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 17package android.support.v7.preference; 18 19import android.support.annotation.IdRes; 20import android.support.v7.widget.RecyclerView; 21import android.util.SparseArray; 22import android.view.View; 23 24/** 25 * A {@link android.support.v7.widget.RecyclerView.ViewHolder} class which caches views associated 26 * with the default {@link Preference} layouts. Cached views can be retrieved by calling 27 * {@link #findViewById(int)}. 28 */ 29public class PreferenceViewHolder extends RecyclerView.ViewHolder { 30 private final SparseArray<View> mCachedViews = new SparseArray<>(4); 31 private boolean mDividerAllowedAbove; 32 private boolean mDividerAllowedBelow; 33 34 /* package */ PreferenceViewHolder(View itemView) { 35 super(itemView); 36 37 // Pre-cache the views that we know in advance we'll want to find 38 mCachedViews.put(android.R.id.title, itemView.findViewById(android.R.id.title)); 39 mCachedViews.put(android.R.id.summary, itemView.findViewById(android.R.id.summary)); 40 mCachedViews.put(android.R.id.icon, itemView.findViewById(android.R.id.icon)); 41 mCachedViews.put(R.id.icon_frame, itemView.findViewById(R.id.icon_frame)); 42 mCachedViews.put(AndroidResources.ANDROID_R_ICON_FRAME, 43 itemView.findViewById(AndroidResources.ANDROID_R_ICON_FRAME)); 44 } 45 46 /** 47 * Returns a cached reference to a subview managed by this object. If the view reference is not 48 * yet cached, it falls back to calling {@link View#findViewById(int)} and caches the result. 49 * 50 * @param id Resource ID of the view to find 51 * @return The view, or null if no view with the requested ID is found. 52 */ 53 public View findViewById(@IdRes int id) { 54 final View cachedView = mCachedViews.get(id); 55 if (cachedView != null) { 56 return cachedView; 57 } else { 58 final View v = itemView.findViewById(id); 59 if (v != null) { 60 mCachedViews.put(id, v); 61 } 62 return v; 63 } 64 } 65 66 /** 67 * Dividers are only drawn between items if both items allow it, or above the first and below 68 * the last item if that item allows it. 69 * 70 * @return true if dividers are allowed above this item 71 */ 72 public boolean isDividerAllowedAbove() { 73 return mDividerAllowedAbove; 74 } 75 76 /** 77 * Dividers are only drawn between items if both items allow it, or above the first and below 78 * the last item if that item allows it. 79 * 80 * By default, {@link Preference#onBindViewHolder(PreferenceViewHolder)} will set this to the 81 * same value as returned by {@link Preference#isSelectable()}, so that non-selectable items 82 * do not have a divider drawn above them. 83 * 84 * @param allowed false to prevent dividers being drawn above this item 85 */ 86 public void setDividerAllowedAbove(boolean allowed) { 87 mDividerAllowedAbove = allowed; 88 } 89 90 /** 91 * Dividers are only drawn between items if both items allow it, or above the first and below 92 * the last item if that item allows it. 93 * 94 * @return true if dividers are allowed below this item 95 */ 96 public boolean isDividerAllowedBelow() { 97 return mDividerAllowedBelow; 98 } 99 100 /** 101 * Dividers are only drawn between items if both items allow it, or above the first and below 102 * the last item if that item allows it. 103 * 104 * By default, {@link Preference#onBindViewHolder(PreferenceViewHolder)} will set this to the 105 * same value as returned by {@link Preference#isSelectable()}, so that non-selectable items 106 * do not have a divider drawn below them. 107 * 108 * @param allowed false to prevent dividers being drawn below this item 109 */ 110 public void setDividerAllowedBelow(boolean allowed) { 111 mDividerAllowedBelow = allowed; 112 } 113} 114