPost -> savedPost.shortId == post.shortId }
   }
 
   fun toggleSave(post: SavedPost) {
     viewModelScope.launch(ioDispatcher) {
-      val saved = isPostSaved(post.shortId)
+      val saved = isPostSaved(post)
       if (saved) {
         savedPostsRepository.removePost(post)
       } else {