1 /* 2 * Copyright (C) 2007 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 android.widget; 18 19 import android.database.DataSetObservable; 20 import android.database.DataSetObserver; 21 22 /** 23 * Base class for a {@link ExpandableListAdapter} used to provide data and Views 24 * from some data to an expandable list view. 25 * <p> 26 * Adapters inheriting this class should verify that the base implementations of 27 * {@link #getCombinedChildId(long, long)} and {@link #getCombinedGroupId(long)} 28 * are correct in generating unique IDs from the group/children IDs. 29 * <p> 30 * @see SimpleExpandableListAdapter 31 * @see SimpleCursorTreeAdapter 32 */ 33 public abstract class BaseExpandableListAdapter implements ExpandableListAdapter, 34 HeterogeneousExpandableList { 35 private final DataSetObservable mDataSetObservable = new DataSetObservable(); 36 registerDataSetObserver(DataSetObserver observer)37 public void registerDataSetObserver(DataSetObserver observer) { 38 mDataSetObservable.registerObserver(observer); 39 } 40 unregisterDataSetObserver(DataSetObserver observer)41 public void unregisterDataSetObserver(DataSetObserver observer) { 42 mDataSetObservable.unregisterObserver(observer); 43 } 44 45 /** 46 * @see DataSetObservable#notifyInvalidated() 47 */ notifyDataSetInvalidated()48 public void notifyDataSetInvalidated() { 49 mDataSetObservable.notifyInvalidated(); 50 } 51 52 /** 53 * @see DataSetObservable#notifyChanged() 54 */ notifyDataSetChanged()55 public void notifyDataSetChanged() { 56 mDataSetObservable.notifyChanged(); 57 } 58 areAllItemsEnabled()59 public boolean areAllItemsEnabled() { 60 return true; 61 } 62 onGroupCollapsed(int groupPosition)63 public void onGroupCollapsed(int groupPosition) { 64 } 65 onGroupExpanded(int groupPosition)66 public void onGroupExpanded(int groupPosition) { 67 } 68 69 /** 70 * Override this method if you foresee a clash in IDs based on this scheme: 71 * <p> 72 * Base implementation returns a long: 73 * <li> bit 0: Whether this ID points to a child (unset) or group (set), so for this method 74 * this bit will be 1. 75 * <li> bit 1-31: Lower 31 bits of the groupId 76 * <li> bit 32-63: Lower 32 bits of the childId. 77 * <p> 78 * {@inheritDoc} 79 */ getCombinedChildId(long groupId, long childId)80 public long getCombinedChildId(long groupId, long childId) { 81 return 0x8000000000000000L | ((groupId & 0x7FFFFFFF) << 32) | (childId & 0xFFFFFFFF); 82 } 83 84 /** 85 * Override this method if you foresee a clash in IDs based on this scheme: 86 * <p> 87 * Base implementation returns a long: 88 * <li> bit 0: Whether this ID points to a child (unset) or group (set), so for this method 89 * this bit will be 0. 90 * <li> bit 1-31: Lower 31 bits of the groupId 91 * <li> bit 32-63: Lower 32 bits of the childId. 92 * <p> 93 * {@inheritDoc} 94 */ getCombinedGroupId(long groupId)95 public long getCombinedGroupId(long groupId) { 96 return (groupId & 0x7FFFFFFF) << 32; 97 } 98 99 /** 100 * {@inheritDoc} 101 */ isEmpty()102 public boolean isEmpty() { 103 return getGroupCount() == 0; 104 } 105 106 107 /** 108 * {@inheritDoc} 109 * @return 0 for any group or child position, since only one child type count is declared. 110 */ getChildType(int groupPosition, int childPosition)111 public int getChildType(int groupPosition, int childPosition) { 112 return 0; 113 } 114 115 /** 116 * {@inheritDoc} 117 * @return 1 as a default value in BaseExpandableListAdapter. 118 */ getChildTypeCount()119 public int getChildTypeCount() { 120 return 1; 121 } 122 123 /** 124 * {@inheritDoc} 125 * @return 0 for any groupPosition, since only one group type count is declared. 126 */ getGroupType(int groupPosition)127 public int getGroupType(int groupPosition) { 128 return 0; 129 } 130 131 /** 132 * {@inheritDoc} 133 * @return 1 as a default value in BaseExpandableListAdapter. 134 */ getGroupTypeCount()135 public int getGroupTypeCount() { 136 return 1; 137 } 138 } 139