ArrayObjectAdapter.java revision a7ba44025ec38541f429a830763ff799b5e5267e 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14package android.support.v17.leanback.widget;
15
16import java.util.ArrayList;
17import java.util.Collection;
18
19/**
20 * Adapter implemented with an {@link ArrayList}.
21 */
22public class ArrayObjectAdapter extends ObjectAdapter {
23
24    private ArrayList<Object> mItems = new ArrayList<Object>();
25
26    public ArrayObjectAdapter(PresenterSelector presenterSelector) {
27        super(presenterSelector);
28    }
29
30    public ArrayObjectAdapter(Presenter presenter) {
31        super(presenter);
32    }
33
34    public ArrayObjectAdapter() {
35        super();
36    }
37
38    @Override
39    public int size() {
40        return mItems.size();
41    }
42
43    @Override
44    public Object get(int index) {
45        return mItems.get(index);
46    }
47
48    /**
49     * Search first occurrence of item in the list; return -1 if not found.
50     * @param item  The item to search in the list.
51     * @return First occurrence of item in the list or -1 if not found.
52     */
53    public int indexOf(Object item) {
54        return mItems.indexOf(item);
55    }
56
57    /**
58     * Notify content of range of items changed.  Note that this is not same
59     * as add or remove items.
60     * @param positionStart The position of first item that has changed.
61     * @param itemCount The count of how many items has changed.
62     */
63    public void notifyArrayItemRangeChanged(int positionStart, int itemCount) {
64        notifyItemRangeChanged(positionStart, itemCount);
65    }
66
67    /**
68     * Adds an item to the end of the list.
69     *
70     * @param item The item to add to the end of the list.
71     */
72    public void add(Object item) {
73        add(mItems.size(), item);
74    }
75
76    /**
77     * Inserts an item into this list at the specified index.
78     *
79     * @param index The index at which the item should be inserted.
80     * @param item The item to insert into the list.
81     */
82    public void add(int index, Object item) {
83        mItems.add(index, item);
84        notifyItemRangeInserted(index, 1);
85    }
86
87    /**
88     * Adds the objects in the given collection to the list, starting at the
89     * given index.
90     *
91     * @param index The index at which the items should be inserted.
92     * @param items A {@link Collection} of items to insert.
93     */
94    public void addAll(int index, Collection items) {
95        int itemsCount = items.size();
96        mItems.addAll(index, items);
97        notifyItemRangeInserted(index, itemsCount);
98    }
99
100    /**
101     * Removes the first occurrence of the given item from the list.
102     *
103     * @param item The item to remove from the list.
104     * @return True if the item was found and thus removed from the list.
105     */
106    public boolean remove(Object item) {
107        int index = mItems.indexOf(item);
108        if (index >= 0) {
109            mItems.remove(index);
110            notifyItemRangeRemoved(index, 1);
111        }
112        return index >= 0;
113    }
114
115    /**
116     * Removes a range of items from the list. The range is specified by giving
117     * the starting position and the number of elements to remove.
118     *
119     * @param position The index of the first item to remove.
120     * @param count The number of items to remove.
121     * @return The number of items removed.
122     */
123    public int removeItems(int position, int count) {
124        int itemsToRemove = Math.min(count, mItems.size() - position);
125
126        for (int i = 0; i < itemsToRemove; i++) {
127            mItems.remove(position);
128        }
129        notifyItemRangeRemoved(position, itemsToRemove);
130        return itemsToRemove;
131    }
132
133    /**
134     * Removes all items from this list, leaving it empty.
135     */
136    public void clear() {
137        int itemCount = mItems.size();
138        mItems.clear();
139        notifyItemRangeRemoved(0, itemCount);
140    }
141}
142