Google Tasks' style drag and drop

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

@@ -43,7 +43,6 @@ public final class AstridTaskAdapter extends TaskAdapter {
     return true;
   }
 
-  @Override
   public boolean canIndent(int position, TaskContainer task) {
     String parentUuid = getItemUuid(position - 1);
     int parentIndent = updater.getIndentForTask(parentUuid);
@@ -56,7 +55,7 @@ public final class AstridTaskAdapter extends TaskAdapter {
   }
 
   @Override
-  public void moved(int from, int to) {
+  public void moved(int from, int to, int indent) {
     String targetTaskId = getItemUuid(from);
     if (!Task.isValidUuid(targetTaskId)) {
       return; // This can happen with gestures on empty parts of the list (e.g. extra space below
@@ -76,7 +75,7 @@ public final class AstridTaskAdapter extends TaskAdapter {
   }
 
   @Override
-  public void indented(int which, int delta) {
+  public void swiped(int which, int delta) {
     String targetTaskId = getItemUuid(which);
     if (!Task.isValidUuid(targetTaskId)) {
       return; // This can happen with gestures on empty parts of the list (e.g. extra space below

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

@@ -23,7 +23,7 @@ public final class GoogleTaskAdapter extends TaskAdapter {
 
   @Override
   public int getIndent(TaskContainer task) {
-    return task.getParent() > 0 ? 1 : 0;
+    return task.getIndent();
   }
 
   @Override
@@ -56,8 +56,13 @@ public final class GoogleTaskAdapter extends TaskAdapter {
   }
 
   @Override
-  public boolean canIndent(int position, TaskContainer task) {
-    return position > 0 && !task.hasChildren() && !task.hasParent();
+  public int maxIndent(int position, TaskContainer task) {
+    return position == 0 || task.hasChildren() ? 0 : 1;
+  }
+
+  @Override
+  public int minIndent(int nextPosition, TaskContainer task) {
+    return task.hasChildren() || !getTask(nextPosition).hasParent() ? 0 : 1;
   }
 
   @Override
@@ -66,51 +71,36 @@ public final class GoogleTaskAdapter extends TaskAdapter {
   }
 
   @Override
-  public void moved(int from, int to) {
+  public void moved(int from, int to, int indent) {
     TaskContainer task = getTask(from);
     GoogleTask googleTask = task.getGoogleTask();
-    if (to == 0) {
+    TaskContainer previous = to > 0 ? getTask(to - 1) : null;
+
+    if (previous == null) {
       googleTaskDao.move(googleTask, 0, 0);
-    } else if (to == getCount()) {
-      TaskContainer previous = getTask(to - 1);
-      if (googleTask.getParent() > 0 && googleTask.getParent() == previous.getParent()) {
-        googleTaskDao.move(googleTask, googleTask.getParent(), previous.getSecondarySort());
-      } else {
-        googleTaskDao.move(googleTask, 0, previous.getPrimarySort());
-      }
-    } else if (from < to) {
-      TaskContainer previous = getTask(to - 1);
-      TaskContainer next = getTask(to);
-      if (previous.hasParent()) {
-        if (next.hasParent()) {
-          googleTaskDao.move(googleTask, next.getParent(), next.getSecondarySort());
-        } else if (task.getParent() == previous.getParent() || next.hasParent()) {
-          googleTaskDao.move(googleTask, previous.getParent(), previous.getSecondarySort());
+    } 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, 0, previous.getPrimarySort());
-        }
-      } else if (previous.hasChildren()) {
         googleTaskDao.move(googleTask, previous.getId(), 0);
-      } else if (task.hasParent()) {
-        googleTaskDao.move(googleTask, 0, next.getPrimarySort());
-      } else {
-        googleTaskDao.move(googleTask, 0, previous.getPrimarySort());
       }
     } else {
-      TaskContainer previous = getTask(to - 1);
-      TaskContainer next = getTask(to);
-      if (previous.hasParent()) {
-        if (next.hasParent()) {
-          googleTaskDao.move(googleTask, next.getParent(), next.getSecondarySort());
-        } else if (task.getParent() == previous.getParent()) {
-          googleTaskDao.move(googleTask, previous.getParent(), previous.getSecondarySort());
+      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, 0, previous.getPrimarySort() + 1);
-        }
-      } else if (previous.hasChildren()) {
         googleTaskDao.move(googleTask, previous.getId(), 0);
-      } else {
-        googleTaskDao.move(googleTask, 0, previous.getPrimarySort() + 1);
       }
     }
 
