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      1 /*
      2  * Copyright 2018 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 
     17 package androidx.preference;
     18 
     19 import android.util.SparseArray;
     20 import android.view.View;
     21 
     22 import androidx.annotation.IdRes;
     23 import androidx.annotation.RestrictTo;
     24 import androidx.recyclerview.widget.RecyclerView;
     25 
     26 /**
     27  * A {@link RecyclerView.ViewHolder} class which caches views associated
     28  * with the default {@link Preference} layouts. Cached views can be retrieved by calling
     29  * {@link #findViewById(int)}.
     30  */
     31 public class PreferenceViewHolder extends RecyclerView.ViewHolder {
     32     private final SparseArray<View> mCachedViews = new SparseArray<>(4);
     33     private boolean mDividerAllowedAbove;
     34     private boolean mDividerAllowedBelow;
     35 
     36     /* package */ PreferenceViewHolder(View itemView) {
     37         super(itemView);
     38 
     39         // Pre-cache the views that we know in advance we'll want to find
     40         mCachedViews.put(android.R.id.title, itemView.findViewById(android.R.id.title));
     41         mCachedViews.put(android.R.id.summary, itemView.findViewById(android.R.id.summary));
     42         mCachedViews.put(android.R.id.icon, itemView.findViewById(android.R.id.icon));
     43         mCachedViews.put(R.id.icon_frame, itemView.findViewById(R.id.icon_frame));
     44         mCachedViews.put(AndroidResources.ANDROID_R_ICON_FRAME,
     45                 itemView.findViewById(AndroidResources.ANDROID_R_ICON_FRAME));
     46     }
     47 
     48     /** @hide */
     49     @RestrictTo(RestrictTo.Scope.TESTS)
     50     public static PreferenceViewHolder createInstanceForTests(View itemView) {
     51         return new PreferenceViewHolder(itemView);
     52     }
     53 
     54     /**
     55      * Returns a cached reference to a subview managed by this object. If the view reference is not
     56      * yet cached, it falls back to calling {@link View#findViewById(int)} and caches the result.
     57      *
     58      * @param id Resource ID of the view to find
     59      * @return The view, or null if no view with the requested ID is found.
     60      */
     61     public View findViewById(@IdRes int id) {
     62         final View cachedView = mCachedViews.get(id);
     63         if (cachedView != null) {
     64             return cachedView;
     65         } else {
     66             final View v = itemView.findViewById(id);
     67             if (v != null) {
     68                 mCachedViews.put(id, v);
     69             }
     70             return v;
     71         }
     72     }
     73 
     74     /**
     75      * Dividers are only drawn between items if both items allow it, or above the first and below
     76      * the last item if that item allows it.
     77      *
     78      * @return true if dividers are allowed above this item
     79      */
     80     public boolean isDividerAllowedAbove() {
     81         return mDividerAllowedAbove;
     82     }
     83 
     84     /**
     85      * Dividers are only drawn between items if both items allow it, or above the first and below
     86      * the last item if that item allows it.
     87      *
     88      * By default, {@link Preference#onBindViewHolder(PreferenceViewHolder)} will set this to the
     89      * same value as returned by {@link Preference#isSelectable()}, so that non-selectable items
     90      * do not have a divider drawn above them.
     91      *
     92      * @param allowed false to prevent dividers being drawn above this item
     93      */
     94     public void setDividerAllowedAbove(boolean allowed) {
     95         mDividerAllowedAbove = allowed;
     96     }
     97 
     98     /**
     99      * Dividers are only drawn between items if both items allow it, or above the first and below
    100      * the last item if that item allows it.
    101      *
    102      * @return true if dividers are allowed below this item
    103      */
    104     public boolean isDividerAllowedBelow() {
    105         return mDividerAllowedBelow;
    106     }
    107 
    108     /**
    109      * Dividers are only drawn between items if both items allow it, or above the first and below
    110      * the last item if that item allows it.
    111      *
    112      * By default, {@link Preference#onBindViewHolder(PreferenceViewHolder)} will set this to the
    113      * same value as returned by {@link Preference#isSelectable()}, so that non-selectable items
    114      * do not have a divider drawn below them.
    115      *
    116      * @param allowed false to prevent dividers being drawn below this item
    117      */
    118     public void setDividerAllowedBelow(boolean allowed) {
    119         mDividerAllowedBelow = allowed;
    120     }
    121 }
    122