Convert task adapters to Kotlin

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

@@ -182,7 +182,7 @@ class TaskListFragment : InjectingFragment(), OnRefreshListener, Toolbar.OnMenuI
 
     override fun onSaveInstanceState(outState: Bundle) {
         super.onSaveInstanceState(outState)
-        val selectedTaskIds: List<Long> = taskAdapter.selected
+        val selectedTaskIds: List<Long> = taskAdapter.getSelected()
         outState.putLongArray(EXTRA_SELECTED_TASK_IDS, selectedTaskIds.toLongArray())
         outState.putString(EXTRA_SEARCH, searchQuery)
     }
@@ -492,7 +492,7 @@ class TaskListFragment : InjectingFragment(), OnRefreshListener, Toolbar.OnMenuI
         loadTaskListContent()
     }
 
-    fun onTaskCreated(uuid: String?) {
+    fun onTaskCreated(uuid: String) {
         taskAdapter.onTaskCreated(uuid)
     }
 
@@ -522,7 +522,7 @@ class TaskListFragment : InjectingFragment(), OnRefreshListener, Toolbar.OnMenuI
             }
             REQUEST_MOVE_TASKS -> if (resultCode == Activity.RESULT_OK) {
                 taskMover.move(
-                        taskAdapter.selected,
+                        taskAdapter.getSelected(),
                         data!!.getParcelableExtra(RemoteListPicker.EXTRA_SELECTED_FILTER))
                 finishActionMode()
             }
@@ -605,7 +605,7 @@ class TaskListFragment : InjectingFragment(), OnRefreshListener, Toolbar.OnMenuI
     }
 
     override fun onActionItemClicked(mode: ActionMode, item: MenuItem): Boolean {
-        val selected = taskAdapter.selected
+        val selected = taskAdapter.getSelected()
         return when (item.itemId) {
             R.id.edit_tags -> {
                 val tags = tagDataDao.getTagSelections(selected)
@@ -632,10 +632,9 @@ class TaskListFragment : InjectingFragment(), OnRefreshListener, Toolbar.OnMenuI
                 true
             }
             R.id.menu_share -> {
-                send(
+                DbUtils
-                        DbUtils.collect(
+                        .collect(selected) { taskDao.fetchTasks(preferences, IdListFilter(it)) }
-                                taskAdapter.selected
+                        .apply(this::send)
-                        ) { ids: List<Long?>? -> taskDao.fetchTasks(preferences, IdListFilter(ids)) })
                 true
             }
             R.id.delete -> {

