1 /* 2 * Copyright (C) 2008 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.launcher2; 18 19 import android.graphics.Rect; 20 21 /** 22 * Interface defining an object that can receive a drag. 23 * 24 */ 25 public interface DropTarget { 26 27 class DragObject { 28 public int x = -1; 29 public int y = -1; 30 31 /** X offset from the upper-left corner of the cell to where we touched. */ 32 public int xOffset = -1; 33 34 /** Y offset from the upper-left corner of the cell to where we touched. */ 35 public int yOffset = -1; 36 37 /** This indicates whether a drag is in final stages, either drop or cancel. It 38 * differentiates onDragExit, since this is called when the drag is ending, above 39 * the current drag target, or when the drag moves off the current drag object. 40 */ 41 public boolean dragComplete = false; 42 43 /** The view that moves around while you drag. */ 44 public DragView dragView = null; 45 46 /** The data associated with the object being dragged */ 47 public Object dragInfo = null; 48 49 /** Where the drag originated */ 50 public DragSource dragSource = null; 51 52 /** Post drag animation runnable */ 53 public Runnable postAnimationRunnable = null; 54 55 /** Indicates that the drag operation was cancelled */ 56 public boolean cancelled = false; 57 58 public DragObject() { 59 } 60 } 61 62 /** 63 * Used to temporarily disable certain drop targets 64 * 65 * @return boolean specifying whether this drop target is currently enabled 66 */ 67 boolean isDropEnabled(); 68 69 /** 70 * Handle an object being dropped on the DropTarget 71 * 72 * @param source DragSource where the drag started 73 * @param x X coordinate of the drop location 74 * @param y Y coordinate of the drop location 75 * @param xOffset Horizontal offset with the object being dragged where the original 76 * touch happened 77 * @param yOffset Vertical offset with the object being dragged where the original 78 * touch happened 79 * @param dragView The DragView that's being dragged around on screen. 80 * @param dragInfo Data associated with the object being dragged 81 * 82 */ 83 void onDrop(DragObject dragObject); 84 85 void onDragEnter(DragObject dragObject); 86 87 void onDragOver(DragObject dragObject); 88 89 void onDragExit(DragObject dragObject); 90 91 /** 92 * Allows a DropTarget to delegate drag and drop events to another object. 93 * 94 * Most subclasses will should just return null from this method. 95 * 96 * @param source DragSource where the drag started 97 * @param x X coordinate of the drop location 98 * @param y Y coordinate of the drop location 99 * @param xOffset Horizontal offset with the object being dragged where the original 100 * touch happened 101 * @param yOffset Vertical offset with the object being dragged where the original 102 * touch happened 103 * @param dragView The DragView that's being dragged around on screen. 104 * @param dragInfo Data associated with the object being dragged 105 * 106 * @return The DropTarget to delegate to, or null to not delegate to another object. 107 */ 108 DropTarget getDropTargetDelegate(DragObject dragObject); 109 110 /** 111 * Check if a drop action can occur at, or near, the requested location. 112 * This will be called just before onDrop. 113 * 114 * @param source DragSource where the drag started 115 * @param x X coordinate of the drop location 116 * @param y Y coordinate of the drop location 117 * @param xOffset Horizontal offset with the object being dragged where the 118 * original touch happened 119 * @param yOffset Vertical offset with the object being dragged where the 120 * original touch happened 121 * @param dragView The DragView that's being dragged around on screen. 122 * @param dragInfo Data associated with the object being dragged 123 * @return True if the drop will be accepted, false otherwise. 124 */ 125 boolean acceptDrop(DragObject dragObject); 126 127 // These methods are implemented in Views 128 void getHitRect(Rect outRect); 129 void getLocationInDragLayer(int[] loc); 130 int getLeft(); 131 int getTop(); 132 } 133
