Android缓存 _Android

一年好景君须记，最是橙黄橘绿时。这篇文章主要讲述Android缓存相关的知识，希望能为你提供帮助。
一个利用内存缓存和磁盘缓存图片的例子

public class BitmapCache {public static final String TAG = "debug"; private LruCache< String, Bitmap> mBitmapCache; public BitmapCache() { // 获取到可用内存的最大值，使用内存超出这个值会引起OutOfMemory异常。 // LruCache 使用的缓存值，使用系统分配给应用程序大小的 1/8 int maxSize = (int) (Runtime.getRuntime().maxMemory() / 8); mBitmapCache = new LruCache< String, Bitmap> (maxSize) { @Override protected int sizeOf(String key, Bitmap bitmap) { return bitmap.getByteCount(); } }; }public void add(String key, Bitmap value) { mBitmapCache.put(key, value); }public void remove(String key) { mBitmapCache.remove(key); }public Bitmap get(String key) { return mBitmapCache.get(key); }public boolean containsKey(String key) { return mBitmapCache.get(key) != null; }public static long toMB(long byteOfSize) { return byteOfSize > > 20; } }

import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.util.Log; public class BitmapDiskCache {private static final String TAG = "debug"; private static final int DISK_CACHE_INDEX = 0; private static final int DISK_CACHE_COUNT = 1; private static final int VERSION = 1; private DiskLruCache mDiskLruCache; private DiskLruCache.Editor mEditor; public BitmapDiskCache(File diskCacheDir, long nDiskCacheSize) { if (!diskCacheDir.exists()) { diskCacheDir.mkdirs(); }try { mDiskLruCache = DiskLruCache.open(diskCacheDir, VERSION, DISK_CACHE_COUNT, nDiskCacheSize); } catch (IOException e) { Log.e(TAG, "", e); } }public InputStream getInputStream(String key) { if (null != mDiskLruCache) { try { DiskLruCache.Snapshot snapshot = mDiskLruCache.get(key); if (null != snapshot) { return snapshot.getInputStream(DISK_CACHE_INDEX); } } catch (IOException e) { Log.e(TAG, "", e); } } return null; }public OutputStream beginEdit(String key) throws IOException { if (null != mDiskLruCache) { mEditor = mDiskLruCache.edit(key); if (null != mEditor) { return mEditor.newOutputStream(DISK_CACHE_INDEX); } } return null; }public void endEdit(Boolean isSuccess) throws IOException { if (null != mEditor) { if (isSuccess) { mEditor.commit(); } else { mEditor.abort(); } mEditor = null; } }public void flush() { if (null != mDiskLruCache) { try { mDiskLruCache.flush(); } catch (IOException e) { Log.e(TAG, "", e); } } } }

【Android缓存】

import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.Closeable; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.lang.ref.SoftReference; import java.net.HttpURLConnection; import java.net.URL; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.concurrent.Executor; import java.util.concurrent.LinkedBlockingQueue; import java.util.concurrent.ThreadFactory; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicInteger; import android.content.Context; import android.graphics.Bitmap; import android.os.Build; import android.os.Build.VERSION_CODES; import android.os.Environment; import android.os.Handler; import android.os.Looper; import android.os.Message; import android.os.StatFs; import android.util.Log; import android.widget.ImageView; public class BitmapLoader {private static final String TAG = "debug"; private static final long DISK_CACHE_SIZE = 1024 * 1024 * 50; private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors(); private static final int CORE_POOL_SIZE = CPU_COUNT + 1; private static final int MAX_MUM_POOL_SIZE = CPU_COUNT * 2 + 1; private static final long KEEP_ALIVE_TIME = 10; private static final int IO_BUFFER_SIZE = 1024 * 8; private static final int MESSAGE_POST_RESULT = 1000; private BitmapCache mBitmapCache; private BitmapDiskCache mBitmapDiskCache; private static ThreadFactory sThreadFactory = new ThreadFactory() { private AtomicInteger mCounter = new AtomicInteger(1); @Override public Thread newThread(Runnable r) { return new Thread(r, "BitmapLoader#" + mCounter.getAndIncrement()); } }; private static Executor sThreadPoolExecutor = new ThreadPoolExecutor(CORE_POOL_SIZE, MAX_MUM_POOL_SIZE, KEEP_ALIVE_TIME, TimeUnit.SECONDS, new LinkedBlockingQueue< Runnable> (), sThreadFactory); class LoaderResult { SoftReference< ImageView> mImageViewRef; Bitmap mBitmap; String mUri; public LoaderResult(ImageView imageView, String uri, Bitmap bitmap) { mImageViewRef = new SoftReference< ImageView> (imageView); mUri = uri; mBitmap = bitmap; } }private Handler mMainHandler = new Handler(Looper.getMainLooper()) { @Override public void handleMessage(Message msg) { LoaderResult result = (LoaderResult) msg.obj; ImageView imageView = result.mImageViewRef.get(); if (null != imageView) { imageView.setImageBitmap(result.mBitmap); String uri = (String) imageView.getTag(); if (uri.equals(result.mUri)) { imageView.setImageBitmap(result.mBitmap); } else { Log.w(TAG, "set image bitmap, but url has changed, ignored!"); } } else { Log.w(TAG, "set image bitmap, ImageView released, ignored!"); } }; }; public BitmapLoader(Context context) {mBitmapCache = new BitmapCache(); File diskCacheDir = new File(getDiskCacheDir(context, "bmp")); if (!diskCacheDir.exists()) { diskCacheDir.mkdirs(); } if (getUsableSpace(diskCacheDir) > DISK_CACHE_SIZE) { mBitmapDiskCache = new BitmapDiskCache(diskCacheDir, DISK_CACHE_SIZE); } }public void bindBitmap(final String uri, final ImageView imageView, final int reqWidth, final int reqHeight) { String key = hashKeyFormUrl(uri); Bitmap bitmap = mBitmapCache.get(key); if (null != bitmap) { Log.d(TAG, "load from memory cache on bind"); imageView.setImageBitmap(bitmap); return; }imageView.setTag(uri); Runnable loadBitmapTask = new Runnable() { @Override public void run() { Log.d(TAG, Thread.currentThread().getName() + " run"); Bitmap bitmap = loadBitmap(uri, reqWidth, reqHeight); if (bitmap != null) { LoaderResult result = new LoaderResult(imageView, uri, bitmap); mMainHandler.obtainMessage(MESSAGE_POST_RESULT, result).sendToTarget(); } } }; sThreadPoolExecutor.execute(loadBitmapTask); }public Bitmap loadBitmap(String uri, int reqWidth, int reqHeight) { String key = hashKeyFormUrl(uri); Bitmap bitmap = mBitmapCache.get(key); if (null != bitmap) { Log.d(TAG, "load from memory cache"); return bitmap; }try { bitmap = loadBitmapFromDiskCache(key, reqWidth, reqHeight); if (null != bitmap) { Log.d(TAG, "load from disk cache"); return bitmap; } bitmap = loadBitmapFromHttp(uri, reqWidth, reqHeight); if (null != bitmap) { Log.d(TAG, "load from http"); } } catch (IOException e) { Log.e(TAG, "", e); }if (null == bitmap) { bitmap = downloadBitmapFromUrl(uri, reqWidth, reqHeight); if (null != bitmap) { mBitmapCache.add(key, bitmap); Log.d(TAG, "load from url"); } }return bitmap; }private Bitmap loadBitmapFromDiskCache(String key, int reqWidth, int reqHeight) throws IOException { if (Looper.myLooper() == Looper.getMainLooper()) { Log.w(TAG, "load bitmap from UI Thread, it‘s not recommended!"); } if (mBitmapDiskCache == null) { return null; }Bitmap bitmap = null; InputStream is = mBitmapDiskCache.getInputStream(key); if (null != is) { bitmap = BitmapTools.decodeSampledBitmapFromInputStream(is, reqWidth, reqHeight); if (bitmap != null) { mBitmapCache.add(key, bitmap); } } return bitmap; }private Bitmap loadBitmapFromHttp(String url, int reqWidth, int reqHeight) throws IOException { if (Looper.myLooper() == Looper.getMainLooper()) { throw new RuntimeException("can not visit network from UI Thread."); } if (mBitmapDiskCache == null) { return null; }String key = hashKeyFormUrl(url); OutputStream os = mBitmapDiskCache.beginEdit(key); if (null != os) { if (downloadUrlToStream(url, os)) { mBitmapDiskCache.endEdit(true); } else { mBitmapDiskCache.endEdit(false); } mBitmapDiskCache.flush(); } return loadBitmapFromDiskCache(key, reqWidth, reqHeight); }private Bitmap downloadBitmapFromUrl(String urlString, int reqWidth, int reqHeight) { HttpURLConnection urlConnection = null; BufferedInputStream in = null; try { final URL url = new URL(urlString); urlConnection = (HttpURLConnection) url.openConnection(); in = new BufferedInputStream(urlConnection.getInputStream(), IO_BUFFER_SIZE); return BitmapTools.decodeSampledBitmapFromInputStream(in, reqWidth, reqHeight); } catch (IOException e) { Log.e(TAG, "Error in downloadBitmap: ", e); } finally { if (urlConnection != null) { urlConnection.disconnect(); } close(in); } return null; }private boolean downloadUrlToStream(String urlString, OutputStream outputStream) { HttpURLConnection urlConnection = null; BufferedOutputStream out = null; BufferedInputStream in = null; try { final URL url = new URL(urlString); urlConnection = (HttpURLConnection) url.openConnection(); in = new BufferedInputStream(urlConnection.getInputStream(), IO_BUFFER_SIZE); out = new BufferedOutputStream(outputStream, IO_BUFFER_SIZE); int b; while ((b = in.read()) != -1) { out.write(b); } return true; } catch (IOException e) { Log.e(TAG, "downloadBitmap failed.", e); } finally { if (urlConnection != null) { urlConnection.disconnect(); } close(out); close(in); } return false; }private void close(Closeable obj) { if (null != obj) { try { obj.close(); } catch (IOException e) { Log.e(TAG, "", e); } } }private String hashKeyFormUrl(String url) { String cacheKey; try { final MessageDigest md5Digest = MessageDigest.getInstance("MD5"); md5Digest.update(url.getBytes()); cacheKey = bytesToHexString(md5Digest.digest()); } catch (NoSuchAlgorithmException e) { cacheKey = String.valueOf(url.hashCode()); } return cacheKey; }private String bytesToHexString(byte[] bytes) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < bytes.length; i++) { String hex = Integer.toHexString(0xFF & bytes[i]); if (hex.length() == 1) { sb.append(‘0‘); } sb.append(hex); } return sb.toString(); }private String getDiskCacheDir(Context context, String uniqueName) { boolean isAvailable = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); final String cachePath; if (isAvailable) { cachePath = context.getExternalCacheDir().getPath(); } else { cachePath = context.getCacheDir().getPath(); }return (cachePath + File.separator + uniqueName); }private long getUsableSpace(File path) { if (Build.VERSION.SDK_INT > = VERSION_CODES.GINGERBREAD) { return path.getUsableSpace(); } final StatFs stats = new StatFs(path.getPath()); return stats.getBlockSizeLong() * stats.getAvailableBlocksLong(); } }

