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      1 /*
      2  * Copyright (C) 2017 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 package com.android.tv.util;
     17 
     18 import android.content.Context;
     19 import android.util.SparseArray;
     20 import android.view.LayoutInflater;
     21 import android.view.View;
     22 import android.view.ViewGroup;
     23 import java.util.ArrayList;
     24 
     25 /** A cache for the views. */
     26 public class ViewCache {
     27     private static final SparseArray<ArrayList<View>> mViews = new SparseArray();
     28 
     29     private static ViewCache sViewCache;
     30 
     31     private ViewCache() {}
     32 
     33     /** Returns an instance of the view cache. */
     34     public static ViewCache getInstance() {
     35         if (sViewCache == null) {
     36             sViewCache = new ViewCache();
     37         }
     38         return sViewCache;
     39     }
     40 
     41     /** Returns if the view cache is empty. */
     42     public boolean isEmpty() {
     43         return mViews.size() == 0;
     44     }
     45 
     46     /** Stores a view into this view cache. */
     47     public void putView(int resId, View view) {
     48         ArrayList<View> views = mViews.get(resId);
     49         if (views == null) {
     50             views = new ArrayList();
     51             mViews.put(resId, views);
     52         }
     53         views.add(view);
     54     }
     55 
     56     /** Stores multi specific views into the view cache. */
     57     public void putView(Context context, int resId, ViewGroup fakeParent, int num) {
     58         LayoutInflater inflater =
     59                 (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     60         ArrayList<View> views = mViews.get(resId);
     61         if (views == null) {
     62             views = new ArrayList<>();
     63             mViews.put(resId, views);
     64         }
     65         for (int i = 0; i < num; i++) {
     66             View view = inflater.inflate(resId, fakeParent, false);
     67             views.add(view);
     68         }
     69     }
     70 
     71     /** Returns the view for specific resource id. */
     72     public View getView(int resId) {
     73         ArrayList<View> views = mViews.get(resId);
     74         if (views != null && !views.isEmpty()) {
     75             View view = views.remove(views.size() - 1);
     76             if (views.isEmpty()) {
     77                 mViews.remove(resId);
     78             }
     79             return view;
     80         } else {
     81             return null;
     82         }
     83     }
     84 
     85     /** Returns the view if exists, or create a new view for the specific resource id. */
     86     public View getOrCreateView(LayoutInflater inflater, int resId, ViewGroup container) {
     87         View view = getView(resId);
     88         if (view == null) {
     89             view = inflater.inflate(resId, container, false);
     90         }
     91         return view;
     92     }
     93 
     94     /** Clears the view cache. */
     95     public void clear() {
     96         mViews.clear();
     97     }
     98 }
     99