@@ -125,24 +115,6 @@ public final class GoogleTaskAdapter extends TaskAdapter {
   }
 
   @Override
-  public void indented(int which, int delta) {
-    TaskContainer task = getTask(which);
-    TaskContainer previous;
-    GoogleTask current = task.getGoogleTask();
-    if (delta == -1) {
-      googleTaskDao.unindent(googleTaskDao.getByTaskId(task.getParent()), current);
-    } else {
-      previous = getTask(which - 1);
-      googleTaskDao.indent(googleTaskDao.getByTaskId(previous.getId()), current);
-    }
-
-    Task update = task.getTask();
-    update.setModificationDate(now());
-    update.putTransitory(SyncFlags.FORCE_SYNC, true);
-    taskDao.save(update);
-
-    if (BuildConfig.DEBUG) {
-      googleTaskDao.validateSorting(task.getGoogleTaskList());
-    }
+  public void swiped(int which, int delta) {
   }
 }

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

@@ -60,8 +60,12 @@ public class TaskAdapter {
     return false;
   }
 
-  public boolean canIndent(int position, TaskContainer task) {
-    return false;
+  public int maxIndent(int position, TaskContainer task) {
+    return 0;
+  }
+
+  public int minIndent(int nextPosition, TaskContainer task) {
+    return 0;
   }
 
   public boolean isSelected(TaskContainer task) {
@@ -81,9 +85,9 @@ public class TaskAdapter {
     return false;
   }
 
-  public void moved(int from, int to) {}
+  public void moved(int from, int to, int indent) {}
 
-  public void indented(int position, int delta) {}
+  public void swiped(int position, int delta) {}
 
   public TaskContainer getTask(int position) {
     return helper.getItem(position);

app/src/main/java/org/tasks/data/GoogleTaskDao.java

@@ -43,32 +43,6 @@ public abstract class GoogleTaskDao {
       "UPDATE google_tasks SET gt_order = gt_order - 1 WHERE gt_list_id = :listId AND gt_parent = :parent AND gt_order >= :position")
   abstract void shiftUp(String listId, long parent, long position);
 
-  @Transaction
-  public void unindent(GoogleTask parent, GoogleTask task) {
-    String list = parent.getListId();
-    shiftUp(list, task.getParent(), task.getOrder());
-    long newPosition = parent.getOrder() + 1;
-    shiftDown(list, 0, newPosition);
-    task.setParent(0);
-    task.setOrder(newPosition);
-    task.setMoved(true);
-    update(task);
-  }
-
-  @Transaction
-  public void indent(GoogleTask previous, GoogleTask task) {
-    shiftUp(previous.getListId(), 0, task.getOrder());
-    if (previous.getParent() == 0) {
-      task.setParent(previous.getTask());
-      task.setOrder(0);
-    } else {
-      task.setParent(previous.getParent());
-      task.setOrder(previous.getOrder() + 1);
-    }
-    task.setMoved(true);
-    update(task);
-  }
-
   @Transaction
   public void move(GoogleTask task, long newParent, long newPosition) {
     long previousParent = task.getParent();

app/src/main/java/org/tasks/data/TaskContainer.java

@@ -13,6 +13,7 @@ public class TaskContainer {
   public long primarySort;
   public long secondarySort;
   @Deprecated public int indent;
+  private int targetIndent;
 
   public String getTagsString() {
     return tags;
@@ -83,11 +84,15 @@ public class TaskContainer {
   }
 
   public int getIndent() {
+    if (googletask != null) {
+      return getParent() > 0 ? 1 : 0;
+    }
     return indent;
   }
 
   public void setIndent(int indent) {
     this.indent = indent;
+    targetIndent = indent;
   }
 