/* * Copyright (C) 2011 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.bitmap; import java.io.BufferedInputStream; import java.io.BufferedWriter; import java.io.Closeable; import java.io.EOFException; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.FilterOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Reader; import java.io.StringWriter; import java.io.Writer; import java.lang.reflect.Array; import java.nio.charset.Charset; import java.util.ArrayList; import java.util.Arrays; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; import java.util.concurrent.Callable; import java.util.concurrent.ExecutorService; import java.util.concurrent.LinkedBlockingQueue; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; /** ****************************************************************************** * Taken from the JB source code, can be found in: * libcore/luni/src/main/java/libcore/io/DiskLruCache.java * or direct link: * https://android.googlesource.com/platform/libcore/+/android-4.1.1_r1/luni/src/main/java/libcore/io/DiskLruCache.java ****************************************************************************** * * A cache that uses a bounded amount of space on a filesystem. Each cache * entry has a string key and a fixed number of values. Values are byte * sequences, accessible as streams or files. Each value must be between {@code * 0} and {@code Integer.MAX_VALUE} bytes in length. * * The cache stores its data in a directory on the filesystem. This * directory must be exclusive to the cache; the cache may delete or overwrite * files from its directory. It is an error for multiple processes to use the * same cache directory at the same time. * * This cache limits the number of bytes that it will store on the * filesystem. When the number of stored bytes exceeds the limit, the cache will * remove entries in the background until the limit is satisfied. The limit is * not strict: the cache may temporarily exceed it while waiting for files to be * deleted. The limit does not include filesystem overhead or the cache * journal so space-sensitive applications should set a conservative limit. * * Clients call {@link #edit} to create or update the values of an entry. An * entry may have only one editor at one time; if a value is not available to be * edited then {@link #edit} will return null. * < ul> *< li> When an entry is being created it is necessary to *supply a full set of values; the empty value should be used as a *placeholder if necessary. *< li> When an entry is being edited , it is not necessary *to supply data for every value; values default to their previous *value. * < /ul> * Every {@link #edit} call must be matched by a call to {@link Editor#commit} * or {@link Editor#abort}. Committing is atomic: a read observes the full set * of values as they were before or after the commit, but never a mix of values. * * Clients call {@link #get} to read a snapshot of an entry. The read will * observe the value at the time that {@link #get} was called. Updates and * removals after the call do not impact ongoing reads. * * This class is tolerant of some I/O errors. If files are missing from the * filesystem, the corresponding entries will be dropped from the cache. If * an error occurs while writing a cache value, the edit will fail silently. * Callers should handle other problems by catching {@code IOException} and * responding appropriately. */ public final class DiskLruCache implements Closeable { static final String JOURNAL_FILE = "journal"; static final String JOURNAL_FILE_TMP = "journal.tmp"; static final String MAGIC = "libcore.io.DiskLruCache"; static final String VERSION_1 = "1"; static final long ANY_SEQUENCE_NUMBER = -1; private static final String CLEAN = "CLEAN"; private static final String DIRTY = "DIRTY"; private static final String REMOVE = "REMOVE"; private static final String READ = "READ"; private static final Charset UTF_8 = Charset.forName("UTF-8"); private static final int IO_BUFFER_SIZE = 8 * 1024; /* * This cache uses a journal file named "journal". A typical journal file * looks like this: *libcore.io.DiskLruCache *1 *100 *2 * *CLEAN 3400330d1dfc7f3f7f4b8d4d803dfcf6 832 21054 *DIRTY 335c4c6028171cfddfbaae1a9c313c52 *CLEAN 335c4c6028171cfddfbaae1a9c313c52 3934 2342 *REMOVE 335c4c6028171cfddfbaae1a9c313c52 *DIRTY 1ab96a171faeeee38496d8b330771a7a *CLEAN 1ab96a171faeeee38496d8b330771a7a 1600 234 *READ 335c4c6028171cfddfbaae1a9c313c52 *READ 3400330d1dfc7f3f7f4b8d4d803dfcf6 * * The first five lines of the journal form its header. They are the * constant string "libcore.io.DiskLruCache", the disk cache‘s version, * the application‘s version, the value count, and a blank line. * * Each