Fix favourites categories

app/src/main/java/org/koitharu/kotatsu/favourites/domain/FavouritesRepository.kt

@@ -4,6 +4,7 @@ import androidx.collection.ArraySet
 import androidx.room.withTransaction
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.withContext
 import org.koitharu.kotatsu.core.db.MangaDatabase
@@ -61,13 +62,13 @@ class FavouritesRepository(private val db: MangaDatabase) {
 	fun observeCategories(): Flow<List<FavouriteCategory>> {
 		return db.favouriteCategoriesDao.observeAll().mapItems {
 			it.toFavouriteCategory()
-		}
+		}.distinctUntilChanged()
 	}
 
 	fun observeCategories(mangaId: Long): Flow<List<FavouriteCategory>> {
 		return db.favouritesDao.observe(mangaId).map { entity ->
 			entity?.categories?.map { it.toFavouriteCategory() }.orEmpty()
-		}
+		}.distinctUntilChanged()
 	}
 
 	fun observeCategoriesIds(mangaId: Long): Flow<List<Long>> {

app/src/main/java/org/koitharu/kotatsu/favourites/ui/FavouritesContainerFragment.kt

@@ -26,6 +26,7 @@ class FavouritesContainerFragment : BaseFragment<FragmentFavouritesBinding>(),
 	private val editDelegate by lazy(LazyThreadSafetyMode.NONE) {
 		CategoriesEditDelegate(requireContext(), this)
 	}
+	private var pagerAdapter: FavouritesPagerAdapter? = null
 
 	override fun onCreate(savedInstanceState: Bundle?) {
 		super.onCreate(savedInstanceState)
@@ -40,13 +41,22 @@ class FavouritesContainerFragment : BaseFragment<FragmentFavouritesBinding>(),
 	override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
 		super.onViewCreated(view, savedInstanceState)
 		val adapter = FavouritesPagerAdapter(this, this)
+		viewModel.categories.value?.let {
+			adapter.replaceData(wrapCategories(it))
+		}
 		binding.pager.adapter = adapter
+		pagerAdapter = adapter
 		TabLayoutMediator(binding.tabs, binding.pager, adapter).attach()
 
 		viewModel.categories.observe(viewLifecycleOwner, ::onCategoriesChanged)
 		viewModel.onError.observe(viewLifecycleOwner, ::onError)
 	}
 
+	override fun onDestroyView() {
+		pagerAdapter = null
+		super.onDestroyView()
+	}
+
 	override fun onWindowInsetsChanged(insets: Insets) {
 		binding.tabs.updatePadding(
 			left = insets.left,
@@ -55,10 +65,7 @@ class FavouritesContainerFragment : BaseFragment<FragmentFavouritesBinding>(),
 	}
 
 	private fun onCategoriesChanged(categories: List<FavouriteCategory>) {
-		val data = ArrayList<FavouriteCategory>(categories.size + 1)
-		data += FavouriteCategory(0L, getString(R.string.all_favourites), -1, Date())
-		data += categories
-		(binding.pager.adapter as? FavouritesPagerAdapter)?.replaceData(data)
+		pagerAdapter?.replaceData(wrapCategories(categories))
 	}
 
 	override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
@@ -109,6 +116,13 @@ class FavouritesContainerFragment : BaseFragment<FragmentFavouritesBinding>(),
 		viewModel.createCategory(name)
 	}
 
+	private fun wrapCategories(categories: List<FavouriteCategory>): List<FavouriteCategory> {
+		val data = ArrayList<FavouriteCategory>(categories.size + 1)
+		data += FavouriteCategory(0L, getString(R.string.all_favourites), -1, Date())
+		data += categories
+		return data
+	}
+
 	companion object {
 
 		fun newInstance() = FavouritesContainerFragment()

app/src/main/java/org/koitharu/kotatsu/favourites/ui/FavouritesPagerAdapter.kt

@@ -2,44 +2,55 @@ package org.koitharu.kotatsu.favourites.ui
 
 import android.view.View
 import androidx.fragment.app.Fragment
+import androidx.recyclerview.widget.AsyncListDiffer
+import androidx.recyclerview.widget.DiffUtil
 import androidx.viewpager2.adapter.FragmentStateAdapter
 import com.google.android.material.tabs.TabLayout
 import com.google.android.material.tabs.TabLayoutMediator
-import org.koitharu.kotatsu.base.ui.list.AdapterUpdater
 import org.koitharu.kotatsu.core.model.FavouriteCategory
 import org.koitharu.kotatsu.favourites.ui.list.FavouritesListFragment
-import org.koitharu.kotatsu.utils.ext.replaceWith
 
 class FavouritesPagerAdapter(
 	fragment: Fragment,
 	private val longClickListener: FavouritesTabLongClickListener
-) : FragmentStateAdapter(fragment),
+) : FragmentStateAdapter(fragment.childFragmentManager, fragment.viewLifecycleOwner.lifecycle),
 	TabLayoutMediator.TabConfigurationStrategy, View.OnLongClickListener {
 
-	private val dataSet = ArrayList<FavouriteCategory>()
+	private val differ = AsyncListDiffer(this, DiffCallback())
 
