Drag-Drop reordering category

app/build.gradle.kts

@@ -260,6 +260,7 @@ dependencies {
     implementation(libs.swipe)
     implementation(libs.compose.webview)
     implementation(libs.compose.grid)
+    implementation(libs.reorderable)
 
     // Logging
     implementation(libs.logcat)

app/src/main/java/eu/kanade/presentation/category/CategoryScreen.kt

@@ -5,19 +5,26 @@ import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
-import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.outlined.SortByAlpha
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+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 eu.kanade.presentation.category.components.CategoryFloatingActionButton
 import eu.kanade.presentation.category.components.CategoryListItem
 import eu.kanade.presentation.components.AppBar
 import eu.kanade.presentation.components.AppBarActions
 import eu.kanade.tachiyomi.ui.category.CategoryScreenState
 import kotlinx.collections.immutable.persistentListOf
+import sh.calvin.reorderable.ReorderableItem
+import sh.calvin.reorderable.rememberReorderableLazyListState
 import tachiyomi.domain.category.model.Category
 import tachiyomi.i18n.MR
 import tachiyomi.presentation.core.components.material.Scaffold
@@ -34,8 +41,7 @@ fun CategoryScreen(
     onClickSortAlphabetically: () -> Unit,
     onClickRename: (Category) -> Unit,
     onClickDelete: (Category) -> Unit,
-    onClickMoveUp: (Category) -> Unit,
-    onClickMoveDown: (Category) -> Unit,
+    changeOrder: (Category, Int) -> Unit,
     navigateUp: () -> Unit,
 ) {
     val lazyListState = rememberLazyListState()
@@ -81,8 +87,7 @@ fun CategoryScreen(
                 PaddingValues(horizontal = MaterialTheme.padding.medium),
             onClickRename = onClickRename,
             onClickDelete = onClickDelete,
-            onMoveUp = onClickMoveUp,
-            onMoveDown = onClickMoveDown,
+            changeOrder = changeOrder,
         )
     }
 }
@@ -94,28 +99,41 @@ private fun CategoryContent(
     paddingValues: PaddingValues,
     onClickRename: (Category) -> Unit,
     onClickDelete: (Category) -> Unit,
-    onMoveUp: (Category) -> Unit,
-    onMoveDown: (Category) -> Unit,
+    changeOrder: (Category, Int) -> Unit,
 ) {
+    var reorderableList by remember { mutableStateOf(categories.toList()) }
+    val reorderableLazyColumnState = rememberReorderableLazyListState(lazyListState) { from, to ->
+        reorderableList = reorderableList.toMutableList().apply {
+            changeOrder(reorderableList[from.index], to.index - from.index)
+            add(to.index, removeAt(from.index))
+        }
+    }
+
+    LaunchedEffect(categories) {
+        if (!reorderableLazyColumnState.isAnyItemDragging) {
+            reorderableList = categories.toList()
+        }
+    }
+
     LazyColumn(
         state = lazyListState,
         contentPadding = paddingValues,
         verticalArrangement = Arrangement.spacedBy(MaterialTheme.padding.small),
     ) {
-        itemsIndexed(
-            items = categories,
-            key = { _, category -> "category-${category.id}" },
-        ) { index, category ->
-            CategoryListItem(
-                modifier = Modifier.animateItem(),
-                category = category,
-                canMoveUp = index != 0,
-                canMoveDown = index != categories.lastIndex,
-                onMoveUp = onMoveUp,
-                onMoveDown = onMoveDown,
-                onRename = { onClickRename(category) },
-                onDelete = { onClickDelete(category) },
-            )
+        items(
+            items = reorderableList,
+            key = { category -> category.key },
+        ) { category ->
+            ReorderableItem(reorderableLazyColumnState, category.key) {
+                CategoryListItem(
+                    modifier = Modifier.animateItem(),
+                    category = category,
+                    onRename = { onClickRename(category) },
+                    onDelete = { onClickDelete(category) },
+                )
+            }
         }
     }
 }
+
+private val Category.key get() = "category-$id"

app/src/main/java/eu/kanade/presentation/category/components/CategoryListItem.kt

@@ -2,14 +2,11 @@ package eu.kanade.presentation.category.components
 
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.automirrored.outlined.Label
-import androidx.compose.material.icons.outlined.ArrowDropDown
-import androidx.compose.material.icons.outlined.ArrowDropUp
 import androidx.compose.material.icons.outlined.Delete
+import androidx.compose.material.icons.outlined.DragHandle
 import androidx.compose.material.icons.outlined.Edit
 import androidx.compose.material3.ElevatedCard
 import androidx.compose.material3.Icon
@@ -19,18 +16,15 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import sh.calvin.reorderable.ReorderableCollectionItemScope
 import tachiyomi.domain.category.model.Category
 import tachiyomi.i18n.MR
 import tachiyomi.presentation.core.components.material.padding
 import tachiyomi.presentation.core.i18n.stringResource
 
