content: /*
   * Copyright (C) 2008 The Android Open Source Project
   *
   * Licensed 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 com.android.launcher3;
  
  import android.graphics.Rect;
  
  import com.android.launcher3.accessibility.DragViewStateAnnouncer;
  import com.android.launcher3.dragndrop.DragView;
  
  /**
   * Interface defining an object that can receive a drag.
   *
   */
  public interface DropTarget {
  
      class DragObject {
          public int x = -1;
          public int y = -1;
  
          /** X offset from the upper-left corner of the cell to where we touched.  */
          public int xOffset = -1;
  
          /** Y offset from the upper-left corner of the cell to where we touched.  */
          public int yOffset = -1;
  
          /** This indicates whether a drag is in final stages, either drop or cancel. It
           * differentiates onDragExit, since this is called when the drag is ending, above
           * the current drag target, or when the drag moves off the current drag object.
           */
          public boolean dragComplete = false;
  
          /** The view that moves around while you drag.  */
          public DragView dragView = null;
  
          /** The data associated with the object, after item is dropped. */
          public ItemInfo dragInfo = null;
  
          /** The data associated with the object  being dragged */
          public ItemInfo originalDragInfo = null;
  
          /** Where the drag originated */
          public DragSource dragSource = null;
  
          /** The object is part of an accessible drag operation */
          public boolean accessibleDrag;
  
          /** Post drag animation runnable */
          public Runnable postAnimationRunnable = null;
  
          /** Indicates that the drag operation was cancelled */
          public boolean cancelled = false;
  
          /** Defers removing the DragView from the DragLayer until after the drop animation. */
          public boolean deferDragViewCleanupPostAnimation = true;
  
          public DragViewStateAnnouncer stateAnnouncer;
  
          public DragObject() {
          }
  
          /**
           * This is used to compute the visual center of the dragView. This point is then
           * used to visualize drop locations and determine where to drop an item. The idea is that
           * the visual center represents the user's interpretation of where the item is, and hence
           * is the appropriate point to use when determining drop location.
           */
          public final float[] getVisualCenter(float[] recycle) {
              final float res[] = (recycle == null) ? new float[2] : recycle;
  
              // These represent the visual top and left of drag view if a dragRect was provided.
              // If a dragRect was not provided, then they correspond to the actual view left and
              // top, as the dragRect is in that case taken to be the entire dragView.
              // R.dimen.dragViewOffsetY.
              int left = x - xOffset;
              int top = y - yOffset;
  
              // In order to find the visual center, we shift by half the dragRect
              res[0] = left + dragView.getDragRegion().width() / 2;
              res[1] = top + dragView.getDragRegion().height() / 2;
  
              return res;
          }
      }
  
      /**
       * Used to temporarily disable certain drop targets
       *
       * @return boolean specifying whether this drop target is currently enabled
       */
      boolean isDropEnabled();
  
      /**
       * Handle an object being dropped on the DropTarget
       */
      void onDrop(DragObject dragObject);
  
      void onDragEnter(DragObject dragObject);
  
      void onDragOver(DragObject dragObject);
  
      void onDragExit(DragObject dragObject);
  
      /**
       * Check if a drop action can occur at, or near, the requested location.
       * This will be called just before onDrop.
       * @return True if the drop will be accepted, false otherwise.
       */
      boolean acceptDrop(DragObject dragObject);
  
      void prepareAccessibilityDrop();
  
      // These methods are implemented in Views
      void getHitRectRelativeToDragLayer(Rect outRect);
  }
  