Java tutorial
/***************************************************************************** * BitmapCache.java ***************************************************************************** * Copyright 2012 VLC authors and VideoLAN * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ package com.yamin.kk.vlc; import android.app.ActivityManager; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.support.v4.util.LruCache; import android.util.Log; import android.view.View; public class BitmapCache { public final static String TAG = "VLC/BitmapCache"; private final static boolean LOG_ENABLED = false; private static BitmapCache mInstance; private final LruCache<String, Bitmap> mMemCache; public static BitmapCache getInstance() { if (mInstance == null) mInstance = new BitmapCache(); return mInstance; } private BitmapCache() { // Get the global context of the application Context context = VLCApplication.getAppContext(); // Get memory class of this device, exceeding this amount will throw an // OutOfMemory exception. final int memClass = ((ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE)) .getMemoryClass(); // Use 1/5th of the available memory for this memory cache. final int cacheSize = 1024 * 1024 * memClass / 5; Log.d(TAG, "LRUCache size sets to " + cacheSize); mMemCache = new LruCache<String, Bitmap>(cacheSize) { @Override protected int sizeOf(String key, Bitmap value) { return value.getRowBytes() * value.getHeight(); } }; } public Bitmap getBitmapFromMemCache(String key) { final Bitmap b = mMemCache.get(key); if (LOG_ENABLED) Log.d(TAG, (b == null) ? "Cache miss" : "Cache found"); if (b != null && b.isRecycled()) { /* A recycled bitmap cannot be used again */ mMemCache.remove(key); return null; } return b; } public void addBitmapToMemCache(String key, Bitmap bitmap) { if (key != null && bitmap != null && getBitmapFromMemCache(key) == null) mMemCache.put(key, bitmap); } private Bitmap getBitmapFromMemCache(int resId) { return getBitmapFromMemCache("res:" + resId); } private void addBitmapToMemCache(int resId, Bitmap bitmap) { addBitmapToMemCache("res:" + resId, bitmap); } public void clear() { mMemCache.evictAll(); } public static Bitmap GetFromResource(View v, int resId) { BitmapCache cache = BitmapCache.getInstance(); Bitmap bitmap = cache.getBitmapFromMemCache(resId); if (bitmap == null) { bitmap = BitmapFactory.decodeResource(v.getResources(), resId); cache.addBitmapToMemCache(resId, bitmap); } return bitmap; } }