content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.weex.ui.component.list;
  
  import android.support.annotation.NonNull;
  import android.support.v7.widget.GridLayoutManager;
  import android.support.v7.widget.RecyclerView;
  import android.support.v7.widget.StaggeredGridLayoutManager;
  import android.support.v7.widget.helper.ItemTouchHelper;
  
  import org.apache.weex.ui.view.listview.adapter.ListBaseViewHolder;
  import org.apache.weex.utils.WXLogUtils;
  
  /**
   * Description:
   * An implementation of {@link ItemTouchHelper.Callback}. with drag&drop support:)
   *
   */
  class DragSupportCallback extends ItemTouchHelper.Callback {
      private final DragHelper mDragHelper;
      private boolean mEnableDifferentViewTypeDrag = false;
  
      private int dragFrom = -1;
      private int dragTo = -1;
  
      private static final String TAG = "WXListExComponent";
  
      DragSupportCallback(@NonNull DragHelper DragHelper) {
          this.mDragHelper = DragHelper;
          this.mEnableDifferentViewTypeDrag = false;
      }
  
      DragSupportCallback(@NonNull DragHelper DragHelper, boolean enableDifferentViewTypeDrag) {
          this.mDragHelper = DragHelper;
          this.mEnableDifferentViewTypeDrag = enableDifferentViewTypeDrag;
      }
  
      @Override
      public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
          if (recyclerView.getLayoutManager() instanceof GridLayoutManager || recyclerView.getLayoutManager() instanceof StaggeredGridLayoutManager) {
              int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
              int swipeFlags = 0;
              return makeMovementFlags(dragFlags, swipeFlags);
          } else {
              int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
              int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
              return makeMovementFlags(dragFlags, swipeFlags);
          }
      }
  
      @Override
      public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
          if (viewHolder == null || target == null) {
              return false;
          }
  
          if (!mEnableDifferentViewTypeDrag && viewHolder.getItemViewType() != target.getItemViewType()) {
              return false;
          }
  
          if (mDragHelper.isDragExcluded(viewHolder)) {
              return false;
          }
  
          try {
              int fromPos = viewHolder.getAdapterPosition();
              int toPos = target.getAdapterPosition();
  
              if (dragFrom == -1) {
                  dragFrom = fromPos;
              }
              dragTo = toPos;
  
              mDragHelper.onDragging(fromPos, toPos);
              return true;
          } catch (Exception e) {
              WXLogUtils.e(TAG, e.getMessage());
              return false;
          }
      }
  
  
      @Override
      public boolean isLongPressDragEnabled() {
          return mDragHelper.isDraggable() && mDragHelper.isLongPressDragEnabled();
      }
  
      @Override
      public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
      }
  
      @Override
      public boolean isItemViewSwipeEnabled() {
          return false;
      }
  
      @Override
      public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
          if (actionState != ItemTouchHelper.ACTION_STATE_IDLE && viewHolder instanceof ListBaseViewHolder) {
              ListBaseViewHolder vh = (ListBaseViewHolder) viewHolder;
              if (vh.getComponent() != null) {
                  mDragHelper.onDragStart(vh.getComponent(), vh.getAdapterPosition());
              }
          }
  
          super.onSelectedChanged(viewHolder, actionState);
      }
  
  
      @Override
      public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
          super.clearView(recyclerView, viewHolder);
  
          if (viewHolder instanceof ListBaseViewHolder) {
              ListBaseViewHolder vh = (ListBaseViewHolder) viewHolder;
              if (vh.getComponent() != null) {
                  if (dragFrom != -1 && dragTo != -1) {
                      mDragHelper.onDragEnd(vh.getComponent(), dragFrom, dragTo);
                  }
              }
  
          }
  
          dragFrom = dragTo = -1;
      }
  }
  