drag to reorder Category list

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

@@ -5,12 +5,17 @@ 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
@@ -18,6 +23,8 @@ 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,
+    moveTo: (Category, Int) -> Unit,
-    onClickMoveDown: (Category) -> Unit,
     navigateUp: () -> Unit,
 ) {
     val lazyListState = rememberLazyListState()
@@ -81,8 +87,7 @@ fun CategoryScreen(
                 PaddingValues(horizontal = MaterialTheme.padding.medium),
             onClickRename = onClickRename,
             onClickDelete = onClickDelete,
-            onMoveUp = onClickMoveUp,
+            moveTo = moveTo,
-            onMoveDown = onClickMoveDown,
         )
     }
 }
@@ -94,28 +99,41 @@ private fun CategoryContent(
     paddingValues: PaddingValues,
     onClickRename: (Category) -> Unit,
     onClickDelete: (Category) -> Unit,
-    onMoveUp: (Category) -> Unit,
+    moveTo: (Category, Int) -> Unit,
-    onMoveDown: (Category) -> Unit,
 ) {
+    var reorderableList by remember { mutableStateOf(categories.toList()) }
+    val reorderableLazyColumnState = rememberReorderableLazyListState(lazyListState) { from, to ->
+        reorderableList = reorderableList.toMutableList().apply {
+            moveTo(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(
-            items = categories,
+            items = reorderableList,
-            key = { _, category -> "category-${category.id}" },
+            key = { category -> category.key() },
-        ) { index, category ->
+        ) { category ->
+            ReorderableItem(reorderableLazyColumnState, category.key()) {
                 CategoryListItem(
                     modifier = Modifier.animateItem(),
                     category = category,
-                canMoveUp = index != 0,
-                canMoveDown = index != categories.lastIndex,
-                onMoveUp = onMoveUp,
-                onMoveDown = onMoveDown,
                     onRename = { onClickRename(category) },
                     onDelete = { onClickDelete(category) },
                 )
             }
         }
     }
+}
+
+fun Category.key() = "category-$id"

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

@@ -2,15 +2,12 @@ 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.Edit
+import androidx.compose.material.icons.rounded.DragHandle
 import androidx.compose.material3.ElevatedCard
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -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 +36,22 @@ fun CategoryListItem(
             modifier = Modifier
                 .fillMaxWidth()
                 .clickable { onRename() }
-                .padding(
+                .padding(MaterialTheme.padding.medium),
-                    start = MaterialTheme.padding.medium,
-                    top = MaterialTheme.padding.medium,
-                    end = MaterialTheme.padding.medium,
-                ),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Icon(imageVector = Icons.AutoMirrored.Outlined.Label, contentDescription = null)
+            IconButton(
+                modifier = Modifier
+                    .draggableHandle(),
+                onClick = {},
+            ) {
+                Icon(Icons.Rounded.DragHandle, contentDescription = "Reorder")
+            }
             Text(
                 text = category.name,
                 modifier = Modifier
+                    .weight(1f)
                     .padding(start = MaterialTheme.padding.medium),
             )
-        }
-        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,
+            moveTo = screenModel::moveTo,
-            onClickMoveDown = screenModel::moveDown,
             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 moveTo(category: Category, offset: Int) {
         screenModelScope.launch {
-            when (reorderCategory.moveUp(category)) {
+            when (reorderCategory.await(category, offset)) {
-                is ReorderCategory.Result.InternalError -> _events.send(CategoryEvent.InternalError)
-                else -> {}
-            }
-        }
-    }
-
-    fun moveDown(category: Category) {
-        screenModelScope.launch {
-            when (reorderCategory.moveDown(category)) {
                 is ReorderCategory.Result.InternalError -> _events.send(CategoryEvent.InternalError)
                 else -> {}
             }

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

@@ -8,7 +8,6 @@ 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,
@@ -16,11 +15,7 @@ class ReorderCategory(
 
     private val mutex = Mutex()
 
-    suspend fun moveUp(category: Category): Result = await(category, MoveTo.UP)
+    suspend fun await(category: Category, offset: Int) = withNonCancellableContext {
-
-    suspend fun moveDown(category: Category): Result = await(category, MoveTo.DOWN)
-
-    private suspend fun await(category: Category, moveTo: MoveTo) = withNonCancellableContext {
         mutex.withLock {
             val categories = categoryRepository.getAll()
                 .filterNot(Category::isSystemCategory)
@@ -31,13 +26,10 @@ class ReorderCategory(
                 return@withNonCancellableContext Result.Unchanged
             }
 
-            val newPosition = when (moveTo) {
+            val newPosition = currentIndex + offset
-                MoveTo.UP -> currentIndex - 1
-                MoveTo.DOWN -> currentIndex + 1
-            }.toInt()
 
             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"