of the subsequent lines in the file is a record of the state of a * cache entry. Each line contains space-separated values: a state, a key, * and optional state-specific values. *o DIRTY lines track that an entry is actively being created or updated. *Every successful DIRTY action should be followed by a CLEAN or REMOVE *action. DIRTY lines without a matching CLEAN or REMOVE indicate that *temporary files may need to be deleted. *o CLEAN lines track a cache entry that has been successfully published *and may be read. A publish line is followed by the lengths of each of *its values. *o READ lines track accesses for LRU. *o REMOVE lines track entries that have been deleted. * * The journal file is appended to as cache operations occur. The journal may * occasionally be compacted by dropping redundant lines. A temporary file named * "journal.tmp" will be used during compaction; that file should be deleted if * it exists when the cache is opened. */private final File directory; private final File journalFile; private final File journalFileTmp; private final int appVersion; private final long maxSize; private final int valueCount; private long size = 0; private Writer journalWriter; private final LinkedHashMap< String, Entry> lruEntries = new LinkedHashMap< String, Entry> (0, 0.75f, true); private int redundantOpCount; /** * To differentiate between old and current snapshots, each entry is given * a sequence number each time an edit is committed. A snapshot is stale if * its sequence number is not equal to its entry‘s sequence number. */ private long nextSequenceNumber = 0; /* From java.util.Arrays */ @SuppressWarnings("unchecked") private static < T> T[] copyOfRange(T[] original, int start, int end) { final int originalLength = original.length; // For exception priority compatibility. if (start > end) { throw new IllegalArgumentException(); } if (start < 0 || start > originalLength) { throw new ArrayIndexOutOfBoundsException(); } final int resultLength = end - start; final int copyLength = Math.min(resultLength, originalLength - start); final T[] result = (T[]) Array .newInstance(original.getClass().getComponentType(), resultLength); System.arraycopy(original, start, result, 0, copyLength); return result; }/** * Returns the remainder of ‘reader‘ as a string, closing it when done. */ public static String readFully(Reader reader) throws IOException { try { StringWriter writer = new StringWriter(); char[] buffer = new char[1024]; int count; while ((count = reader.read(buffer)) != -1) { writer.write(buffer, 0, count); } return writer.toString(); } finally { reader.close(); } }/** * Returns the ASCII characters up to but not including the next "\r\n", or * "\n". * * @throws java.io.EOFException if the stream is exhausted before the next newline *character. */ public static String readAsciiLine(InputStream in) throws IOException { // TODO: support UTF-8 here insteadStringBuilder result = new StringBuilder(80); while (true) { int c = in.read(); if (c == -1) { throw new EOFException(); } else if (c == ‘\n‘) { break; }result.append((char) c); } int length = result.length(); if (length > 0 & & result.charAt(length - 1) == ‘\r‘) { result.setLength(length - 1); } return result.toString(); }/** * Closes ‘closeable‘, ignoring any checked exceptions. Does nothing if ‘closeable‘ is null. */ public static void closeQuietly(Closeable closeable) { if (closeable != null) { try { closeable.close(); } catch (RuntimeException rethrown) { throw rethrown; } catch (Exception ignored) { } } }/** * Recursively delete everything in {@code dir}. */ // TODO: this should specify paths as Strings rather than as Files public static void deleteContents(File dir) throws IOException { File[] files = dir.listFiles(); if (files == null) { throw new IllegalArgumentException("not a directory: " + dir); } for (File file : files) { if (file.isDirectory()) { deleteContents(file); } if (!file.delete()) { throw new IOException("failed to delete file: " + file); } } }/** This cache uses a single background thread to evict entries. */ private final ExecutorService executorService = new ThreadPoolExecutor(0, 1, 60L, TimeUnit.SECONDS, new LinkedBlockingQueue< Runnable> ()); private final Callable< Void> cleanupCallable = new Callable< Void> () { @Override public Void call() throws Exception { synchronized (DiskLruCache.this) { if (journalWriter == null) { return null; // closed } trimToSize(); if (journalRebuildRequired()) { rebuildJournal(); redundantOpCount = 0; } } return null; } }; private DiskLruCache(File directory, int appVersion, int valueCount, long maxSize) { this.directory = directory; this.appVersion = appVersion; this.journalFile = new File(directory, JOURNAL_FILE); this.journalFileTmp = new File(directory, JOURNAL_FILE_TMP); this.valueCount = valueCount; this.maxSize = maxSize; }/** * Opens the cache in {@code directory}, creating a cache if none exists * there. * * @param directory a writable directory * @param