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 | public class ImageCache {
private static final String TAG = "ImageCache";
 
// Default memory cache size in kilobytes
private static final int DEFAULT_MEM_CACHE_SIZE = 1024 * 5; // 5MB
 
// Default disk cache size in bytes
private static final int DEFAULT_DISK_CACHE_SIZE = 1024 * 1024 * 10; // 10MB
 
// 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;
private static final int DISK_CACHE_INDEX = 0;
 
// 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_INIT_DISK_CACHE_ON_CREATE = false;
 
private DiskLruCache mDiskLruCache;
private LruCache<String, BitmapDrawable> mMemoryCache;
public static ImageCacheParams mCacheParams;
private final Object mDiskCacheLock = new Object();
private boolean mDiskCacheStarting = true;
 
private Set<SoftReference<Bitmap>> mReusableBitmaps;
 
/**
 * Create a new ImageCache object using the specified parameters. This should not be
 * called directly by other classes, instead use
 * {@link ImageCache#getInstance(FragmentManager, ImageCacheParams)} to fetch an ImageCache
 * instance.
 *
 * @param cacheParams The cache parameters to use to initialize the cache
 */
public ImageCache(ImageCacheParams cacheParams) {
 
    init(cacheParams);
}
 
/**
 * Return an {@link ImageCache} instance. A {@link RetainFragment} is used to retain the
 * ImageCache object across configuration changes such as a change in device orientation.
 *
 * @param fragmentManager The fragment manager to use when dealing with the retained fragment.
 * @param cacheParams The cache parameters to use if the ImageCache needs instantiation.
 * @return An existing retained ImageCache object or a new one if one did not exist
 */
public static ImageCache getInstance(
        FragmentManager fragmentManager, ImageCacheParams cacheParams) {
 
    // Search for, or create an instance of the non-UI RetainFragment
    final RetainFragment mRetainFragment = findOrCreateRetainFragment(fragmentManager);
 
    // See if we already have an ImageCache stored in RetainFragment
    ImageCache imageCache = (ImageCache) mRetainFragment.getObject();
 
    // No existing ImageCache, create one and store it in RetainFragment
    if (imageCache == null) {
        imageCache = new ImageCache(cacheParams);
        mRetainFragment.setObject(imageCache);
    }
 
    return imageCache;
}
 
/**
 * Initialize the cache, providing all parameters.
 *
 * @param cacheParams The cache parameters to initialize the cache
 */
public void init(ImageCacheParams cacheParams) {
    mCacheParams = cacheParams;
 
    //BEGIN_INCLUDE(init_memory_cache)
    // Set up memory cache
    if (mCacheParams.memoryCacheEnabled) {
        if (BuildConfig.DEBUG) {
            Log.d(TAG, "Memory cache created (size = " + mCacheParams.memCacheSize + ")");
        }
 
        // If we're running on Honeycomb or newer, create a set of reusable bitmaps that can be
        // populated into the inBitmap field of BitmapFactory.Options. Note that the set is
        // of SoftReferences which will actually not be very effective due to the garbage
        // collector being aggressive clearing Soft/WeakReferences. A better approach
        // would be to use a strongly references bitmaps, however this would require some
        // balancing of memory usage between this set and the bitmap LruCache. It would also
        // require knowledge of the expected size of the bitmaps. From Honeycomb to JellyBean
        // the size would need to be precise, from KitKat onward the size would just need to
        // be the upper bound (due to changes in how inBitmap can re-use bitmaps).
        if (Utils.hasHoneycomb()) {
            mReusableBitmaps =
                    Collections.synchronizedSet(new HashSet<SoftReference<Bitmap>>());
        }
 
        mMemoryCache = new LruCache<String, BitmapDrawable>(mCacheParams.memCacheSize) {
 
            /**
             * Notify the removed entry that is no longer being cached
             */
            @Override
            protected void entryRemoved(boolean evicted, String key,
                    BitmapDrawable oldValue, BitmapDrawable newValue) {
                if (RecyclingBitmapDrawable.class.isInstance(oldValue)) {
                    // The removed entry is a recycling drawable, so notify it
                    // that it has been removed from the memory cache
                    ((RecyclingBitmapDrawable) oldValue).setIsCached(false);
                } else {
                    // The removed entry is a standard BitmapDrawable
 
                    if (Utils.hasHoneycomb()) {
                        // We're running on Honeycomb or later, so add the bitmap
                        // to a SoftReference set for possible use with inBitmap later
                        mReusableBitmaps.add(new SoftReference<Bitmap>(oldValue.getBitmap()));
                    }
                }
            }
 
