增加DiskLruCache，但是这个类没有get和set方法??

ImageLoadHelperByXinYi/src/main/java/bitmap/trainning/google/com/displaybitmapsefficiently/util/core/DiskLruCacheUtil.java

@@ -0,0 +1,115 @@
+package bitmap.trainning.google.com.displaybitmapsefficiently.util.core;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.os.AsyncTask;
+import android.os.Environment;
+
+import java.io.File;
+import java.io.IOException;
+
+import bitmap.trainning.google.com.displaybitmapsefficiently.util.extra.DiskLruCache;
+
+import static android.os.Environment.isExternalStorageRemovable;
+
+/**
+ *DiskLruCacheUtil for bitmap ,save it in disk.
+ * Note :design single instance
+ */
+public class DiskLruCacheUtil {
+    private static DiskLruCacheUtil instance = null;
+    private DiskLruCache mDiskLruCache;
+    private static final Class<DiskLruCacheUtil> mDiskCacheLock = DiskLruCacheUtil.class;
+    private boolean mDiskCacheStarting = true;
+    private static final int DISK_CACHE_SIZE = 1024 * 1024 * 10; // 10MB
+    private static final String DISK_CACHE_SUBDIR = "thumbnails";
+    private Context mContext;
+
+    private  DiskLruCacheUtil(Context context){
+        mContext = context;
+        // Initialize disk cache on background thread
+        File cacheDir = getDiskCacheDir(context, DISK_CACHE_SUBDIR);
+        new InitDiskCacheTask().execute(cacheDir);
+    }
+
+    public static DiskLruCacheUtil getInstance(Context context){
+        if(instance == null){
+            synchronized (mDiskCacheLock)
+            {
+                if(instance == null){
+                    instance = new DiskLruCacheUtil(context);
+                }
+            }
+        }
+        return instance;
+    }
+
+    class InitDiskCacheTask extends AsyncTask<File, Void, Void> {
+        @Override
+        protected Void doInBackground(File... params) {
+            synchronized (mDiskCacheLock) {
+                File cacheDir = params[0];
+                try {
+                    mDiskLruCache = DiskLruCache.open(cacheDir, getAppVersion(mContext),1,DISK_CACHE_SIZE);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+                mDiskCacheStarting = false; // Finished initialization
+                mDiskCacheLock.notifyAll(); // Wake any waiting threads
+            }
+            return null;
+        }
+    }
+
+   /* public void addBitmapToCache(String key, Bitmap bitmap) {
+        // Also add to disk cache
+        synchronized (mDiskCacheLock) {
+            try {
+                if (mDiskLruCache != null && mDiskLruCache.get(key) == null) {
+                    mDiskLruCache.put(key, bitmap);
+                }
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    public Bitmap getBitmapFromDiskCache(String key) {
+        synchronized (mDiskCacheLock) {
+            // Wait while disk cache is started from background thread
+            while (mDiskCacheStarting) {
+                try {
+                    mDiskCacheLock.wait();
+                } catch (InterruptedException e) {}
+            }
+            if (mDiskLruCache != null) {
+                return mDiskLruCache.get(key);
+            }
+        }
+        return null;
+    }*/
+
+    // Creates a unique subdirectory of the designated app cache directory. Tries to use external
+    // but if not mounted, falls back on internal storage.
+    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() ? context.getExternalCacheDir().getPath() :
+                        context.getCacheDir().getPath();
+
+        return new File(cachePath + File.separator + uniqueName);
+    }
+
+    private int getAppVersion(Context context) {
+        try {
+            PackageInfo info = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
+            return info.versionCode;
+        } catch (PackageManager.NameNotFoundException e) {
+            e.printStackTrace();
+        }
+        return 1;
+    }
+}

ImageLoadHelperByXinYi/src/main/java/bitmap/trainning/google/com/displaybitmapsefficiently/util/core/LruCacheUtil.java

@@ -6,10 +6,12 @@
 import android.support.v4.util.LruCache;
 
 /**
- *LruCache for bitmap
+ *LruCache for bitmap,save it in memory.
  * make the class alone,is a nice code style
+ * note:make single instance
  */
 public class LruCacheUtil {
+
     //LruCache for bitmap
     private static LruCache<String, Bitmap> mMemoryCache;
     static {