Java tutorial
/* * Copyright (C) 2012 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.zlk.bigdemo.freeza.image.cache; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.CompressFormat; import android.support.v4.app.FragmentActivity; import android.support.v4.util.LruCache; import android.text.TextUtils; import com.zlk.bigdemo.android.volley.toolbox.ImageLoader.ImageCache; import com.zlk.bigdemo.freeza.util.Md5Util; /** * This class holds our bitmap caches (memory and disk). */ public class MagicImageCache implements ImageCache { // Default memory cache size private static final int DEFAULT_MEM_CACHE_SIZE = (int) (Runtime.getRuntime().maxMemory() / 12); // // Default disk cache size private static final int DEFAULT_DISK_CACHE_SIZE = 1024 * 1024 * 100; // 100MB // Compression settings when writing images to disk cache private static final CompressFormat DEFAULT_COMPRESS_FORMAT = CompressFormat.JPEG; private static final int DEFAULT_COMPRESS_QUALITY = 70; // Constants to easily toggle various caches private static final boolean DEFAULT_MEM_CACHE_ENABLED = true; private static final boolean DEFAULT_DISK_CACHE_ENABLED = true; private static final boolean DEFAULT_CLEAR_DISK_CACHE_ON_START = false; private LruCache<String, Bitmap> mMemoryCache; private static MagicImageCache imageCache; public MagicImageCache(Context context, ImageCacheParams cacheParams) { init(context, cacheParams); } /** * Creating a new ImageCache object using the default parameters. * * @param context * The context to use * @param uniqueName * A unique name that will be appended to the cache directory */ public MagicImageCache(Context context, String uniqueName) { init(context, new ImageCacheParams(uniqueName)); } /** * Find and return an existing ImageCache stored in a {@link RetainFragment} * , if not found a new one is created with defaults and saved to a * {@link RetainFragment}. * * @param activity * The calling {@link FragmentActivity} * @param uniqueName * A unique name to append to the cache directory * @return An existing retained ImageCache object or a new one if one did * not exist. */ public static MagicImageCache findOrCreateCache(final Context context, final String uniqueName) { return findOrCreateCache(context, new ImageCacheParams(uniqueName)); } /** * Find and return an existing ImageCache stored in a {@link RetainFragment} * , if not found a new one is created using the supplied params and saved * to a {@link RetainFragment}. * * @param activity * The calling {@link FragmentActivity} * @param cacheParams * The cache parameters to use if creating the ImageCache * @return An existing retained ImageCache object or a new one if one did * not exist */ public static synchronized MagicImageCache findOrCreateCache(final Context context, ImageCacheParams cacheParams) { if (imageCache == null) { imageCache = new MagicImageCache(context, cacheParams); } return imageCache; } /** * Initialize the cache, providing all parameters. * * @param context * The context to use * @param cacheParams * The cache parameters to initialize the cache */ private void init(Context context, ImageCacheParams cacheParams) { // Set up memory cache if (cacheParams.memoryCacheEnabled) { mMemoryCache = new LruCache<String, Bitmap>(cacheParams.memCacheSize) { /** * Measure item size in bytes rather than units which is more * practical for a bitmap cache */ @Override protected int sizeOf(String key, Bitmap bitmap) { int size = bitmap.getRowBytes() * bitmap.getHeight(); // WxLog.d("setting", "Bitmap size:" + size); return size; } }; } } /** * Get from memory cache. * * @param data * Unique identifier for which item to get * @return The bitmap if found in cache, null otherwise */ public Bitmap getBitmapFromMemCache(String data) { if (mMemoryCache != null) { final Bitmap memBitmap = mMemoryCache.get(data); if (memBitmap != null) { // if (BuildConfig.DEBUG) { // WxLog.d(TAG, "Memory cache hit"); // } return memBitmap; } } return null; } /** * Get from disk cache. * * @param data * Unique identifier for which item to get * @return The bitmap if found in cache, null otherwise */ public void clearCaches() { mMemoryCache.evictAll(); } /** * A holder class that contains cache parameters. */ public static class ImageCacheParams { public String uniqueName; public int memCacheSize = DEFAULT_MEM_CACHE_SIZE; public int diskCacheSize = DEFAULT_DISK_CACHE_SIZE; public CompressFormat compressFormat = DEFAULT_COMPRESS_FORMAT; public int compressQuality = DEFAULT_COMPRESS_QUALITY; public boolean memoryCacheEnabled = DEFAULT_MEM_CACHE_ENABLED; public boolean diskCacheEnabled = DEFAULT_DISK_CACHE_ENABLED; public boolean clearDiskCacheOnStart = DEFAULT_CLEAR_DISK_CACHE_ON_START; public ImageCacheParams(String uniqueName) { this.uniqueName = uniqueName; } } @Override public Bitmap getBitmap(final String url) { final String md5Name = Md5Util.getStringMD5(url); Bitmap memBitmap = getBitmapFromMemCache(md5Name); if (memBitmap != null) { return memBitmap; } return null; } @Override public void putBitmap(String url, Bitmap bitmap) { String md5Name = Md5Util.getStringMD5(url); if (md5Name == null || bitmap == null) { return; } if (mMemoryCache != null && mMemoryCache.get(md5Name) == null) { mMemoryCache.put(md5Name, bitmap); } } public void removeBitmap(String key) { if (TextUtils.isEmpty(key)) { return; } String md5Name = Md5Util.getStringMD5(key); if (mMemoryCache != null) { mMemoryCache.remove(md5Name); } } }