   @Override
@@ -113,6 +118,12 @@ public class TaskContainer {
     if (secondarySort != that.secondarySort) {
       return false;
     }
+    if (indent != that.indent) {
+      return false;
+    }
+    if (targetIndent != that.targetIndent) {
+      return false;
+    }
     if (task != null ? !task.equals(that.task) : that.task != null) {
       return false;
     }
@@ -135,6 +146,8 @@ public class TaskContainer {
     result = 31 * result + siblings;
     result = 31 * result + (int) (primarySort ^ (primarySort >>> 32));
     result = 31 * result + (int) (secondarySort ^ (secondarySort >>> 32));
+    result = 31 * result + indent;
+    result = 31 * result + targetIndent;
     return result;
   }
 
@@ -161,6 +174,8 @@ public class TaskContainer {
         + secondarySort
         + ", indent="
         + indent
+        + ", targetIndent="
+        + targetIndent
         + '}';
   }
 
@@ -191,4 +206,12 @@ public class TaskContainer {
   public GoogleTask getGoogleTask() {
     return googletask;
   }
+
+  public void setTargetIndent(int indent) {
+    targetIndent = indent;
+  }
+
+  public int getTargetIndent() {
+    return targetIndent;
+  }
 }

app/src/main/java/org/tasks/tasklist/ItemTouchHelperCallback.java

@@ -1,6 +1,8 @@
 package org.tasks.tasklist;
 
 import static androidx.recyclerview.widget.ItemTouchHelper.DOWN;
+import static androidx.recyclerview.widget.ItemTouchHelper.LEFT;
+import static androidx.recyclerview.widget.ItemTouchHelper.RIGHT;
 import static androidx.recyclerview.widget.ItemTouchHelper.UP;
 
 import android.graphics.Canvas;
@@ -10,6 +12,7 @@ import androidx.recyclerview.widget.RecyclerView;
 import com.todoroo.astrid.activity.TaskListFragment;
 import com.todoroo.astrid.adapter.TaskAdapter;
 import com.todoroo.astrid.utility.Flags;
+import org.tasks.data.TaskContainer;
 
 public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
   private final TaskAdapter adapter;
@@ -19,6 +22,7 @@ public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
   private int from = -1;
   private int to = -1;
   private boolean dragging;
+  private boolean swiping;
 
   ItemTouchHelperCallback(
       TaskAdapter adapter,
@@ -38,51 +42,50 @@ public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
       recyclerAdapter.startActionMode();
       ((ViewHolder) viewHolder).setMoving(true);
       dragging = true;
+      int position = viewHolder.getAdapterPosition();
+      updateIndents((ViewHolder) viewHolder, position, position);
+    } else if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
+      ((ViewHolder) viewHolder).setSwiping(true);
+      swiping = true;
     }
   }
 
   @Override
   public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
     return adapter.isManuallySorted() && adapter.getNumSelected() == 0
-        ? makeMovementFlags(UP | DOWN, getSwipeFlags((ViewHolder) viewHolder))
+        ? makeMovementFlags(UP | DOWN | LEFT | RIGHT, 0)
         : makeMovementFlags(0, 0);
   }
 
