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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.launcher3.dragndrop;
     18 
     19 import android.graphics.Point;
     20 
     21 import com.android.launcher3.DropTarget;
     22 
     23 /**
     24  * Set of options to control the drag and drop behavior.
     25  */
     26 public class DragOptions {
     27 
     28     /** Whether or not an accessible drag operation is in progress. */
     29     public boolean isAccessibleDrag = false;
     30 
     31     /** Specifies the start location for the system DnD, null when using internal DnD */
     32     public Point systemDndStartPoint = null;
     33 
     34     /** Determines when a pre-drag should transition to a drag. By default, this is immediate. */
     35     public PreDragCondition preDragCondition = null;
     36 
     37     /**
     38      * Specifies a condition that must be met before DragListener#onDragStart() is called.
     39      * By default, there is no condition and onDragStart() is called immediately following
     40      * DragController#startDrag().
     41      *
     42      * This condition can be overridden, and callbacks are provided for the following cases:
     43      * - The pre-drag starts, but onDragStart() is deferred (onPreDragStart()).
     44      * - The pre-drag ends before the condition is met (onPreDragEnd(false)).
     45      * - The actual drag starts when the condition is met (onPreDragEnd(true)).
     46      */
     47     public interface PreDragCondition {
     48 
     49         public boolean shouldStartDrag(double distanceDragged);
     50 
     51         /**
     52          * The pre-drag has started, but onDragStart() is
     53          * deferred until shouldStartDrag() returns true.
     54          */
     55         void onPreDragStart(DropTarget.DragObject dragObject);
     56 
     57         /**
     58          * The pre-drag has ended. This gets called at the same time as onDragStart()
     59          * if the condition is met, otherwise at the same time as onDragEnd().
     60          * @param dragStarted Whether the pre-drag ended because the actual drag started.
     61          *                    This will be true if the condition was met, otherwise false.
     62          */
     63         void onPreDragEnd(DropTarget.DragObject dragObject, boolean dragStarted);
     64     }
     65 }
     66