-	override fun getItemCount() = dataSet.size
+	override fun getItemCount() = differ.currentList.size
 
 	override fun createFragment(position: Int): Fragment {
-		val item = dataSet[position]
+		val item = differ.currentList[position]
 		return FavouritesListFragment.newInstance(item.id)
 	}
 
 	override fun onConfigureTab(tab: TabLayout.Tab, position: Int) {
-		val item = dataSet[position]
+		val item = differ.currentList[position]
 		tab.text = item.title
 		tab.view.tag = item
 		tab.view.setOnLongClickListener(this)
 	}
 
 	fun replaceData(data: List<FavouriteCategory>) {
-		val updater = AdapterUpdater(dataSet, data, FavouriteCategory::id)
-		dataSet.replaceWith(data)
-		updater(this)
+		differ.submitList(data)
 	}
 
 	override fun onLongClick(v: View): Boolean {
 		val item = v.tag as? FavouriteCategory ?: return false
 		return longClickListener.onTabLongClick(v, item)
 	}
+
+	private class DiffCallback : DiffUtil.ItemCallback<FavouriteCategory>() {
+
+		override fun areItemsTheSame(
+			oldItem: FavouriteCategory,
+			newItem: FavouriteCategory
+		): Boolean = oldItem.id == newItem.id
+
+		override fun areContentsTheSame(
+			oldItem: FavouriteCategory,
+			newItem: FavouriteCategory
+		): Boolean = oldItem.id == newItem.id && oldItem.title == newItem.title
+	}
 }

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/CategoriesActivity.kt

@@ -93,8 +93,6 @@ class CategoriesActivity : BaseActivity<ActivityCategoriesBinding>(),
 	}
 
 	private fun onCategoriesChanged(categories: List<FavouriteCategory>) {
-		// TODO check if not moved
-
 		adapter.items = categories
 		binding.textViewHolder.isVisible = categories.isEmpty()
 	}
@@ -124,14 +122,22 @@ class CategoriesActivity : BaseActivity<ActivityCategoriesBinding>(),
 			recyclerView: RecyclerView,
 			viewHolder: RecyclerView.ViewHolder,
 			target: RecyclerView.ViewHolder
-		): Boolean {
-			val oldPos = viewHolder.bindingAdapterPosition
-			val newPos = target.bindingAdapterPosition
-			viewModel.reorderCategories(oldPos, newPos)
-			return true
-		}
+		): Boolean = true
 
 		override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) = Unit
+
+		override fun onMoved(
+			recyclerView: RecyclerView,
+			viewHolder: RecyclerView.ViewHolder,
+			fromPos: Int,
+			target: RecyclerView.ViewHolder,
+			toPos: Int,
+			x: Int,
+			y: Int
+		) {
+			super.onMoved(recyclerView, viewHolder, fromPos, target, toPos, x, y)
+			viewModel.reorderCategories(fromPos, toPos)
+		}
 	}
 
 	companion object {

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/CategoriesAdapter.kt

@@ -4,7 +4,6 @@ import androidx.recyclerview.widget.DiffUtil
 import com.hannesdorfmann.adapterdelegates4.AsyncListDifferDelegationAdapter
 import org.koitharu.kotatsu.base.ui.list.OnListItemClickListener
 import org.koitharu.kotatsu.core.model.FavouriteCategory
-import kotlin.jvm.internal.Intrinsics
 
 class CategoriesAdapter(
 	onItemClickListener: OnListItemClickListener<FavouriteCategory>
@@ -26,7 +25,7 @@ class CategoriesAdapter(
 		}
 
 		override fun areContentsTheSame(oldItem: FavouriteCategory, newItem: FavouriteCategory): Boolean {
-			return Intrinsics.areEqual(oldItem, newItem)
+			return oldItem.id == newItem.id && oldItem.title == newItem.title
 		}
 	}
 }

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/FavouritesCategoriesViewModel.kt

@@ -6,6 +6,8 @@ import kotlinx.coroutines.Job
 import org.koitharu.kotatsu.base.ui.BaseViewModel
 import org.koitharu.kotatsu.favourites.domain.FavouritesRepository
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
+import java.util.*
+import kotlin.collections.ArrayList
 
 class FavouritesCategoriesViewModel(
 	private val repository: FavouritesRepository
@@ -40,8 +42,7 @@ class FavouritesCategoriesViewModel(
 			prevJob?.join()
 			val items = categories.value ?: error("This should not happen")
 			val ids = items.mapTo(ArrayList(items.size)) { it.id }
-			val item = ids.removeAt(oldPos)
-			ids.add(newPos, item)
+			Collections.swap(ids, oldPos, newPos)
 			repository.reorderCategories(ids)
 		}
 	}

app/src/main/java/org/koitharu/kotatsu/favourites/ui/list/FavouritesListViewModel.kt

@@ -14,7 +14,6 @@ import org.koitharu.kotatsu.list.ui.model.LoadingState
 import org.koitharu.kotatsu.list.ui.model.toErrorState
 import org.koitharu.kotatsu.list.ui.model.toUi
 import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
-import org.koitharu.kotatsu.utils.ext.onFirst
 
 class FavouritesListViewModel(
 	private val categoryId: Long,
@@ -38,8 +37,6 @@ class FavouritesListViewModel(
 			)
 			else -> list.toUi(mode)
 		}
-	}.onFirst {
-		isLoading.postValue(false)
 	}.catch {
 		emit(listOf(it.toErrorState(canRetry = false)))
 	}.asLiveDataDistinct(viewModelScope.coroutineContext + Dispatchers.Default, listOf(LoadingState))