            /**
             * Measure item size in kilobytes rather than units which is more practical
             * for a bitmap cache
             */
            @Override
            protected int sizeOf(String key, BitmapDrawable value) {
                final int bitmapSize = getBitmapSize(value) / 1024;
                return bitmapSize == 0 ? 1 : bitmapSize;
            }
        };
    }
    //END_INCLUDE(init_memory_cache)
 
    // By default the disk cache is not initialized here as it should be initialized
    // on a separate thread due to disk access.
    if (cacheParams.initDiskCacheOnCreate) {
        // Set up disk cache
        initDiskCache();
    }
}
 
/**
 * Initializes the disk cache.  Note that this includes disk access so this should not be
 * executed on the main/UI thread. By default an ImageCache does not initialize the disk
 * cache when it is created, instead you should call initDiskCache() to initialize it on a
 * background thread.
 */
public void initDiskCache() {
    // Set up disk cache
    synchronized (mDiskCacheLock) {
        if (mDiskLruCache == null || mDiskLruCache.isClosed()) {
            File diskCacheDir = mCacheParams.diskCacheDir;
            if (mCacheParams.diskCacheEnabled && diskCacheDir != null) {
                if (!diskCacheDir.exists()) {
                    diskCacheDir.mkdirs();
                }
                if (getUsableSpace(diskCacheDir) > mCacheParams.diskCacheSize) {
                    try {
                        mDiskLruCache = DiskLruCache.open(
                                diskCacheDir, 1, 1, mCacheParams.diskCacheSize);
                        if (BuildConfig.DEBUG) {
                            Log.d(TAG, "Disk cache initialized");
                        }
                    } catch (final IOException e) {
                        mCacheParams.diskCacheDir = null;
                        Log.e(TAG, "initDiskCache - " + e);
                    }
                }
            }
        }
        mDiskCacheStarting = false;
        mDiskCacheLock.notifyAll();
    }
}
 
 
public void addBitmapToCache(String data, BitmapDrawable value) {
    //BEGIN_INCLUDE(add_bitmap_to_cache)
    if (data == null || value == null) {
        return;
    }
 
    // Add to memory cache
    if (mMemoryCache != null) {
        if (RecyclingBitmapDrawable.class.isInstance(value)) {
            // The removed entry is a recycling drawable, so notify it
            // that it has been added into the memory cache
            ((RecyclingBitmapDrawable) value).setIsCached(true);
        }
        mMemoryCache.put(data, value);
    }
 
    synchronized (mDiskCacheLock) {
        // Add to disk cache
        if (mDiskLruCache != null) {
            final String key = hashKeyForDisk(data);
            OutputStream out = null;
            try {
                DiskLruCache.Snapshot snapshot = mDiskLruCache.get(key);
                if (snapshot == null) {
                    final DiskLruCache.Editor editor = mDiskLruCache.edit(key);
                    if (editor != null) {
                        out = editor.newOutputStream(DISK_CACHE_INDEX);
                        value.getBitmap().compress(
                                mCacheParams.compressFormat, mCacheParams.compressQuality, out);
                        editor.commit();
                        out.close();
                    }
                } else {
                    snapshot.getInputStream(DISK_CACHE_INDEX).close();
                }
            } catch (final IOException e) {
                Log.e(TAG, "addBitmapToCache - " + e);
            } catch (Exception e) {
                Log.e(TAG, "addBitmapToCache - " + e);
            } finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                } catch (IOException e) {}
            }
        }
    }
    //END_INCLUDE(add_bitmap_to_cache)
}
 
 
public BitmapDrawable getBitmapFromMemCache(String data) {
    //BEGIN_INCLUDE(get_bitmap_from_mem_cache)
    BitmapDrawable memValue = null;
 
    if (mMemoryCache != null) {
        memValue = mMemoryCache.get(data);
    }
 
    if (BuildConfig.DEBUG && memValue != null) {
        Log.d(TAG, "Memory cache hit");
    }
 
    return memValue;
    //END_INCLUDE(get_bitmap_from_mem_cache)
}
 
 
public Bitmap getBitmapFromDiskCache(String data) {
    //BEGIN_INCLUDE(get_bitmap_from_disk_cache)
    final String key = hashKeyForDisk(data);
    Bitmap bitmap = null;
 