appVersion * @param valueCount the number of values per cache entry. Must be positive. * @param maxSize the maximum number of bytes this cache should use to store * @throws java.io.IOException if reading or writing the cache directory fails */ public static DiskLruCache open(File directory, int appVersion, int valueCount, long maxSize) throws IOException { if (maxSize < = 0) { throw new IllegalArgumentException("maxSize < = 0"); } if (valueCount < = 0) { throw new IllegalArgumentException("valueCount < = 0"); }// prefer to pick up where we left off DiskLruCache cache = new DiskLruCache(directory, appVersion, valueCount, maxSize); if (cache.journalFile.exists()) { try { cache.readJournal(); cache.processJournal(); cache.journalWriter = new BufferedWriter(new FileWriter(cache.journalFile, true), IO_BUFFER_SIZE); return cache; } catch (IOException journalIsCorrupt) { //System.logW("DiskLruCache " + directory + " is corrupt: " //+ journalIsCorrupt.getMessage() + ", removing"); cache.delete(); } }// create a new empty cache directory.mkdirs(); cache = new DiskLruCache(directory, appVersion, valueCount, maxSize); cache.rebuildJournal(); return cache; }private void readJournal() throws IOException { InputStream in = new BufferedInputStream(new FileInputStream(journalFile), IO_BUFFER_SIZE); try { String magic = readAsciiLine(in); String version = readAsciiLine(in); String appVersionString = readAsciiLine(in); String valueCountString = readAsciiLine(in); String blank = readAsciiLine(in); if (!MAGIC.equals(magic) || !VERSION_1.equals(version) || !Integer.toString(appVersion).equals(appVersionString) || !Integer.toString(valueCount).equals(valueCountString) || !"".equals(blank)) { throw new IOException("unexpected journal header: [" + magic + ", " + version + ", " + valueCountString + ", " + blank + "]"); }while (true) { try { readJournalLine(readAsciiLine(in)); } catch (EOFException endOfJournal) { break; } } } finally { closeQuietly(in); } }private void readJournalLine(String line) throws IOException { String[] parts = line.split(" "); if (parts.length < 2) { throw new IOException("unexpected journal line: " + line); }String key = parts[1]; if (parts[0].equals(REMOVE) & & parts.length == 2) { lruEntries.remove(key); return; }Entry entry = lruEntries.get(key); if (entry == null) { entry = new Entry(key); lruEntries.put(key, entry); }if (parts[0].equals(CLEAN) & & parts.length == 2 + valueCount) { entry.readable = true; entry.currentEditor = null; entry.setLengths(copyOfRange(parts, 2, parts.length)); } else if (parts[0].equals(DIRTY) & & parts.length == 2) { entry.currentEditor = new Editor(entry); } else if (parts[0].equals(READ) & & parts.length == 2) { // this work was already done by calling lruEntries.get() } else { throw new IOException("unexpected journal line: " + line); } }/** * Computes the initial size and collects garbage as a part of opening the * cache. Dirty entries are assumed to be inconsistent and will be deleted. */ private void processJournal() throws IOException { deleteIfExists(journalFileTmp); for (Iterator< Entry> i = lruEntries.values().iterator(); i.hasNext(); ) { Entry entry = i.next(); if (entry.currentEditor == null) { for (int t = 0; t < valueCount; t++) { size += entry.lengths[t]; } } else { entry.currentEditor = null; for (int t = 0; t < valueCount; t++) { deleteIfExists(entry.getCleanFile(t)); deleteIfExists(entry.getDirtyFile(t)); } i.remove(); } } }/** * Creates a new journal that omits redundant information. This replaces the * current journal if it exists. */ private synchronized void rebuildJournal() throws IOException { if (journalWriter != null) { journalWriter.close(); }Writer writer = new BufferedWriter(new FileWriter(journalFileTmp), IO_BUFFER_SIZE); writer.write(MAGIC); writer.write("\n"); writer.write(VERSION_1); writer.write("\n"); writer.write(Integer.toString(appVersion)); writer.write("\n"); writer.write(Integer.toString(valueCount)); writer.write("\n"); writer.write("\n"); for (Entry entry : lruEntries.values()) { if (entry.currentEditor != null) { writer.write(DIRTY + ‘ ‘ + entry.key + ‘\n‘); } else { writer.write(CLEAN + ‘ ‘ + entry.key + entry.getLengths() + ‘\n‘); } }writer.close(); journalFileTmp.renameTo(journalFile); journalWriter = new BufferedWriter(new FileWriter(journalFile, true), IO_BUFFER_SIZE); }private static void deleteIfExists(File file) throws IOException { //try { //Libcore.os.remove(file.getPath()); //} catch (ErrnoException errnoException) { //if (errnoException.errno != OsConstants.ENOENT) { //throw errnoException.rethrowAsIOException(); //} //} if (file.exists() & & !file.delete()) { throw new IOException(); } }/** * Returns a snapshot of the entry named {@code key}, or null if it doesn‘t * exist is not currently readable. If a value is returned, it is moved to * the head of the LRU queue. */ public synchronized Snapshot get(String key) throws IOException { checkNotClosed(); validateKey(key); Entry entry = lruEntries.get(key); if (entry == null) { return null; }if (!entry.readable) { return null; }/* * Open all streams eagerly to guarantee that we see a single published * snapshot. If we opened streams lazily then the streams could come * from different edits. */ InputStream[] ins = new InputStream[valueCount]; try { for (int i = 0; i < valueCount; i++) { ins[i] = new FileInputStream(entry.getCleanFile(i)); } } catch (FileNotFoundException e) { // a file must have been deleted manually! return null; }redundantOpCount++; journalWriter.append(READ + ‘ ‘ + key + ‘\n‘); if (journalRebuildRequired()) { executorService.submit(cleanupCallable); }return new Snapshot(key, entry.sequenceNumber, ins); }/** * Returns an editor for the entry named {@code key}, or null if another * edit is in progress. */ public Editor edit(String key) throws IOException { return edit(key, ANY_SEQUENCE_NUMBER); }private synchronized Editor edit(String key, long expectedSequenceNumber) throws IOException { checkNotClosed(); validateKey(key); Entry entry = lruEntries.get(key); if (expectedSequenceNumber != ANY_SEQUENCE_NUMBER & & (entry == null || entry.sequenceNumber != expectedSequenceNumber)) { return null; // snapshot is stale } if (entry == null) { entry = new Entry(key); lruEntries.put(key, entry); } else if (entry.currentEditor != null) { return null; // another edit is in progress }Editor editor = new Editor(entry); entry.currentEditor = editor; // flush the journal before creating files to prevent file leaks journalWriter.write(DIRTY + ‘ ‘ + key + ‘\n‘); journalWriter.flush(); return editor; }/** * Returns the directory where this cache stores its data. */ public File getDirectory() { return directory; }/** * Returns the maximum number of bytes that this cache should use to store * its data. */ public long maxSize() { return maxSize; }/** * Returns the number of bytes currently being used to store the values in * this cache. This may be greater than the max size if a background * deletion is pending. */ public synchronized long size() { return size; }private synchronized void completeEdit(Editor editor, boolean success) throws IOException { Entry entry = editor.entry; if (entry.currentEditor != editor) { throw new IllegalStateException(); }// if this edit is creating the entry for the first time, every index must have a value if (success & & !entry.readable) { for (int i = 0; i < valueCount; i++) { if (!entry.getDirtyFile(i).exists()) { editor.abort(); throw new IllegalStateException("edit didn‘t create file " + i); } } }for (int i = 0; i < valueCount; i++) { File dirty = entry.getDirtyFile(i); if (success) { if (dirty.exists()) { File clean = entry.getCleanFile(i); dirty.renameTo(clean); long oldLength = entry.lengths[i]; long newLength = clean.length(); entry.lengths[i] = newLength; size = size - oldLength + newLength; } } else { deleteIfExists(dirty); } }redundantOpCount++; entry.currentEditor = null; if (entry.readable | success) { entry.readable = true; journalWriter.write(CLEAN + ‘ ‘ + entry.key + entry.getLengths() + ‘\n‘); if (success) { entry.sequenceNumber = nextSequenceNumber++; } } else { lruEntries.remove(entry.key); journalWriter.write(REMOVE + ‘ ‘ + entry.key + ‘\n‘); }if (size > maxSize || journalRebuildRequired()) { executorService.submit(cleanupCallable); } }/** * We only rebuild the journal when it will halve the size of the journal * and eliminate at least 2000 ops. */ private boolean journalRebuildRequired() { final int REDUNDANT_OP_COMPACT_THRESHOLD = 2000; return redundantOpCount > = REDUNDANT_OP_COMPACT_THRESHOLD & & redundantOpCount > = lruEntries.size(); }/** * Drops the entry for {@code key} if it exists and can be removed. Entries * actively being edited cannot be removed. * * @return true if an entry was removed. */ public synchronized boolean remove(String key) throws IOException { checkNotClosed(); validateKey(key); Entry entry = lruEntries.get(key); if (entry == null || entry.currentEditor != null) { return false; }for (int i = 0; i < valueCount; i++) { File file = entry.getCleanFile(i); if (!file.delete()) { throw new IOException("failed to delete " + file); } size -= entry.lengths[i]; entry.lengths[i] = 0; }redundantOpCount++; journalWriter.append(REMOVE + ‘ ‘ + key + ‘\n‘); lruEntries.remove(key); if (journalRebuildRequired()) { executorService.submit(cleanupCallable); }return true; }/** * Returns true if this cache has been closed. */ public boolean isClosed() { return journalWriter == null; }private void checkNotClosed() { if (journalWriter == null) { throw new IllegalStateException("cache is closed"); } }/** * Force buffered operations to the filesystem. */ public synchronized void flush() throws IOException { checkNotClosed(); trimToSize(); journalWriter.flush(); }/** * Closes this cache. Stored values will remain on the filesystem. */ public synchronized void close() throws IOException { if (journalWriter == null) { return; // already closed } for (Entry entry : new