Convert DragAndDropDiffer.submitList to coroutines

app/src/main/java/com/todoroo/astrid/activity/TaskListFragment.kt

@@ -21,7 +21,6 @@ import androidx.appcompat.widget.Toolbar
 import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
-import androidx.lifecycle.Observer
 import androidx.lifecycle.lifecycleScope
 import androidx.paging.PagedList
 import androidx.recyclerview.widget.DefaultItemAnimator
@@ -202,18 +201,18 @@ class TaskListFragment : Fragment(), OnRefreshListener, Toolbar.OnMenuItemClickL
         listViewModel.setFilter((if (searchQuery == null) filter else createSearchFilter(searchQuery!!)))
         (recyclerView.itemAnimator as DefaultItemAnimator).supportsChangeAnimations = false
         recyclerView.layoutManager = LinearLayoutManager(context)
-        listViewModel.observe(
-                this,
-                Observer { list: List<TaskContainer> ->
-                    submitList(list)
-                    if (list.isEmpty()) {
-                        swipeRefreshLayout.visibility = View.GONE
-                        emptyRefreshLayout.visibility = View.VISIBLE
-                    } else {
-                        swipeRefreshLayout.visibility = View.VISIBLE
-                        emptyRefreshLayout.visibility = View.GONE
-                    }
-                })
+        listViewModel.observe(this) {
+            lifecycleScope.launch {
+                submitList(it)
+                if (it.isEmpty()) {
+                    swipeRefreshLayout.visibility = View.GONE
+                    emptyRefreshLayout.visibility = View.VISIBLE
+                } else {
+                    swipeRefreshLayout.visibility = View.VISIBLE
+                    emptyRefreshLayout.visibility = View.GONE
+                }
+            }
+        }
         setupRefresh(swipeRefreshLayout)
         setupRefresh(emptyRefreshLayout)
         toolbar.title = filter.listingTitle
@@ -224,7 +223,7 @@ class TaskListFragment : Fragment(), OnRefreshListener, Toolbar.OnMenuItemClickL
         return parent
     }
 
-    private fun submitList(tasks: List<TaskContainer>) {
+    private suspend fun submitList(tasks: List<TaskContainer>) {
         if (tasks is PagedList<*>) {
             if (recyclerAdapter !is PagedListRecyclerAdapter) {
                 setAdapter(

app/src/main/java/org/tasks/activities/DragAndDropDiffer.kt

@@ -3,11 +3,12 @@ package org.tasks.activities
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListUpdateCallback
 import com.todoroo.andlib.utility.AndroidUtilities
-import io.reactivex.Single
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.schedulers.Schedulers
 import io.reactivex.subjects.PublishSubject
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 import java.util.*
 
 interface DragAndDropDiffer<T, R> : ListUpdateCallback {
@@ -17,11 +18,11 @@ interface DragAndDropDiffer<T, R> : ListUpdateCallback {
     var items: R
     var dragging: Boolean
 
-    fun submitList(list: List<T>) {
-        disposables.add(
-                Single.fromCallable { transform(list) }
-                        .subscribeOn(Schedulers.computation())
-                        .subscribe(publishSubject::onNext))
+    suspend fun submitList(list: List<T>) {
+        val transform = withContext(Dispatchers.Default) {
+            transform(list)
+        }
+        publishSubject.onNext(transform)
     }
 
     fun calculateDiff(last: Pair<R, DiffUtil.DiffResult?>, next: R): Pair<R, DiffUtil.DiffResult?> {

app/src/main/java/org/tasks/activities/NavigationDrawerCustomization.kt

@@ -90,7 +90,7 @@ class NavigationDrawerCustomization : ThemedInjectingAppCompatActivity(), Toolba
         filterProvider
                 .drawerCustomizationItems()
                 .onEach { f -> f.count = 0 }
-                .apply(adapter::submitList)
+                .let { adapter.submitList(it) }
     }
 
     private fun onClick(item: FilterListItem?) {

app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.kt

@@ -61,7 +61,9 @@ class DragAndDropRecyclerAdapter(
 
     override fun getItemViewType(position: Int) = if (items.isHeader(position)) 1 else 0
 