app/src/main/java/com/todoroo/astrid/adapter/AstridTaskAdapter.java

@@ -1,145 +0,0 @@
-package com.todoroo.astrid.adapter;
-
-import static org.tasks.Strings.isNullOrEmpty;
-
-import com.todoroo.andlib.utility.DateUtilities;
-import com.todoroo.astrid.api.Filter;
-import com.todoroo.astrid.dao.TaskDao;
-import com.todoroo.astrid.data.Task;
-import com.todoroo.astrid.subtasks.SubtasksFilterUpdater;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import org.tasks.data.TaskContainer;
-import org.tasks.data.TaskListMetadata;
-import org.tasks.tasklist.ViewHolder;
-import timber.log.Timber;
-
-public final class AstridTaskAdapter extends TaskAdapter {
-
-  private final TaskListMetadata list;
-  private final Filter filter;
-  private final SubtasksFilterUpdater updater;
-  private final TaskDao taskDao;
-  private final Map<String, ArrayList<String>> chainedCompletions =
-      Collections.synchronizedMap(new HashMap<>());
-
-  AstridTaskAdapter(
-      TaskListMetadata list, Filter filter, SubtasksFilterUpdater updater, TaskDao taskDao) {
-    this.list = list;
-    this.filter = filter;
-    this.updater = updater;
-    this.taskDao = taskDao;
-  }
-
-  @Override
-  public int getIndent(TaskContainer task) {
-    return updater.getIndentForTask(task.getUuid());
-  }
-
-  @Override
-  public boolean canMove(ViewHolder source, ViewHolder target) {
-    return !updater.isDescendantOf(target.task.getUuid(), source.task.getUuid());
-  }
-
-  @Override
-  public int maxIndent(int previousPosition, TaskContainer task) {
-    TaskContainer previous = getTask(previousPosition);
-    String parentUuid = previous.getUuid();
-    return updater.getIndentForTask(parentUuid) + 1;
-  }
-
-  @Override
-  public boolean supportsParentingOrManualSort() {
-    return true;
-  }
-
-  @Override
-  public boolean supportsManualSorting() {
-    return true;
-  }
-
-  @Override
-  public void moved(int from, int to, int indent) {
-    TaskContainer source = getTask(from);
-    String targetTaskId = source.getUuid();
-
-    try {
-      if (to >= getCount()) {
-        updater.moveTo(list, filter, targetTaskId, "-1"); // $NON-NLS-1$
-      } else {
-        String destinationTaskId = getItemUuid(to);
-        updater.moveTo(list, filter, targetTaskId, destinationTaskId);
-      }
-      int currentIndent = updater.getIndentForTask(targetTaskId);
-      int delta = indent - currentIndent;
-      for (int i = 0 ; i < Math.abs(delta) ; i++) {
-        updater.indent(list, filter, targetTaskId, delta);
-      }
-    } catch (Exception e) {
-      Timber.e(e);
-    }
-  }
-
-  @Override
-  public void onTaskCreated(String uuid) {
-    updater.onCreateTask(list, filter, uuid);
-  }
-
-  @Override
-  public void onTaskDeleted(Task task) {
-    updater.onDeleteTask(list, filter, task.getUuid());
-  }
-
-  @Override
-  public void onCompletedTask(TaskContainer item, boolean completedState) {
-    final String itemId = item.getUuid();
-
-    final long completionDate = completedState ? DateUtilities.now() : 0;
-
-    if (!completedState) {
-      ArrayList<String> chained = chainedCompletions.get(itemId);
-      if (chained != null) {
-        for (String taskId : chained) {
-          taskDao.setCompletionDate(taskId, completionDate);
-        }
-      }
-      return;
-    }
-
-    final ArrayList<String> chained = new ArrayList<>();
-    updater.applyToDescendants(
-        itemId,
-        node -> {
-          String uuid = node.uuid;
-          taskDao.setCompletionDate(uuid, completionDate);
-          chained.add(node.uuid);
-        });
-
-    if (chained.size() > 0) {
-      // move recurring items to item parent
-      List<Task> tasks = taskDao.getRecurringTasks(chained);
-
-      boolean madeChanges = false;
-      for (Task t : tasks) {
-        if (!isNullOrEmpty(t.getRecurrence())) {
-          updater.moveToParentOf(t.getUuid(), itemId);
-          madeChanges = true;
-        }
-      }
-
-      if (madeChanges) {
-        updater.writeSerialization(list, updater.serializeTree());
-      }
-
-      chainedCompletions.put(itemId, chained);
-    }
-  }
-
-  @Override
-  public boolean supportsHiddenTasks() {
-    return false;
-  }
-}

