1 /* 2 * Copyright (C) 2019 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.launcher3.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 24 /** 25 * Utility class to cache views at an activity level 26 */ 27 public class ViewCache { 28 29 protected final SparseArray<CacheEntry> mCache = new SparseArray(); 30 setCacheSize(int layoutId, int size)31 public void setCacheSize(int layoutId, int size) { 32 mCache.put(layoutId, new CacheEntry(size)); 33 } 34 getView(int layoutId, Context context, ViewGroup parent)35 public <T extends View> T getView(int layoutId, Context context, ViewGroup parent) { 36 CacheEntry entry = mCache.get(layoutId); 37 if (entry == null) { 38 entry = new CacheEntry(1); 39 mCache.put(layoutId, entry); 40 } 41 42 if (entry.mCurrentSize > 0) { 43 entry.mCurrentSize --; 44 T result = (T) entry.mViews[entry.mCurrentSize]; 45 entry.mViews[entry.mCurrentSize] = null; 46 return result; 47 } 48 49 return (T) LayoutInflater.from(context).inflate(layoutId, parent, false); 50 } 51 recycleView(int layoutId, View view)52 public void recycleView(int layoutId, View view) { 53 CacheEntry entry = mCache.get(layoutId); 54 if (entry != null && entry.mCurrentSize < entry.mMaxSize) { 55 entry.mViews[entry.mCurrentSize] = view; 56 entry.mCurrentSize++; 57 } 58 } 59 60 private static class CacheEntry { 61 62 final int mMaxSize; 63 final View[] mViews; 64 65 int mCurrentSize; 66 CacheEntry(int maxSize)67 public CacheEntry(int maxSize) { 68 mMaxSize = maxSize; 69 mViews = new View[maxSize]; 70 mCurrentSize = 0; 71 } 72 } 73 } 74