 @Composable
-fun CategoryListItem(
+fun ReorderableCollectionItemScope.CategoryListItem(
     category: Category,
-    canMoveUp: Boolean,
-    canMoveDown: Boolean,
-    onMoveUp: (Category) -> Unit,
-    onMoveDown: (Category) -> Unit,
     onRename: () -> Unit,
     onDelete: () -> Unit,
     modifier: Modifier = Modifier,
@@ -42,34 +36,25 @@ fun CategoryListItem(
             modifier = Modifier
                 .fillMaxWidth()
                 .clickable { onRename() }
+                .padding(vertical = MaterialTheme.padding.small)
                 .padding(
-                    start = MaterialTheme.padding.medium,
-                    top = MaterialTheme.padding.medium,
+                    start = MaterialTheme.padding.small,
                     end = MaterialTheme.padding.medium,
                 ),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Icon(imageVector = Icons.AutoMirrored.Outlined.Label, contentDescription = null)
+            Icon(
+                imageVector = Icons.Outlined.DragHandle,
+                contentDescription = null,
+                modifier = Modifier
+                    .padding(MaterialTheme.padding.medium)
+                    .draggableHandle(),
+            )
             Text(
                 text = category.name,
                 modifier = Modifier
-                    .padding(start = MaterialTheme.padding.medium),
+                    .weight(1f),
             )
-        }
-        Row {
-            IconButton(
-                onClick = { onMoveUp(category) },
-                enabled = canMoveUp,
-            ) {
-                Icon(imageVector = Icons.Outlined.ArrowDropUp, contentDescription = null)
-            }
-            IconButton(
-                onClick = { onMoveDown(category) },
-                enabled = canMoveDown,
-            ) {
-                Icon(imageVector = Icons.Outlined.ArrowDropDown, contentDescription = null)
-            }
-            Spacer(modifier = Modifier.weight(1f))
             IconButton(onClick = onRename) {
                 Icon(
                     imageVector = Icons.Outlined.Edit,

app/src/main/java/eu/kanade/tachiyomi/ui/category/CategoryScreen.kt

@@ -43,8 +43,7 @@ class CategoryScreen : Screen() {
             onClickSortAlphabetically = { screenModel.showDialog(CategoryDialog.SortAlphabetically) },
             onClickRename = { screenModel.showDialog(CategoryDialog.Rename(it)) },
             onClickDelete = { screenModel.showDialog(CategoryDialog.Delete(it)) },
-            onClickMoveUp = screenModel::moveUp,
-            onClickMoveDown = screenModel::moveDown,
+            changeOrder = screenModel::changeOrder,
             navigateUp = navigator::pop,
         )
 

app/src/main/java/eu/kanade/tachiyomi/ui/category/CategoryScreenModel.kt

@@ -74,18 +74,9 @@ class CategoryScreenModel(
         }
     }
 
-    fun moveUp(category: Category) {
+    fun changeOrder(category: Category, newOrder: Int) {
         screenModelScope.launch {
-            when (reorderCategory.moveUp(category)) {
-                is ReorderCategory.Result.InternalError -> _events.send(CategoryEvent.InternalError)
-                else -> {}
-            }
-        }
-    }
-
-    fun moveDown(category: Category) {
-        screenModelScope.launch {
-            when (reorderCategory.moveDown(category)) {
+            when (reorderCategory.changeOrder(category, newOrder)) {
                 is ReorderCategory.Result.InternalError -> _events.send(CategoryEvent.InternalError)
                 else -> {}
             }

domain/src/main/java/tachiyomi/domain/category/interactor/ReorderCategory.kt

@@ -8,19 +8,14 @@ import tachiyomi.core.common.util.system.logcat
 import tachiyomi.domain.category.model.Category
 import tachiyomi.domain.category.model.CategoryUpdate
 import tachiyomi.domain.category.repository.CategoryRepository
-import java.util.Collections
 
 class ReorderCategory(
     private val categoryRepository: CategoryRepository,
 ) {
 
     private val mutex = Mutex()
 
-    suspend fun moveUp(category: Category): Result = await(category, MoveTo.UP)
-
-    suspend fun moveDown(category: Category): Result = await(category, MoveTo.DOWN)
-
-    private suspend fun await(category: Category, moveTo: MoveTo) = withNonCancellableContext {
+    suspend fun changeOrder(category: Category, newOrder: Int) = withNonCancellableContext {
         mutex.withLock {
             val categories = categoryRepository.getAll()
                 .filterNot(Category::isSystemCategory)
@@ -31,13 +26,10 @@ class ReorderCategory(
                 return@withNonCancellableContext Result.Unchanged
             }
 
-            val newPosition = when (moveTo) {
-                MoveTo.UP -> currentIndex - 1
-                MoveTo.DOWN -> currentIndex + 1
-            }.toInt()
+            val newPosition = currentIndex + newOrder
 
             try {
-                Collections.swap(categories, currentIndex, newPosition)
+                categories.add(newPosition, categories.removeAt(currentIndex))
 
                 val updates = categories.mapIndexed { index, category ->
                     CategoryUpdate(
@@ -81,9 +73,4 @@ class ReorderCategory(
         data object Unchanged : Result
         data class InternalError(val error: Throwable) : Result
     }
-
-    private enum class MoveTo {
-        UP,
-        DOWN,
-    }
 }

gradle/libs.versions.toml

@@ -65,6 +65,7 @@ compose-materialmotion = "io.github.fornewid:material-motion-compose-core:2.0.1"
 compose-webview = "io.github.kevinnzou:compose-webview:0.33.6"
 compose-grid = "io.woong.compose.grid:grid:1.2.2"
 compose-stablemarker = "com.github.skydoves:compose-stable-marker:1.0.5"
+reorderable = { module = "sh.calvin.reorderable:reorderable", version = "2.4.0" }
 
 swipe = "me.saket.swipe:swipe:1.3.0"