    synchronized (mDiskCacheLock) {
        while (mDiskCacheStarting) {
            try {
                mDiskCacheLock.wait();
            } catch (InterruptedException e) {}
        }
        if (mDiskLruCache != null) {
            InputStream inputStream = null;
            try {
                final DiskLruCache.Snapshot snapshot = mDiskLruCache.get(key);
                if (snapshot != null) {
                    if (BuildConfig.DEBUG) {
                        Log.d(TAG, "Disk cache hit");
                    }
                    inputStream = snapshot.getInputStream(DISK_CACHE_INDEX);
                    if (inputStream != null) {
                        FileDescriptor fd = ((FileInputStream) inputStream).getFD();
 
                        // Decode bitmap, but we don't want to sample so give
                        // MAX_VALUE as the target dimensions
                        bitmap = ImageResizer.decodeSampledBitmapFromDescriptor(
                                fd, Integer.MAX_VALUE, Integer.MAX_VALUE, this);
                    }
                }
            } catch (final IOException e) {
                Log.e(TAG, "getBitmapFromDiskCache - " + e);
            } finally {
                try {
                    if (inputStream != null) {
                        inputStream.close();
                    }
                } catch (IOException e) {}
            }
        }
        return bitmap;
    }
    //END_INCLUDE(get_bitmap_from_disk_cache)
}
 
/**
 * @param options - BitmapFactory.Options with out* options populated
 * @return Bitmap that case be used for inBitmap
 */
protected Bitmap getBitmapFromReusableSet(BitmapFactory.Options options) {
    //BEGIN_INCLUDE(get_bitmap_from_reusable_set)
    Bitmap bitmap = null;
 
    if (mReusableBitmaps != null && !mReusableBitmaps.isEmpty()) {
        synchronized (mReusableBitmaps) {
            final Iterator<SoftReference<Bitmap>> iterator = mReusableBitmaps.iterator();
            Bitmap item;
 
            while (iterator.hasNext()) {
                item = iterator.next().get();
 
                if (null != item && item.isMutable()) {
                    // Check to see it the item can be used for inBitmap
                    if (canUseForInBitmap(item, options)) {
                        bitmap = item;
 
                        // Remove from reusable set so it can't be used again
                        iterator.remove();
                        break;
                    }
                } else {
                    // Remove from the set if the reference has been cleared.
                    iterator.remove();
                }
            }
        }
    }
 
    return bitmap;
    //END_INCLUDE(get_bitmap_from_reusable_set)
}
 
/**
 * Clears both the memory and disk cache associated with this ImageCache object. Note that
 * this includes disk access so this should not be executed on the main/UI thread.
 */
public void clearCache() {
    if (mMemoryCache != null) {
        mMemoryCache.evictAll();
        if (BuildConfig.DEBUG) {
            Log.d(TAG, "Memory cache cleared");
        }
    }
 
    synchronized (mDiskCacheLock) {
        mDiskCacheStarting = true;
        if (mDiskLruCache != null && !mDiskLruCache.isClosed()) {
            try {
                mDiskLruCache.delete();
                if (BuildConfig.DEBUG) {
                    Log.d(TAG, "Disk cache cleared");
                }
            } catch (IOException e) {
                Log.e(TAG, "clearCache - " + e);
            }
            mDiskLruCache = null;
            initDiskCache();
        }
    }
}
 
/**
 * Flushes the disk cache associated with this ImageCache object. Note that this includes
 * disk access so this should not be executed on the main/UI thread.
 */
public void flush() {
    synchronized (mDiskCacheLock) {
        if (mDiskLruCache != null) {
            try {
                mDiskLruCache.flush();
                if (BuildConfig.DEBUG) {
                    Log.d(TAG, "Disk cache flushed");
                }
            } catch (IOException e) {
                Log.e(TAG, "flush - " + e);
            }
        }
    }
}
 
/**
 * Closes the disk cache associated with this ImageCache object. Note that this includes
 * disk access so this should not be executed on the main/UI thread.
 */
public void close() {
    synchronized (mDiskCacheLock) {
        if (mDiskLruCache != null) {
            try {
                if (!mDiskLruCache.isClosed()) {
                    mDiskLruCache.close();
                    mDiskLruCache = null;
                    if (BuildConfig.DEBUG) {
                        Log.d(TAG, "Disk cache closed");
                    }
                }
            } catch (IOException e) {
                Log.e(TAG, "close - " + e);
            }
        }
    }
}
 