app/src/main/java/com/todoroo/astrid/adapter/AstridTaskAdapter.kt

@@ -0,0 +1,97 @@
+package com.todoroo.astrid.adapter
+
+import com.todoroo.andlib.utility.DateUtilities
+import com.todoroo.astrid.api.Filter
+import com.todoroo.astrid.dao.TaskDao
+import com.todoroo.astrid.data.Task
+import com.todoroo.astrid.subtasks.SubtasksFilterUpdater
+import org.tasks.Strings.isNullOrEmpty
+import org.tasks.data.TaskContainer
+import org.tasks.data.TaskListMetadata
+import org.tasks.tasklist.ViewHolder
+import timber.log.Timber
+import java.util.*
+import kotlin.math.abs
+
+class AstridTaskAdapter internal constructor(
+        private val list: TaskListMetadata,
+        private val filter: Filter,
+        private val updater: SubtasksFilterUpdater,
+        private val taskDao: TaskDao) : TaskAdapter() {
+
+    private val chainedCompletions = Collections.synchronizedMap(HashMap<String, ArrayList<String>>())
+
+    override fun getIndent(task: TaskContainer) = updater.getIndentForTask(task.uuid)
+
+    override fun canMove(source: ViewHolder, target: ViewHolder) = !updater.isDescendantOf(target.task.uuid, source.task.uuid)
+
+    override fun maxIndent(previousPosition: Int, task: TaskContainer): Int {
+        val previous = getTask(previousPosition)
+        return updater.getIndentForTask(previous.uuid) + 1
+    }
+
+    override fun supportsParentingOrManualSort() = true
+
+    override fun supportsManualSorting() = true
+
+    override fun moved(from: Int, to: Int, indent: Int) {
+        val source = getTask(from)
+        val targetTaskId = source.uuid
+        try {
+            if (to >= count) {
+                updater.moveTo(list, filter, targetTaskId, "-1") // $NON-NLS-1$
+            } else {
+                val destinationTaskId = getItemUuid(to)
+                updater.moveTo(list, filter, targetTaskId, destinationTaskId)
+            }
+            val currentIndent = updater.getIndentForTask(targetTaskId)
+            val delta = indent - currentIndent
+            for (i in 0 until abs(delta)) {
+                updater.indent(list, filter, targetTaskId, delta)
+            }
+        } catch (e: Exception) {
+            Timber.e(e)
+        }
+    }
+
+    override fun onTaskCreated(uuid: String) = updater.onCreateTask(list, filter, uuid)
+
+    override fun onTaskDeleted(task: Task) = updater.onDeleteTask(list, filter, task.uuid)
+
+    override fun onCompletedTask(task: TaskContainer, newState: Boolean) {
+        val itemId = task.uuid
+        val completionDate = if (newState) DateUtilities.now() else 0
+        if (!newState) {
+            val chained = chainedCompletions[itemId]
+            if (chained != null) {
+                for (taskId in chained) {
+                    taskDao.setCompletionDate(taskId, completionDate)
+                }
+            }
+            return
+        }
+        val chained = ArrayList<String>()
+        updater.applyToDescendants(itemId) { node: SubtasksFilterUpdater.Node ->
+            val uuid = node.uuid
+            taskDao.setCompletionDate(uuid, completionDate)
+            chained.add(node.uuid)
+        }
+        if (chained.size > 0) {
+            // move recurring items to item parent
+            val tasks = taskDao.getRecurringTasks(chained)
+            var madeChanges = false
+            for (t in tasks) {
+                if (!isNullOrEmpty(t.recurrence)) {
+                    updater.moveToParentOf(t.uuid, itemId)
+                    madeChanges = true
+                }
+            }
+            if (madeChanges) {
+                updater.writeSerialization(list, updater.serializeTree())
+            }
+            chainedCompletions[itemId] = chained
+        }
+    }
+
+    override fun supportsHiddenTasks() = false
+}

