ViewCache.java revision 944779887775bd950cf1abf348d2df461593f6ab 
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 */
16package com.android.tv.util;
17
18import android.content.Context;
19import android.util.SparseArray;
20import android.view.LayoutInflater;
21import android.view.View;
22import android.view.ViewGroup;
23import java.util.ArrayList;
24
25/** A cache for the views. */
26public 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