ArrayList< Entry> (lruEntries.values())) { if (entry.currentEditor != null) { entry.currentEditor.abort(); } } trimToSize(); journalWriter.close(); journalWriter = null; }private void trimToSize() throws IOException { while (size > maxSize) { //Map.Entry< String, Entry> toEvict = lruEntries.eldest(); final Map.Entry< String, Entry> toEvict = lruEntries.entrySet().iterator().next(); remove(toEvict.getKey()); } }/** * Closes the cache and deletes all of its stored values. This will delete * all files in the cache directory including files that weren‘t created by * the cache. */ public void delete() throws IOException { close(); deleteContents(directory); }private void validateKey(String key) { if (key.contains(" ") || key.contains("\n") || key.contains("\r")) { throw new IllegalArgumentException( "keys must not contain spaces or newlines: \"" + key + "\""); } }private static String inputStreamToString(InputStream in) throws IOException { return readFully(new InputStreamReader(in, UTF_8)); }/** * A snapshot of the values for an entry. */ public final class Snapshot implements Closeable { private final String key; private final long sequenceNumber; private final InputStream[] ins; private Snapshot(String key, long sequenceNumber, InputStream[] ins) { this.key = key; this.sequenceNumber = sequenceNumber; this.ins = ins; }/** * Returns an editor for this snapshot‘s entry, or null if either the * entry has changed since this snapshot was created or if another edit * is in progress. */ public Editor edit() throws IOException { return DiskLruCache.this.edit(key, sequenceNumber); }/** * Returns the unbuffered stream with the value for {@code index}. */ public InputStream getInputStream(int index) { return ins[index]; }/** * Returns the string value for {@code index}. */ public String getString(int index) throws IOException { return inputStreamToString(getInputStream(index)); }@Override public void close() { for (InputStream in : ins) { closeQuietly(in); } } }/** * Edits the values for an entry. */ public final class Editor { private final Entry entry; private boolean hasErrors; private Editor(Entry entry) { this.entry = entry; }/** * Returns an unbuffered input stream to read the last committed value, * or null if no value has been committed. */ public InputStream newInputStream(int index) throws IOException { synchronized (DiskLruCache.this) { if (entry.currentEditor != this) { throw new IllegalStateException(); } if (!entry.readable) { return null; } return new FileInputStream(entry.getCleanFile(index)); } }/** * Returns the last committed value as a string, or null if no value * has been committed. */ public String getString(int index) throws IOException { InputStream in = newInputStream(index); return in != null ? inputStreamToString(in) : null; }/** * Returns a new unbuffered output stream to write the value at * {@code index}. If the underlying output stream encounters errors * when writing to the filesystem, this edit will be aborted when * {@link #commit} is called. The returned output stream does not throw * IOExceptions. */ public OutputStream newOutputStream(int index) throws IOException { synchronized (DiskLruCache.this) { if (entry.currentEditor != this) { throw new IllegalStateException(); } return new FaultHidingOutputStream(new FileOutputStream(entry.getDirtyFile(index))); } }/** * Sets the value at {@code index} to {@code value}. */ public void set(int index, String value) throws IOException { Writer writer = null; try { writer = new OutputStreamWriter(newOutputStream(index), UTF_8); writer.write(value); } finally { closeQuietly(writer); } }/** * Commits this edit so it is visible to readers.This releases the * edit lock so another edit may be started on the same key. */ public void commit() throws IOException { if (hasErrors) { completeEdit(this, false); remove(entry.key); // the previous entry is stale } else { completeEdit(this, true); } }/** * Aborts this edit. This releases the edit lock so another edit may be * started on the same key. */ public void abort() throws IOException { completeEdit(this, false); }private class FaultHidingOutputStream extends FilterOutputStream { private FaultHidingOutputStream(OutputStream out) { super(out); }@Override public void write(int oneByte) { try { out.write(oneByte); } catch (IOException e) { hasErrors = true; } }@Override public void write(byte[] buffer, int offset, int length) { try { out.write(buffer, offset, length); } catch (IOException e) { hasErrors = true; } }@Override public void close() { try { out.close(); } catch (IOException e) { hasErrors = true; } }@Override public void flush() { try { out.flush(); } catch (IOException e) { hasErrors = true; } } } }private final class Entry { private final String key; /** Lengths of this entry‘s files. */ private final long[] lengths; /** True if this entry has ever been published */ private boolean readable; /** The ongoing edit or null if this entry is not being edited. */ private Editor currentEditor; /** The sequence number of the most recently committed edit to this entry. */ private long sequenceNumber; private Entry(String key) { this.key = key; this.lengths = new long[valueCount]; }public String getLengths() throws IOException { StringBuilder result = new StringBuilder(); for (long size : lengths) { result.append(‘ ‘).append(size); } return result.toString(); }/** * Set lengths using decimal numbers like "10123". */ private void setLengths(String[] strings) throws IOException { if (strings.length != valueCount) { throw invalidLengths(strings); }try { for (int i = 0; i < strings.length; i++) { lengths[i] = Long.parseLong(strings[i]); } } catch (NumberFormatException e) { throw invalidLengths(strings); } }private IOException invalidLengths(String[] strings) throws IOException { throw new IOException("unexpected journal line: " + Arrays.toString(strings)); }public File getCleanFile(int i) { return new File(directory, key + "." + i); }public File getDirtyFile(int i) { return new File(directory, key + "." + i + ".tmp"); } } }

import java.io.InputStream; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.Log; public class BitmapTools {private static final String TAG = "debug"; public static class Size {public Size(int width, int height) { this.width = width; this.height = height; }public void resize(int width, int height) { this.width = width; this.height = height; }public int getWidth() { return width; }public int getHeight() { return height; }@Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; Size size = (Size) o; if (width != size.width) return false; return height == size.height; }@Override public int hashCode() { int result = width; result = 31 * result + height; return result; }@Override public String toString() { return "Size{" + "width=" + width + ", height=" + height + ‘}‘; }private int width; private int height; }public static Bitmap decodeSampledBitmapFromPath(String pathName, int reqWidth, int reqHeight) { // First decode with inJustDecodeBounds=true to check dimensions BitmapFactory.Options opts = new BitmapFactory.Options(); opts.inJustDecodeBounds = true; BitmapFactory.decodeFile(pathName, opts); // Calculate inSampleSize opts.inSampleSize = calculateInSampleSize(opts, reqWidth, reqHeight); // Decode bitmap with inSampleSize set opts.inJustDecodeBounds = false; return BitmapFactory.decodeFile(pathName, opts); }public static Bitmap decodeSampledBitmapFromData(byte[] data, int reqWidth, int reqHeight) { // First decode with inJustDecodeBounds=true to check dimensions BitmapFactory.Options opts = new BitmapFactory.Options(); opts.inJustDecodeBounds = true; BitmapFactory.decodeByteArray(data, 0, data.length, opts); // Calculate inSampleSize opts.inSampleSize = calculateInSampleSize(opts, reqWidth, reqHeight); // Decode bitmap with inSampleSize set opts.inJustDecodeBounds = false; return BitmapFactory.decodeByteArray(data, 0, data.length, opts); }public static Bitmap decodeSampledBitmapFromResource(Resources res, int id, int reqWidth, int reqHeight) { // First decode with inJustDecodeBounds=true to check dimensions BitmapFactory.Options opts = new BitmapFactory.Options(); opts.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, id, opts); // Calculate inSampleSize opts.inSampleSize = calculateInSampleSize(opts, reqWidth, reqHeight); // Decode bitmap with inSampleSize set opts.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, id, opts); }public static Bitmap decodeSampledBitmapFromInputStream(InputStream is, int reqWidth, int reqHeight) { Bitmap bitmap = BitmapFactory.decodeStream(is); if (bitmap == null) return null; // Log.d(TAG, "req size: " + reqWidth + ", " + reqHeight); // Log.d(TAG, "bitmap size: " + bitmap.getWidth() + ", " + bitmap.getHeight()); if (bitmap.getWidth() > reqWidth || bitmap.getHeight() > reqHeight) { Size srcSize = new Size(bitmap.getWidth(), bitmap.getHeight()); Size reqSize = new Size(reqWidth, reqHeight); Size newSize = calculateNewSize(srcSize, reqSize); bitmap = Bitmap.createScaledBitmap(bitmap, newSize.getWidth(), newSize.getHeight(), false); } return bitmap; }public static Size calculateNewSize(Size srcSize, Size reqSize) { int newWidth; int newHeight; if (srcSize.getWidth() > srcSize.getHeight()) { newWidth = reqSize.getWidth(); newHeight = newWidth * srcSize.getHeight() / srcSize.getWidth(); } else { newHeight = reqSize.getHeight(); newWidth = newHeight * srcSize.getWidth() / srcSize.getHeight(); } return new Size(newWidth, newHeight); }public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { final int halfHeight = height / 2; final int halfWidth = width / 2; // Calculate the largest inSampleSize value that is a power of 2 and // keeps both height and width larger than the requested height and // width. while ((halfHeight / inSampleSize) > reqHeight & & (halfWidth / inSampleSize) > reqWidth) { inSampleSize *= 2; } } Log.d(TAG, "inSampleSize=" + inSampleSize); return inSampleSize; } }