/**
 * A holder class that contains cache parameters.
 */
public static class ImageCacheParams {
    public int memCacheSize = DEFAULT_MEM_CACHE_SIZE;
    public int diskCacheSize = DEFAULT_DISK_CACHE_SIZE;
    public File diskCacheDir;
    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 initDiskCacheOnCreate = DEFAULT_INIT_DISK_CACHE_ON_CREATE;
 
    /**
     * Create a set of image cache parameters that can be provided to
     * {@link ImageCache#getInstance(FragmentManager, ImageCacheParams)} or
     * {@link ImageWorker#addImageCache(FragmentManager, ImageCacheParams)}.
     * @param context A context to use.
     * @param diskCacheDirectoryName A unique subdirectory name that will be appended to the
     *                               application cache directory. Usually "cache" or "images"
     *                               is sufficient.
     */
    public ImageCacheParams(Context context, String diskCacheDirectoryName) {
        diskCacheDir = getDiskCacheDir(context, diskCacheDirectoryName);
    }
 
    /**
     * Sets the memory cache size based on a percentage of the max available VM memory.
     * Eg. setting percent to 0.2 would set the memory cache to one fifth of the available
     * memory. Throws {@link IllegalArgumentException} if percent is < 0.01 or > .8.
     * memCacheSize is stored in kilobytes instead of bytes as this will eventually be passed
     * to construct a LruCache which takes an int in its constructor.
     *
     * This value should be chosen carefully based on a number of factors
     * Refer to the corresponding Android Training class for more discussion:
     * http://developer.android.com/training/displaying-bitmaps/
     *
     * @param percent Percent of available app memory to use to size memory cache
     */
    public void setMemCacheSizePercent(float percent) {
        if (percent < 0.01f || percent > 0.8f) {
            throw new IllegalArgumentException("setMemCacheSizePercent - percent must be "
                    + "between 0.01 and 0.8 (inclusive)");
        }
        memCacheSize = Math.round(percent * Runtime.getRuntime().maxMemory() / 1024);
    }
}
 
/**
 * @param candidate - Bitmap to check
 * @param targetOptions - Options that have the out* value populated
 * @return true if <code>candidate</code> can be used for inBitmap re-use with
 *      <code>targetOptions</code>
 */
@TargetApi(VERSION_CODES.KITKAT)
private static boolean canUseForInBitmap(
        Bitmap candidate, BitmapFactory.Options targetOptions) {
    //BEGIN_INCLUDE(can_use_for_inbitmap)
    if (!Utils.hasKitKat()) {
        // On earlier versions, the dimensions must match exactly and the inSampleSize must be 1
        return candidate.getWidth() == targetOptions.outWidth
                && candidate.getHeight() == targetOptions.outHeight
                && targetOptions.inSampleSize == 1;
    }
 
    // From Android 4.4 (KitKat) onward we can re-use if the byte size of the new bitmap
    // is smaller than the reusable bitmap candidate allocation byte count.
    int width = targetOptions.outWidth / targetOptions.inSampleSize;
    int height = targetOptions.outHeight / targetOptions.inSampleSize;
    int byteCount = width * height * getBytesPerPixel(candidate.getConfig());
    return byteCount <= candidate.getAllocationByteCount();
    //END_INCLUDE(can_use_for_inbitmap)
}
 
/**
 * Return the byte usage per pixel of a bitmap based on its configuration.
 * @param config The bitmap configuration.
 * @return The byte usage per pixel.
 */
private static int getBytesPerPixel(Config config) {
    if (config == Config.ARGB_8888) {
        return 4;
    } else if (config == Config.RGB_565) {
        return 2;
    } else if (config == Config.ARGB_4444) {
        return 2;
    } else if (config == Config.ALPHA_8) {
        return 1;
    }
    return 1;
}
 
/**
 * Get a usable cache directory (external if available, internal otherwise).
 *
 * @param context The context to use
 * @param uniqueName A unique directory name to append to the cache dir
 * @return The cache dir
 */
public static File getDiskCacheDir(Context context, String uniqueName) {
    // Check if media is mounted or storage is built-in, if so, try and use external cache dir
    // otherwise use internal cache dir
    final String cachePath =
            Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) ||
                    !isExternalStorageRemovable() ? getExternalCacheDir(context).getPath() :
                            context.getCacheDir().getPath();
 
    return new File(cachePath + File.separator + uniqueName);
}
 
/**
 * A hashing method that changes a string (like a URL) into a hash suitable for using as a
 * disk filename.
 */
public static String hashKeyForDisk(String key) {
    String cacheKey;
    try {
        final MessageDigest mDigest = MessageDigest.getInstance("MD5");
        mDigest.update(key.getBytes());
        cacheKey = bytesToHexString(mDigest.digest());
    } catch (NoSuchAlgorithmException e) {
        cacheKey = String.valueOf(key.hashCode());
    }
    return cacheKey;
}
 
private static String bytesToHexString(byte[] bytes) {
    // http://stackoverflow.com/questions/332079
    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();
}
 
