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 
ViewCache()31     private ViewCache() {}
32 
33     /** Returns an instance of the view cache. */
getInstance()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. */
isEmpty()42     public boolean isEmpty() {
43         return mViews.size() == 0;
44     }
45 
46     /** Stores a view into this view cache. */
putView(int resId, View view)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. */
putView(Context context, int resId, ViewGroup fakeParent, int num)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. */
getView(int resId)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. */
getOrCreateView(LayoutInflater inflater, int resId, ViewGroup container)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. */
clear()95     public void clear() {
96         mViews.clear();
97     }
98 }
99