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 androidx.leanback.widget; 15 16 import androidx.leanback.widget.ItemAlignmentFacet.ItemAlignmentDef; 17 import androidx.recyclerview.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 */ 33 public 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