-  private int getSwipeFlags(ViewHolder vh) {
-    int indentFlags = 0;
-    if (vh.isIndented()) {
-      indentFlags |= ItemTouchHelper.LEFT;
-    }
-    int position = vh.getAdapterPosition();
-    if (position > 0 && adapter.canIndent(position, vh.task)) {
-      indentFlags |= ItemTouchHelper.RIGHT;
-    }
-    return indentFlags;
-  }
-
   @Override
   public boolean onMove(
       @NonNull RecyclerView recyclerView,
-      @NonNull RecyclerView.ViewHolder source,
+      @NonNull RecyclerView.ViewHolder src,
       @NonNull RecyclerView.ViewHolder target) {
     recyclerAdapter.finishActionMode();
-    int fromPosition = source.getAdapterPosition();
+    int fromPosition = src.getAdapterPosition();
     int toPosition = target.getAdapterPosition();
-    if (!adapter.canMove((ViewHolder) source, (ViewHolder) target)) {
+    ViewHolder source = (ViewHolder) src;
+    if (!adapter.canMove(source, (ViewHolder) target)) {
       return false;
     }
     if (from == -1) {
-      ((ViewHolder) source).setSelected(false);
+      source.setSelected(false);
       from = fromPosition;
     }
     to = toPosition;
     recyclerAdapter.notifyItemMoved(fromPosition, toPosition);
+    updateIndents(source, from, to);
     return true;
   }
 
-  @Override
-  public float getSwipeThreshold(RecyclerView.ViewHolder viewHolder) {
-    return .2f;
+  private void updateIndents(ViewHolder source, int from, int to) {
+    TaskContainer task = source.task;
+    source.setMinIndent(
+        to == 0 || to == recyclerAdapter.getItemCount() - 1
+            ? 0
+            : adapter.minIndent(from <= to ? to + 1 : to, task));
+    source.setMaxIndent(adapter.maxIndent(to, task));
   }
 
   @Override
@@ -94,9 +97,39 @@ public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
       float dY,
       int actionState,
       boolean isCurrentlyActive) {
-    if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
-      float shiftSize = ((ViewHolder) viewHolder).getShiftSize();
-      dX = Math.max(-shiftSize, Math.min(shiftSize, dX));
+    ViewHolder vh = (ViewHolder) viewHolder;
+    TaskContainer task = vh.task;
+    float shiftSize = vh.getShiftSize();
+    if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
+      int currentIndent = ((ViewHolder) viewHolder).getIndent();
+      int maxIndent = vh.getMaxIndent();
+      int minIndent = vh.getMinIndent();
+      if (isCurrentlyActive) {
+        float dxAdjusted;
+        if (dX > 0) {
+          dxAdjusted = Math.min(dX, (maxIndent - currentIndent) * shiftSize);
+        } else {
+          dxAdjusted = Math.max((currentIndent - minIndent) * -shiftSize, dX);
+        }
+
+        int targetIndent = currentIndent + Float.valueOf(dxAdjusted / shiftSize).intValue();
+
+        if (targetIndent != task.getIndent()) {
+          if (from == -1) {
+            recyclerAdapter.finishActionMode();
+            vh.setSelected(false);
+          }
+        }
+        if (targetIndent < minIndent) {
+          task.setTargetIndent(minIndent);
+        } else if (targetIndent > maxIndent) {
+          task.setTargetIndent(maxIndent);
+        } else {
+          task.setTargetIndent(targetIndent);
+        }
+      }
+
+      dX = (task.getTargetIndent() - task.getIndent()) * shiftSize;
     }
     super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
   }
@@ -106,17 +139,27 @@ public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
     super.clearView(recyclerView, viewHolder);
     ViewHolder vh = (ViewHolder) viewHolder;
     vh.setMoving(false);
-    onClear.run();
+    vh.setSwiping(false);
     dragging = false;
+    swiping = false;
+    onClear.run();
     if (recyclerAdapter.isActionModeActive()) {
       recyclerAdapter.toggle(vh);
     } else {
+      TaskContainer task = vh.task;
+      int targetIndent = task.getTargetIndent();
       if (from >= 0 && from != to) {
         if (from < to) {
           to++;
         }
-        recyclerAdapter.moved(from, to);
-        taskList.loadTaskListContent();
+        vh.task.setIndent(targetIndent);
+        vh.setIndent(targetIndent);
+        recyclerAdapter.moved(from, to, targetIndent);
+      } else if (task.getIndent() != targetIndent) {
+        int position = vh.getAdapterPosition();
+        vh.task.setIndent(targetIndent);
+        vh.setIndent(targetIndent);
+        recyclerAdapter.moved(position, position, targetIndent);
       }
     }
     from = -1;
@@ -126,11 +169,20 @@ public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {
 