app/src/main/java/com/todoroo/astrid/adapter/CaldavTaskAdapter.java

@@ -1,110 +0,0 @@
-package com.todoroo.astrid.adapter;
-
-import com.todoroo.astrid.dao.TaskDao;
-import org.tasks.data.CaldavDao;
-import org.tasks.data.CaldavTask;
-import org.tasks.data.SubsetCaldav;
-import org.tasks.data.TaskContainer;
-import org.tasks.tasklist.ViewHolder;
-
-public final class CaldavTaskAdapter extends TaskAdapter {
-
-  private final TaskDao taskDao;
-  private final CaldavDao caldavDao;
-
-  CaldavTaskAdapter(TaskDao taskDao, CaldavDao caldavDao) {
-    this.taskDao = taskDao;
-    this.caldavDao = caldavDao;
-  }
-
-  @Override
-  public boolean canMove(ViewHolder sourceVh, ViewHolder targetVh) {
-    TaskContainer source = sourceVh.task;
-    int to = targetVh.getAdapterPosition();
-    return !taskIsChild(source, to);
-  }
-
-  @Override
-  public int maxIndent(int previousPosition, TaskContainer task) {
-    TaskContainer previous = getTask(previousPosition);
-    return previous.getIndent() + 1;
-  }
-
-  @Override
-  public int minIndent(int nextPosition, TaskContainer task) {
-    return 0;
-  }
-
-  @Override
-  public boolean supportsParentingOrManualSort() {
-    return true;
-  }
-
-  @Override
-  public void moved(int from, int to, int indent) {
-    TaskContainer task = getTask(from);
-    TaskContainer previous = to > 0 ? getTask(to - 1) : null;
-
-    long newParent = task.getParent();
-    if (indent == 0) {
-      newParent = 0;
-    } else if (previous != null) {
-      if (indent == previous.getIndent()) {
-        newParent = previous.getParent();
-      } else if (indent > previous.getIndent()) {
-        newParent = previous.getId();
-      } else if (indent < previous.getIndent()) {
-        newParent = previous.getParent();
-        int currentIndex = to;
-        for (int i = 0 ; i < previous.getIndent() - indent ; i++) {
-          long thisParent = newParent;
-          while (newParent == thisParent) {
-            thisParent = getTask(--currentIndex).getParent();
-          }
-          newParent = thisParent;
-        }
-      }
-    }
-
-    // If nothing is changing, return
-    if (newParent == task.getParent()) {
-      return;
-    }
-
-    changeParent(task, newParent);
-
-    taskDao.touch(task.getId());
-  }
-
-  private void changeParent(TaskContainer task, long newParent) {
-    SubsetCaldav caldavTask = task.getCaldavTask();
-
-    if (newParent == 0) {
-      caldavTask.setRemoteParent("");
-      task.setParent(0);
-    } else {
-      CaldavTask parentTask = caldavDao.getTask(newParent);
-      if (parentTask == null) {
-        return;
-      }
-      caldavTask.setRemoteParent(parentTask.getRemoteId());
-      task.setParent(newParent);
-    }
-    caldavDao.update(caldavTask);
-    taskDao.save(task.getTask());
-  }
-
-  private boolean taskIsChild(TaskContainer source, int destinationIndex) {
-    TaskContainer destination = getTask(destinationIndex);
-    while (destination.getParent() != 0) {
-      if (destination.getParent() == source.getParent()) {
-        return false;
-      }
-      if (destination.getParent() == source.getId()) {
-        return true;
-      }
-      destination = getTask(--destinationIndex);
-    }
-    return false;
-  }
-}

app/src/main/java/com/todoroo/astrid/adapter/CaldavTaskAdapter.kt

@@ -0,0 +1,80 @@
+package com.todoroo.astrid.adapter
+
+import com.todoroo.astrid.dao.TaskDao
+import org.tasks.data.CaldavDao
+import org.tasks.data.TaskContainer
+import org.tasks.tasklist.ViewHolder
+
+class CaldavTaskAdapter internal constructor(private val taskDao: TaskDao, private val caldavDao: CaldavDao) : TaskAdapter() {
+    override fun canMove(sourceVh: ViewHolder, targetVh: ViewHolder): Boolean {
+        val source = sourceVh.task
+        val to = targetVh.adapterPosition
+        return !taskIsChild(source, to)
+    }
+
+    override fun maxIndent(previousPosition: Int, task: TaskContainer): Int {
+        val previous = getTask(previousPosition)
+        return previous.getIndent() + 1
+    }
+
+    override fun minIndent(nextPosition: Int, task: TaskContainer) = 0
+
+    override fun supportsParentingOrManualSort() = true
+
+    override fun moved(from: Int, to: Int, indent: Int) {
+        val task = getTask(from)
+        val previous = if (to > 0) getTask(to - 1) else null
+        var newParent = task.parent
+        if (indent == 0) {
+            newParent = 0
+        } else if (previous != null) {
+            when {
+                indent == previous.getIndent() -> newParent = previous.parent
+                indent > previous.getIndent() -> newParent = previous.id
+                indent < previous.getIndent() -> {
+                    newParent = previous.parent
+                    var currentIndex = to
+                    for (i in 0 until previous.getIndent() - indent) {
+                        var thisParent = newParent
+                        while (newParent == thisParent) {
+                            thisParent = getTask(--currentIndex).parent
+                        }
+                        newParent = thisParent
+                    }
+                }
+            }
+        }
+
+        // If nothing is changing, return
+        if (newParent == task.parent) {
+            return
+        }
+        changeParent(task, newParent)
+        taskDao.touch(task.id)
+    }
+
+    private fun changeParent(task: TaskContainer, newParent: Long) {
+        val caldavTask = task.getCaldavTask()
+        if (newParent == 0L) {
+            caldavTask.remoteParent = ""
+            task.parent = 0
+        } else {
+            val parentTask = caldavDao.getTask(newParent) ?: return
+            caldavTask.remoteParent = parentTask.remoteId
+            task.parent = newParent
+        }
+        caldavDao.update(caldavTask)
+        taskDao.save(task.getTask())
+    }
+
+    private fun taskIsChild(source: TaskContainer, destinationIndex: Int): Boolean {
+        (destinationIndex downTo 0).forEach {
+            when (getTask(it).parent) {
+                0L -> return false
+                source.parent -> return false
+                source.id -> return true
+            }
+        }
+        return false
+    }
+}