/**
 * Get the size in bytes of a bitmap in a BitmapDrawable. Note that from Android 4.4 (KitKat)
 * onward this returns the allocated memory size of the bitmap which can be larger than the
 * actual bitmap data byte count (in the case it was re-used).
 *
 * @param value
 * @return size in bytes
 */
@TargetApi(VERSION_CODES.KITKAT)
public static int getBitmapSize(BitmapDrawable value) {
    Bitmap bitmap = value.getBitmap();
 
    // From KitKat onward use getAllocationByteCount() as allocated bytes can potentially be
    // larger than bitmap byte count.
    if (Utils.hasKitKat()) {
        return bitmap.getAllocationByteCount();
    }
 
    if (Utils.hasHoneycombMR1()) {
        return bitmap.getByteCount();
    }
 
    // Pre HC-MR1
    return bitmap.getRowBytes() * bitmap.getHeight();
}
 
/**
 * Check if external storage is built-in or removable.
 *
 * @return True if external storage is removable (like an SD card), false
 *         otherwise.
 */
@TargetApi(VERSION_CODES.GINGERBREAD)
public static boolean isExternalStorageRemovable() {
    if (Utils.hasGingerbread()) {
        return Environment.isExternalStorageRemovable();
    }
    return true;
}
 
/**
 * Get the external app cache directory.
 *
 * @param context The context to use
 * @return The external cache dir
 */
@TargetApi(VERSION_CODES.FROYO)
public static File getExternalCacheDir(Context context) {
    if (Utils.hasFroyo()) {
        return context.getExternalCacheDir();
    }
 
    // Before Froyo we need to construct the external cache dir ourselves
    final String cacheDir = "/Android/data/" + context.getPackageName() + "/cache/";
    return new File(Environment.getExternalStorageDirectory().getPath() + cacheDir);
}
 
/**
 * Check how much usable space is available at a given path.
 *
 * @param path The path to check
 * @return The space available in bytes
 */
@TargetApi(VERSION_CODES.GINGERBREAD)
public static long getUsableSpace(File path) {
    if (Utils.hasGingerbread()) {
        return path.getUsableSpace();
    }
    final StatFs stats = new StatFs(path.getPath());
    return (long) stats.getBlockSize() * (long) stats.getAvailableBlocks();
}
 
/**
 * Locate an existing instance of this Fragment or if not found, create and
 * add it using FragmentManager.
 *
 * @param fm The FragmentManager manager to use.
 * @return The existing instance of the Fragment or the new instance if just
 *         created.
 */
private static RetainFragment findOrCreateRetainFragment(FragmentManager fm) {
    //BEGIN_INCLUDE(find_create_retain_fragment)
    // Check to see if we have retained the worker fragment.
    RetainFragment mRetainFragment = (RetainFragment) fm.findFragmentByTag(TAG);
 
    // If not retained (or first time running), we need to create and add it.
    if (mRetainFragment == null) {
        mRetainFragment = new RetainFragment();
        fm.beginTransaction().add(mRetainFragment, TAG).commitAllowingStateLoss();
    }
 
    return mRetainFragment;
    //END_INCLUDE(find_create_retain_fragment)
}
 
/**
 * A simple non-UI Fragment that stores a single Object and is retained over configuration
 * changes. It will be used to retain the ImageCache object.
 */
public static class RetainFragment extends Fragment {
    private Object mObject;
 
    /**
     * Empty constructor as per the Fragment documentation
     */
    public RetainFragment() {}
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
 
        // Make sure this Fragment is retained over a configuration change
        setRetainInstance(true);
    }
 
    /**
     * Store a single object in this Fragment.
     *
     * @param object The object to store
     */
    public void setObject(Object object) {
        mObject = object;
    }
 
    /**
     * Get the stored object.
     *
     * @return The stored object
     */
    public Object getObject() {
        return mObject;
    }
} | 
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