1 /* 2 * Copyright (C) 2015 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 package android.databinding; 17 18 import java.util.List; 19 20 /** 21 * A {@link List} that notifies when changes are made. An ObservableList bound to the UI 22 * will keep the it up-to-date when changes occur. 23 * <p> 24 * The ObservableList must notify its callbacks whenever a change to the list occurs, using 25 * {@link OnListChangedCallback}. 26 * <p> 27 * ObservableArrayList implements ObservableList with an underlying ArrayList. 28 * ListChangeRegistry can help in maintaining the callbacks of other implementations. 29 * 30 * @see Observable 31 * @see ObservableMap 32 */ 33 public interface ObservableList<T> extends List<T> { 34 35 /** 36 * Adds a callback to be notified when changes to the list occur. 37 * @param callback The callback to be notified on list changes 38 */ 39 void addOnListChangedCallback(OnListChangedCallback<? extends ObservableList<T>> callback); 40 41 /** 42 * Removes a callback previously added. 43 * @param callback The callback to remove. 44 */ 45 void removeOnListChangedCallback(OnListChangedCallback<? extends ObservableList<T>> callback); 46 47 /** 48 * The callback that is called by ObservableList when the list has changed. 49 */ 50 abstract class OnListChangedCallback<T extends ObservableList> { 51 52 /** 53 * Called whenever a change of unknown type has occurred, such as the entire list being 54 * set to new values. 55 * 56 * @param sender The changing list. 57 */ 58 public abstract void onChanged(T sender); 59 60 /** 61 * Called whenever one or more items in the list have changed. 62 * @param sender The changing list. 63 * @param positionStart The starting index that has changed. 64 * @param itemCount The number of items that have changed. 65 */ 66 public abstract void onItemRangeChanged(T sender, int positionStart, int itemCount); 67 68 /** 69 * Called whenever items have been inserted into the list. 70 * @param sender The changing list. 71 * @param positionStart The insertion index 72 * @param itemCount The number of items that have been inserted 73 */ 74 public abstract void onItemRangeInserted(T sender, int positionStart, int itemCount); 75 76 /** 77 * Called whenever items in the list have been moved. 78 * @param sender The changing list. 79 * @param fromPosition The position from which the items were moved 80 * @param toPosition The destination position of the items 81 * @param itemCount The number of items moved 82 */ 83 public abstract void onItemRangeMoved(T sender, int fromPosition, int toPosition, 84 int itemCount); 85 86 /** 87 * Called whenever items in the list have been deleted. 88 * @param sender The changing list. 89 * @param positionStart The starting index of the deleted items. 90 * @param itemCount The number of items removed. 91 */ 92 public abstract void onItemRangeRemoved(T sender, int positionStart, int itemCount); 93 } 94 } 95