app/src/main/java/com/todoroo/astrid/adapter/GoogleTaskAdapter.java

@@ -1,51 +0,0 @@
-package com.todoroo.astrid.adapter;
-
-import com.todoroo.astrid.dao.TaskDao;
-import org.tasks.BuildConfig;
-import org.tasks.data.GoogleTaskDao;
-import org.tasks.data.SubsetGoogleTask;
-import org.tasks.data.TaskContainer;
-
-public final class GoogleTaskAdapter extends GoogleTaskManualSortAdapter {
-
-  private final boolean newTasksOnTop;
-
-  GoogleTaskAdapter(TaskDao taskDao, GoogleTaskDao googleTaskDao, boolean newTasksOnTop) {
-    super(taskDao, googleTaskDao);
-    this.newTasksOnTop = newTasksOnTop;
-  }
-
-  @Override
-  public boolean supportsManualSorting() {
-    return false;
-  }
-
-  @Override
-  public void moved(int from, int to, int indent) {
-    TaskContainer task = getTask(from);
-    SubsetGoogleTask googleTask = task.getGoogleTask();
-    TaskContainer previous = to > 0 ? getTask(to - 1) : null;
-    if (indent == 0) {
-      if (googleTask.getIndent() == 0) {
-        return;
-      }
-      googleTaskDao.move(
-          googleTask, 0, newTasksOnTop ? 0 : googleTaskDao.getBottom(googleTask.getListId(), 0));
-    } else {
-      long newParent = previous.hasParent() ? previous.getParent() : previous.getId();
-      if (googleTask.getParent() == newParent) {
-        return;
-      }
-      googleTaskDao.move(
-          googleTask,
-          newParent,
-          newTasksOnTop ? 0 : googleTaskDao.getBottom(googleTask.getListId(), newParent));
-    }
-
-    taskDao.touch(task.getId());
-
-    if (BuildConfig.DEBUG) {
-      googleTaskDao.validateSorting(task.getGoogleTaskList());
-    }
-  }
-}

app/src/main/java/com/todoroo/astrid/adapter/GoogleTaskAdapter.kt

@@ -0,0 +1,35 @@
+package com.todoroo.astrid.adapter
+
+import com.todoroo.astrid.dao.TaskDao
+import org.tasks.BuildConfig
+import org.tasks.data.GoogleTaskDao
+
+class GoogleTaskAdapter internal constructor(taskDao: TaskDao, googleTaskDao: GoogleTaskDao, private val newTasksOnTop: Boolean) : GoogleTaskManualSortAdapter(taskDao, googleTaskDao) {
+    override fun supportsManualSorting() = false
+
+    override fun moved(from: Int, to: Int, indent: Int) {
+        val task = getTask(from)
+        val googleTask = task.googleTask
+        val previous = if (to > 0) getTask(to - 1) else null
+        if (indent == 0) {
+            if (googleTask.indent == 0) {
+                return
+            }
+            googleTaskDao.move(
+                    googleTask, 0, if (newTasksOnTop) 0 else googleTaskDao.getBottom(googleTask.listId, 0))
+        } else {
+            val newParent = if (previous!!.hasParent()) previous.parent else previous.id
+            if (googleTask.parent == newParent) {
+                return
+            }
+            googleTaskDao.move(
+                    googleTask,
+                    newParent,
+                    if (newTasksOnTop) 0 else googleTaskDao.getBottom(googleTask.listId, newParent))
+        }
+        taskDao.touch(task.id)
+        if (BuildConfig.DEBUG) {
+            googleTaskDao.validateSorting(task.googleTaskList)
+        }
+    }
+}