   @Override
   public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
-    adapter.indented(viewHolder.getAdapterPosition(), direction == ItemTouchHelper.RIGHT ? 1 : -1);
+    ViewHolder vh = (ViewHolder) viewHolder;
+    vh.setSwiping(false);
+    swiping = false;
+    int delta = direction == ItemTouchHelper.RIGHT ? 1 : -1;
+    int position = viewHolder.getAdapterPosition();
+    recyclerAdapter.swiped(position, delta);
     taskList.loadTaskListContent();
   }
 
-  public boolean isDragging() {
+  boolean isDragging() {
     return dragging;
   }
+
+  boolean isSwiping() {
+    return swiping;
+  }
 }

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

@@ -99,7 +99,7 @@ public class TaskListRecyclerAdapter extends RecyclerView.Adapter<ViewHolder>
 
     updates.add(update);
 
-    if (!itemTouchHelperCallback.isDragging()) {
+    if (!itemTouchHelperCallback.isDragging() && !itemTouchHelperCallback.isSwiping()) {
       drainQueue();
     }
   }
@@ -258,9 +258,13 @@ public class TaskListRecyclerAdapter extends RecyclerView.Adapter<ViewHolder>
     notifyItemRangeChanged(position, count, payload);
   }
 
-  void moved(int from, int to) {
-    adapter.moved(from, to);
+  void moved(int from, int to, int indent) {
+    adapter.moved(from, to, indent);
     TaskContainer task = list.remove(from);
     list.add(from < to ? to - 1 : to, task);
   }
+
+  void swiped(int position, int delta) {
+    adapter.swiped(position, delta);
+  }
 }

app/src/main/java/org/tasks/tasklist/ViewHolder.java

@@ -83,6 +83,9 @@ public class ViewHolder extends RecyclerView.ViewHolder {
   private boolean selected;
   private boolean moving;
   private boolean isGoogleTaskList;
+  private boolean swiping;
+  private int minIndent;
+  private int maxIndent;
 
   ViewHolder(
       Activity context,
@@ -200,10 +203,6 @@ public class ViewHolder extends RecyclerView.ViewHolder {
     return Math.round(indent * getShiftSize());
   }
 
-  boolean isIndented() {
-    return indent > 0;
-  }
-
   void bindView(TaskContainer task, boolean isGoogleTaskList) {
     this.task = task;
     this.isGoogleTaskList = isGoogleTaskList;
@@ -328,6 +327,40 @@ public class ViewHolder extends RecyclerView.ViewHolder {
     setTaskAppearance();
   }
 
+  public int getIndent() {
+    return indent;
+  }
+
+  void setSwiping(boolean swiping) {
+    this.swiping = swiping;
+  }
+
+  boolean isSwiping() {
+    return swiping;
+  }
+
+  void setMinIndent(int minIndent) {
+    this.minIndent = minIndent;
+    if (task.getTargetIndent() < minIndent) {
+      task.setTargetIndent(minIndent);
+    }
+  }
+
+  void setMaxIndent(int maxIndent) {
+    this.maxIndent = maxIndent;
+    if (task.getTargetIndent() > maxIndent) {
+      task.setTargetIndent(maxIndent);
+    }
+  }
+
+  int getMinIndent() {
+    return minIndent;
+  }
+
+  int getMaxIndent() {
+    return maxIndent;
+  }
+
   interface ViewHolderCallbacks {
 
     void onCompletedTask(TaskContainer task, boolean newState);