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  */
14 package android.support.v17.leanback.widget;
15 
16 /**
17  * Interface for receiving notification when a row or item becomes selected.
18  */
19 public interface OnItemViewSelectedListener {
20     /**
21      * Called when the a row or a new item becomes selected.  The concept of current selection
22      * is different than focus.  Row or item can be selected even they don't have focus.
23      * Having the concept of selection will allow developer to switch background to selected
24      * item or selected row when user selects rows outside row UI (e.g. headers left of
25      * rows).
26      * <p>
27      * For a none {@link ListRow} case,  parameter item is always null.  Event is fired when
28      * selection changes between rows, regardless if row view has focus or not.
29      * <p>
30      * For a {@link ListRow} case, parameter item can be null if the list row is empty.
31      * </p>
32      * <p>
33      * In the case of a grid, the row parameter is always null.
34      * </p>
35      * <li>
36      * Row has focus: event is fired when focus changes between child of the row.
37      * </li>
38      * <li>
39      * None of the row has focus: the event is fired with the current selected row and last
40      * focused item in the row.
41      * </li>
42      *
43      * @param itemViewHolder The view holder of item that is currently selected.
44      * @param item The item that is currently selected.
45      * @param rowViewHolder The view holder of row that is currently selected.
46      * @param row The row that is currently selected.
47      */
onItemSelected(Presenter.ViewHolder itemViewHolder, Object item, RowPresenter.ViewHolder rowViewHolder, Row row)48     public void onItemSelected(Presenter.ViewHolder itemViewHolder, Object item,
49             RowPresenter.ViewHolder rowViewHolder, Row row);
50 }
51