app/src/main/java/com/todoroo/astrid/adapter/GoogleTaskManualSortAdapter.java

@@ -1,109 +0,0 @@
-package com.todoroo.astrid.adapter;
-
-import com.todoroo.astrid.dao.TaskDao;
-import org.tasks.BuildConfig;
-import org.tasks.data.GoogleTaskDao;
-import org.tasks.data.SubsetGoogleTask;
-import org.tasks.data.TaskContainer;
-import org.tasks.tasklist.ViewHolder;
-
-public class GoogleTaskManualSortAdapter extends TaskAdapter {
-
-  final TaskDao taskDao;
-  final GoogleTaskDao googleTaskDao;
-
-  GoogleTaskManualSortAdapter(TaskDao taskDao, GoogleTaskDao googleTaskDao) {
-    this.taskDao = taskDao;
-    this.googleTaskDao = googleTaskDao;
-  }
-
-  @Override
-  public boolean canMove(ViewHolder sourceVh, ViewHolder targetVh) {
-    TaskContainer source = sourceVh.task;
-    int to = targetVh.getAdapterPosition();
-
-    if (!source.hasChildren() || to <= 0 || to >= getCount() - 1) {
-      return true;
-    }
-
-    TaskContainer target = targetVh.task;
-    if (sourceVh.getAdapterPosition() < to) {
-      if (target.hasChildren()) {
-        return false;
-      }
-      if (target.hasParent()) {
-        return target.isLastSubtask();
-      }
-      return true;
-    } else {
-      if (target.hasChildren()) {
-        return true;
-      }
-      if (target.hasParent()) {
-        return target.getParent() == source.getId() && target.secondarySort == 0;
-      }
-      return true;
-    }
-  }
-
-  @Override
-  public int maxIndent(int previousPosition, TaskContainer task) {
-    return task.hasChildren() ? 0 : 1;
-  }
-
-  @Override
-  public int minIndent(int nextPosition, TaskContainer task) {
-    return task.hasChildren() || !getTask(nextPosition).hasParent() ? 0 : 1;
-  }
-
-  @Override
-  public boolean supportsParentingOrManualSort() {
-    return true;
-  }
-
-  @Override
-  public boolean supportsManualSorting() {
-    return true;
-  }
-
-  @Override
-  public void moved(int from, int to, int indent) {
-    TaskContainer task = getTask(from);
-    SubsetGoogleTask googleTask = task.getGoogleTask();
-    TaskContainer previous = to > 0 ? getTask(to - 1) : null;
-
-    if (previous == null) {
-      googleTaskDao.move(googleTask, 0, 0);
-    } else if (to == getCount() || to <= from) {
-      if (indent == 0) {
-        googleTaskDao.move(googleTask, 0, previous.getPrimarySort() + 1);
-      } else if (previous.hasParent()) {
-        googleTaskDao.move(googleTask, previous.getParent(), previous.getSecondarySort() + 1);
-      } else {
-        googleTaskDao.move(googleTask, previous.getId(), 0);
-      }
-    } else {
-      if (indent == 0) {
-        googleTaskDao.move(
-            googleTask,
-            0,
-            task.hasParent() ? previous.getPrimarySort() + 1 : previous.getPrimarySort());
-      } else if (previous.hasParent()) {
-        googleTaskDao.move(
-            googleTask,
-            previous.getParent(),
-            task.getParent() == previous.getParent()
-                ? previous.getSecondarySort()
-                : previous.getSecondarySort() + 1);
-      } else {
-        googleTaskDao.move(googleTask, previous.getId(), 0);
-      }
-    }
-
-    taskDao.touch(task.getId());
-
-    if (BuildConfig.DEBUG) {
-      googleTaskDao.validateSorting(task.getGoogleTaskList());
-    }
-  }
-}