-    override fun submitList(list: List<TaskContainer>) = super.submitList(list)
+    override suspend fun submitList(list: List<TaskContainer>) {
+        super.submitList(list)
+    }
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder = if (viewType == 1) {
         viewHolderFactory.newHeaderViewHolder(parent, this::toggleGroup)

app/src/main/java/org/tasks/tasklist/PagedListRecyclerAdapter.kt

@@ -22,7 +22,7 @@ class PagedListRecyclerAdapter(
 
     override fun getItem(position: Int) = differ.getItem(position)
 
-    override fun submitList(list: List<TaskContainer>) = differ.submitList(list as PagedList<TaskContainer>)
+    override suspend fun submitList(list: List<TaskContainer>) = differ.submitList(list as PagedList<TaskContainer>)
 
     override fun onMoved(fromPosition: Int, toPosition: Int) {
         val recyclerViewState = recyclerView.layoutManager!!.onSaveInstanceState()

app/src/main/java/org/tasks/tasklist/TaskListRecyclerAdapter.kt

@@ -44,7 +44,7 @@ abstract class TaskListRecyclerAdapter internal constructor(
 
     abstract fun dragAndDropEnabled(): Boolean
 
-    abstract fun submitList(list: List<TaskContainer>)
+    abstract suspend fun submitList(list: List<TaskContainer>)
 
     override fun onInserted(position: Int, count: Int) {
         notifyItemRangeInserted(position, count)

app/src/main/java/org/tasks/ui/NavigationDrawerFragment.kt

@@ -13,7 +13,6 @@ import android.view.ViewGroup
 import androidx.drawerlayout.widget.DrawerLayout
 import androidx.drawerlayout.widget.DrawerLayout.SimpleDrawerListener
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.lifecycleScope
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -141,7 +140,7 @@ class NavigationDrawerFragment : Fragment() {
                         it.count = taskDao.count(it)
                     }
                 }
-                .apply(adapter::submitList)
+                .let { adapter.submitList(it) }
     }
 
     private inner class RefreshReceiver : BroadcastReceiver() {

app/src/main/java/org/tasks/ui/SubtaskControlSet.kt

@@ -16,7 +16,6 @@ import android.widget.EditText
 import android.widget.LinearLayout
 import androidx.core.widget.addTextChangedListener
 import androidx.fragment.app.viewModels
-import androidx.lifecycle.Observer
 import androidx.lifecycle.lifecycleScope
 import androidx.recyclerview.widget.DefaultItemAnimator
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -85,7 +84,9 @@ class SubtaskControlSet : TaskEditControlFragment(), SubtaskViewHolder.Callbacks
                 (recyclerView.itemAnimator as DefaultItemAnimator).supportsChangeAnimations = false
                 recyclerView.layoutManager = LinearLayoutManager(activity)
                 recyclerView.isNestedScrollingEnabled = false
-                listViewModel.observe(this, Observer { list: List<TaskContainer?>? -> recyclerAdapter.submitList(list) })
+                listViewModel.observe(this) {
+                    list: List<TaskContainer?>? -> recyclerAdapter.submitList(list)
+                }
                 recyclerView.adapter = recyclerAdapter
             }
         }

app/src/main/java/org/tasks/ui/TaskListViewModel.kt

@@ -38,7 +38,7 @@ class TaskListViewModel @ViewModelInject constructor(
                 || filter.supportsAstridSorting() && preferences.isAstridSort)
     }
 
-    fun observe(owner: LifecycleOwner, observer: Observer<List<TaskContainer>>) =
+    fun observe(owner: LifecycleOwner, observer: (List<TaskContainer>) -> Unit) =
             tasks.observe(owner, observer)
 
     fun searchByFilter(filter: Filter?) {