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 android.support.v17.leanback.widget.ItemAlignmentFacet.ItemAlignmentDef;
17import android.support.v7.widget.RecyclerView;
18
19/**
20 * Interface for receiving notification when a child of this ViewGroup has been selected.
21 * There are two methods:
22 * <li>
23 *     {link {@link #onChildViewHolderSelected(RecyclerView, RecyclerView.ViewHolder, int, int)}}
24 *     is called when the view holder is about to be selected.  The listener could change size
25 *     of the view holder in this callback.
26 * </li>
27 * <li>
28 *     {link {@link #onChildViewHolderSelectedAndPositioned(RecyclerView, RecyclerView.ViewHolder,
29 *     int, int)} is called when view holder has been selected and laid out in RecyclerView.
30 *
31 * </li>
32 */
33public abstract class OnChildViewHolderSelectedListener {
34    /**
35     * Callback method to be invoked when a child of this ViewGroup has been selected. Listener
36     * might change the size of the child and the position of the child is not finalized. To get
37     * the final layout position of child, overide {@link #onChildViewHolderSelectedAndPositioned(
38     * RecyclerView, RecyclerView.ViewHolder, int, int)}.
39     *
40     * @param parent The RecyclerView where the selection happened.
41     * @param child The ViewHolder within the RecyclerView that is selected, or null if no
42     *        view is selected.
43     * @param position The position of the view in the adapter, or NO_POSITION
44     *        if no view is selected.
45     * @param subposition The index of which {@link ItemAlignmentDef} being used,
46     *                    0 if there is no ItemAlignmentDef defined for the item.
47     */
48    public void onChildViewHolderSelected(RecyclerView parent, RecyclerView.ViewHolder child,
49            int position, int subposition) {
50    }
51
52    /**
53     * Callback method to be invoked when a child of this ViewGroup has been selected and
54     * positioned.
55     *
56     * @param parent The RecyclerView where the selection happened.
57     * @param child The ViewHolder within the RecyclerView that is selected, or null if no
58     *        view is selected.
59     * @param position The position of the view in the adapter, or NO_POSITION
60     *        if no view is selected.
61     * @param subposition The index of which {@link ItemAlignmentDef} being used,
62     *                    0 if there is no ItemAlignmentDef defined for the item.
63     */
64    public void onChildViewHolderSelectedAndPositioned(RecyclerView parent,
65            RecyclerView.ViewHolder child, int position, int subposition) {
66    }
67
68}
69