app/src/main/java/com/todoroo/astrid/adapter/GoogleTaskManualSortAdapter.kt

@@ -0,0 +1,75 @@
+package com.todoroo.astrid.adapter
+
+import com.todoroo.astrid.dao.TaskDao
+import org.tasks.BuildConfig
+import org.tasks.data.GoogleTaskDao
+import org.tasks.data.TaskContainer
+import org.tasks.tasklist.ViewHolder
+
+open class GoogleTaskManualSortAdapter internal constructor(val taskDao: TaskDao, val googleTaskDao: GoogleTaskDao) : TaskAdapter() {
+
+    override fun canMove(sourceVh: ViewHolder, targetVh: ViewHolder): Boolean {
+        val source = sourceVh.task
+        val to = targetVh.adapterPosition
+        if (!source.hasChildren() || to <= 0 || to >= count - 1) {
+            return true
+        }
+        val target = targetVh.task
+        return if (sourceVh.adapterPosition < to) {
+            if (target.hasChildren()) {
+                return false
+            }
+            if (target.hasParent()) {
+                target.isLastSubtask
+            } else true
+        } else {
+            if (target.hasChildren()) {
+                return true
+            }
+            if (target.hasParent()) {
+                target.parent == source.id && target.secondarySort == 0L
+            } else true
+        }
+    }
+
+    override fun maxIndent(previousPosition: Int, task: TaskContainer) = if (task.hasChildren()) 0 else 1
+
+    override fun minIndent(nextPosition: Int, task: TaskContainer) = if (task.hasChildren() || !getTask(nextPosition).hasParent()) 0 else 1
+
+    override fun supportsParentingOrManualSort() = true
+
+    override fun supportsManualSorting() = true
+
+    override fun moved(from: Int, to: Int, indent: Int) {
+        val task = getTask(from)
+        val googleTask = task.googleTask
+        val previous = if (to > 0) getTask(to - 1) else null
+        if (previous == null) {
+            googleTaskDao.move(googleTask, 0, 0)
+        } else if (to == count || to <= from) {
+            when {
+                indent == 0 -> googleTaskDao.move(googleTask, 0, previous.getPrimarySort() + 1)
+                previous.hasParent() -> googleTaskDao.move(googleTask, previous.parent, previous.getSecondarySort() + 1)
+                else -> googleTaskDao.move(googleTask, previous.id, 0)
+            }
+        } else {
+            when {
+                indent == 0 ->
+                    googleTaskDao.move(
+                            googleTask,
+                            0,
+                            if (task.hasParent()) previous.getPrimarySort() + 1 else previous.getPrimarySort())
+                previous.hasParent() ->
+                    googleTaskDao.move(
+                            googleTask,
+                            previous.parent,
+                            if (task.parent == previous.parent) previous.getSecondarySort() else previous.getSecondarySort() + 1)
+                else -> googleTaskDao.move(googleTask, previous.id, 0)
+            }
+        }
+        taskDao.touch(task.id)
+        if (BuildConfig.DEBUG) {
+            googleTaskDao.validateSorting(task.googleTaskList)
+        }
+    }
+}

