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
     
       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
      
       (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);            }        }    }}

 

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
     
      (), sThreadFactory);    class LoaderResult {        SoftReference
      
        mImageViewRef;        Bitmap mBitmap;        String mUri;        public LoaderResult(ImageView imageView, String uri, Bitmap bitmap) {            mImageViewRef = new SoftReference
       
        (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. * 
     
       *     
      
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. *     
      
When an entry is being edited, it is not necessary *         to supply data for every value; values default to their previous *         value. * 
     
 * 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
      
        lruEntries            = new LinkedHashMap
       
        (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[] 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 instead        StringBuilder 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
         
          ());    private final Callable
          
            cleanupCallable = new Callable
           
            () { @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
            
              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
             
              (lruEntries.values())) { if (entry.currentEditor != null) { entry.currentEditor.abort(); } } trimToSize(); journalWriter.close(); journalWriter = null; } private void trimToSize() throws IOException { while (size > maxSize) {// Map.Entry
              
                toEvict = lruEntries.eldest(); final Map.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;    }}