Make habit deletions instantaneous

Fixes #133

app/src/main/java/org/isoron/uhabits/ui/habits/list/ListHabitsSelectionMenu.java

@@ -79,22 +79,22 @@ public class ListHabitsSelectionMenu extends BaseSelectionMenu
         switch (item.getItemId())
         {
             case R.id.action_edit_habit:
-                edit(firstHabit);
+                showEditScreen(firstHabit);
                 finish();
                 return true;
 
             case R.id.action_archive_habit:
-                archive(selected);
+                performArchive(selected);
                 finish();
                 return true;
 
             case R.id.action_unarchive_habit:
-                unarchive(selected);
+                performUnarchive(selected);
                 finish();
                 return true;
 
             case R.id.action_delete:
-                delete(selected);
+                performDelete(selected);
                 return true;
 
             case R.id.action_color:
@@ -164,24 +164,26 @@ public class ListHabitsSelectionMenu extends BaseSelectionMenu
         return R.menu.list_habits_selection;
     }
 
-    private void archive(@NonNull List<Habit> selected)
+    private void performArchive(@NonNull List<Habit> selected)
     {
         commandRunner.execute(new ArchiveHabitsCommand(habitList, selected),
             null);
     }
 
-    private void delete(@NonNull List<Habit> selected)
+    private void performDelete(@NonNull List<Habit> selected)
     {
         screen.showDeleteConfirmationScreen(() -> {
+            listAdapter.performRemove(selected);
             commandRunner.execute(new DeleteHabitsCommand(habitList, selected),
                 null);
             finish();
         });
     }
 
-    private void edit(@NonNull Habit firstHabit)
+    private void performUnarchive(@NonNull List<Habit> selected)
     {
-        screen.showEditHabitScreen(firstHabit);
+        commandRunner.execute(new UnarchiveHabitsCommand(habitList, selected),
+            null);
     }
 
     private void showColorPicker(@NonNull List<Habit> selected,
@@ -194,9 +196,8 @@ public class ListHabitsSelectionMenu extends BaseSelectionMenu
         });
     }
 
-    private void unarchive(@NonNull List<Habit> selected)
+    private void showEditScreen(@NonNull Habit firstHabit)
     {
-        commandRunner.execute(new UnarchiveHabitsCommand(habitList, selected),
-            null);
+        screen.showEditHabitScreen(firstHabit);
     }
 }

app/src/main/java/org/isoron/uhabits/ui/habits/list/controllers/HabitCardListController.java

@@ -83,7 +83,7 @@ public class HabitCardListController implements HabitCardListView.Controller
 
         Habit habitFrom = adapter.getItem(from);
         Habit habitTo = adapter.getItem(to);
-        adapter.reorder(from, to);
+        adapter.performReorder(from, to);
 
         if (habitListener != null)
             habitListener.onHabitReorder(habitFrom, habitTo);

app/src/main/java/org/isoron/uhabits/ui/habits/list/model/HabitCardListAdapter.java

@@ -199,9 +199,21 @@ public class HabitCardListAdapter
         observable.notifyListeners();
     }
 
-    public void refresh()
+    /**
+     * Removes a list of habits from the adapter.
+     * <p>
+     * Note that this only has effect on the adapter cache. The database is not
+     * modified, and the change is lost when the cache is refreshed. This method
+     * is useful for making the ListView more responsive: while we wait for the
+     * database operation to finish, the cache can be modified to reflect the
+     * changes immediately.
+     *
+     * @param habits list of habits to be removed
+     */
+    public void performRemove(List<Habit> habits)
     {
-        cache.refreshAllHabits();
+        for (Habit h : habits)
+            cache.remove(h.getId());
     }
 
     /**
@@ -216,10 +228,14 @@ public class HabitCardListAdapter
      * @param from the habit that should be moved
      * @param to   the habit that currently occupies the desired position
      */
-    public void reorder(int from, int to)
+    public void performReorder(int from, int to)
     {
         cache.reorder(from, to);
-        notifyItemMoved(from, to);
+    }
+
+    public void refresh()
+    {
+        cache.refreshAllHabits();
     }
 
     public void setFilter(HabitMatcher matcher)

app/src/main/java/org/isoron/uhabits/ui/habits/list/model/HabitCardListCache.java

@@ -165,6 +165,20 @@ public class HabitCardListCache implements CommandRunner.Listener
         this.progressBar = progressBar;
     }
 
+    public void remove(@NonNull Long id)
+    {
+        Habit h = data.id_to_habit.get(id);
+        if(h == null) return;
+
+        int position = data.habits.indexOf(h);
+        data.habits.remove(position);
+        data.id_to_habit.remove(id);
+        data.checkmarks.remove(id);
+        data.scores.remove(id);
+
+        if (listener != null) listener.onItemRemoved(position);
+    }
+
     /**
      * Interface definition for a callback to be invoked when the data on the
      * cache has been modified.
@@ -298,6 +312,8 @@ public class HabitCardListCache implements CommandRunner.Listener
         protected void onPreExecute()
         {
             super.onPreExecute();
+            progressBar.setTotal(0);
+
             new Handler().postDelayed(() -> {
                 if (getStatus() == Status.RUNNING) progressBar.show();
             }, 1000);
@@ -367,16 +383,7 @@ public class HabitCardListCache implements CommandRunner.Listener
             Set<Long> removed = new TreeSet<>(before);
             removed.removeAll(after);
 
-            for (Long id : removed)
-            {
-                Habit h = data.id_to_habit.get(id);
-                int position = data.habits.indexOf(h);
-                data.habits.remove(position);
-                data.id_to_habit.remove(id);
-                data.checkmarks.remove(id);
-                data.scores.remove(id);
-                if (listener != null) listener.onItemRemoved(position);
-            }
+            for (Long id : removed) remove(id);
         }
     }
 }

app/src/test/java/org/isoron/uhabits/ui/habits/list/controllers/HabitCardListControllerTest.java

@@ -119,7 +119,7 @@ public class HabitCardListControllerTest extends BaseUnitTest
         controller.drop(1, 3);
         verify(habitListener).onHabitReorder(habits.get(1), habits.get(3));
         verify(selectionListener).onSelectionFinish();
-        verify(adapter).reorder(1, 3);
+        verify(adapter).performReorder(1, 3);
         resetMocks();
     }
 
@@ -134,7 +134,7 @@ public class HabitCardListControllerTest extends BaseUnitTest
         controller.drop(0, 3);
         verify(habitListener).onHabitReorder(habits.get(0), habits.get(3));
         verify(selectionListener).onSelectionFinish();
-        verify(adapter).reorder(0, 3);
+        verify(adapter).performReorder(0, 3);
         verify(adapter).clearSelection();
     }