app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.java

@@ -1,115 +0,0 @@
-/*
- * Copyright (c) 2012 Todoroo Inc
- *
- * See the file "LICENSE" for the full license governing this code.
- */
-
-package com.todoroo.astrid.adapter;
-
-import static com.google.common.primitives.Longs.asList;
-
-import com.todoroo.astrid.data.Task;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
-import org.tasks.data.TaskContainer;
-import org.tasks.tasklist.TaskListRecyclerAdapter;
-import org.tasks.tasklist.ViewHolder;
-
-/**
- * Adapter for displaying a user's tasks as a list
- *
- * @author Tim Su <tim@todoroo.com>
- */
-public class TaskAdapter {
-
-  private final Set<Long> selected = new HashSet<>();
-  private TaskListRecyclerAdapter helper;
-
-  int getCount() {
-    return helper.getItemCount();
-  }
-
-  public void setHelper(TaskListRecyclerAdapter helper) {
-    this.helper = helper;
-  }
-
-  public int getNumSelected() {
-    return selected.size();
-  }
-
-  public ArrayList<Long> getSelected() {
-    return new ArrayList<>(selected);
-  }
-
-  public void setSelected(long... ids) {
-    setSelected(asList(ids));
-  }
-
-  public void setSelected(Collection<Long> ids) {
-    selected.clear();
-    selected.addAll(ids);
-  }
-
-  public void clearSelections() {
-    selected.clear();
-  }
-
-  public int getIndent(TaskContainer task) {
-    return task.getIndent();
-  }
-
-  public boolean canMove(ViewHolder source, ViewHolder target) {
-    return false;
-  }
-
-  public int maxIndent(int previousPosition, TaskContainer task) {
-    return 0;
-  }
-
-  public int minIndent(int nextPosition, TaskContainer task) {
-    return 0;
-  }
-
-  public boolean isSelected(TaskContainer task) {
-    return selected.contains(task.getId());
-  }
-
-  public void toggleSelection(TaskContainer task) {
-    long id = task.getId();
-    if (selected.contains(id)) {
-      selected.remove(id);
-    } else {
-      selected.add(id);
-    }
-  }
-
-  public boolean supportsParentingOrManualSort() {
-    return false;
-  }
-
-  public boolean supportsManualSorting() {
-    return false;
-  }
-
-  public void moved(int from, int to, int indent) {}
-
-  TaskContainer getTask(int position) {
-    return helper.getItem(position);
-  }
-
-  String getItemUuid(int position) {
-    return getTask(position).getUuid();
-  }
-
-  public void onCompletedTask(TaskContainer task, boolean newState) {}
-
-  public void onTaskCreated(String uuid) {}
-
-  public void onTaskDeleted(Task task) {}
-
-  public boolean supportsHiddenTasks() {
-    return true;
-  }
-}

app/src/main/java/com/todoroo/astrid/adapter/TaskAdapter.kt

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2012 Todoroo Inc
+ *
+ * See the file "LICENSE" for the full license governing this code.
+ */
+package com.todoroo.astrid.adapter
+
+import com.todoroo.astrid.data.Task
+import org.tasks.data.TaskContainer
+import org.tasks.tasklist.TaskListRecyclerAdapter
+import org.tasks.tasklist.ViewHolder
+import java.util.*
+
+open class TaskAdapter {
+    private val selected = HashSet<Long>()
+    private lateinit var helper: TaskListRecyclerAdapter
+
+    val count: Int
+        get() = helper.itemCount
+
+    fun setHelper(helper: TaskListRecyclerAdapter) {
+        this.helper = helper
+    }
+
+    val numSelected: Int
+        get() = selected.size
+
+    fun getSelected(): ArrayList<Long> = ArrayList(selected)
+
+    fun setSelected(vararg ids: Long) = setSelected(ids.toList())
+
+    fun setSelected(ids: Collection<Long>) {
+        selected.clear()
+        selected.addAll(ids)
+    }
+
+    fun clearSelections() = selected.clear()
+
+    open fun getIndent(task: TaskContainer): Int = task.getIndent()
+
+    open fun canMove(source: ViewHolder, target: ViewHolder): Boolean = false
+
+    open fun maxIndent(previousPosition: Int, task: TaskContainer): Int = 0
+
+    open fun minIndent(nextPosition: Int, task: TaskContainer): Int = 0
+
+    fun isSelected(task: TaskContainer): Boolean = selected.contains(task.id)
+
+    fun toggleSelection(task: TaskContainer) {
+        val id = task.id
+        if (selected.contains(id)) {
+            selected.remove(id)
+        } else {
+            selected.add(id)
+        }
+    }
+
+    open fun supportsParentingOrManualSort(): Boolean = false
+
+    open fun supportsManualSorting(): Boolean = false
+
+    open fun moved(from: Int, to: Int, indent: Int) {}
+
+    fun getTask(position: Int): TaskContainer = helper.getItem(position)
+
+    fun getItemUuid(position: Int): String = getTask(position).uuid
+
+    open fun onCompletedTask(task: TaskContainer, newState: Boolean) {}
+
+    open fun onTaskCreated(uuid: String) {}
+
+    open fun onTaskDeleted(task: Task) {}
+
+    open fun supportsHiddenTasks(): Boolean = true
+}