[library] Fix saving files when on a device without external storage.

The reason was that createTempFile defaults to the
 external storage. I've now added a new Builder constructor
 which takes a Context. We now use getCacheDir as the
 dir for temp files.

library/src/uk/co/senab/bitmapcache/BitmapLruCache.java

@@ -18,6 +18,7 @@
 
 import com.jakewharton.DiskLruCache;
 
+import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.os.AsyncTask;
@@ -121,11 +122,19 @@ private static String transformUrlForDiskCacheKey(String url) {
         return Md5.encode(url);
     }
 
-    private DiskLruCache mDiskCache;
+    private File mTempDir;
 
-    private final BitmapMemoryLruCache mMemoryCache;
+    /**
+     * Memory Cache Variables
+     */
+    private BitmapMemoryLruCache mMemoryCache;
 
-    private final RecyclePolicy mRecyclePolicy;
+    private RecyclePolicy mRecyclePolicy;
+
+    /**
+     * Disk Cache Variables
+     */
+    private DiskLruCache mDiskCache;
 
     // Variables which are only used when the Disk Cache is enabled
     private HashMap<String, ReentrantLock> mDiskCacheEditLocks;
@@ -137,9 +146,10 @@ private static String transformUrlForDiskCacheKey(String url) {
     // Transient
     private ScheduledFuture<?> mDiskCacheFuture;
 
-    protected BitmapLruCache(BitmapMemoryLruCache memoryCache, RecyclePolicy recyclePolicy) {
-        mMemoryCache = memoryCache;
-        mRecyclePolicy = recyclePolicy;
+    BitmapLruCache(Context context) {
+        if (null != context) {
+            mTempDir = context.getCacheDir();
+        }
     }
 
     /**
@@ -369,7 +379,7 @@ public CacheableBitmapDrawable put(final String url, final InputStream inputStre
         // can be read multiple times
         File tmpFile = null;
         try {
-            tmpFile = File.createTempFile("bitmapcache_", null);
+            tmpFile = File.createTempFile("bitmapcache_", null, mTempDir);
 
             // Pipe InputStream to file
             Util.copy(inputStream, tmpFile);
@@ -464,6 +474,11 @@ synchronized void setDiskCache(DiskLruCache diskCache) {
         }
     }
 
+    void setMemoryCache(BitmapMemoryLruCache memoryCache, RecyclePolicy recyclePolicy) {
+        mMemoryCache = memoryCache;
+        mRecyclePolicy = recyclePolicy;
+    }
+
     private ReentrantLock getLockForDiskCacheEdit(String url) {
         synchronized (mDiskCacheEditLocks) {
             ReentrantLock lock = mDiskCacheEditLocks.get(url);
@@ -524,6 +539,8 @@ private static long getHeapSize() {
             return Runtime.getRuntime().maxMemory();
         }
 
+        private Context mContext;
+
         private boolean mDiskCacheEnabled;
 
         private File mDiskCacheLocation;
@@ -536,7 +553,17 @@ private static long getHeapSize() {
 
         private RecyclePolicy mRecyclePolicy;
 
+        /**
+         * @deprecated You should now use {@link Builder(Context)}. This is so that we can reliably
+         * find a write-able location for temporary files.
+         */
         public Builder() {
+            this(null);
+        }
+
+        public Builder(Context context) {
+            mContext = context;
+
             // Disk Cache is disabled by default, but it's default size is set
             mDiskCacheMaxSize = DEFAULT_DISK_CACHE_MAX_SIZE_MB * MEGABYTE;
 
@@ -551,17 +578,15 @@ public Builder() {
          *         builder.
          */
         public BitmapLruCache build() {
-            BitmapMemoryLruCache memoryCache = null;
+            final BitmapLruCache cache = new BitmapLruCache(mContext);
 
             if (isValidOptionsForMemoryCache()) {
                 if (Constants.DEBUG) {
                     Log.d("BitmapLruCache.Builder", "Creating Memory Cache");
                 }
-                memoryCache = new BitmapMemoryLruCache(mMemoryCacheMaxSize);
+                cache.setMemoryCache(new BitmapMemoryLruCache(mMemoryCacheMaxSize), mRecyclePolicy);
             }
 
-            final BitmapLruCache cache = new BitmapLruCache(memoryCache, mRecyclePolicy);
-
             if (isValidOptionsForDiskCache()) {
                 new AsyncTask<Void, Void, DiskLruCache>() {
 

sample/src/uk/co/senab/bitmapcache/samples/SampleApplication.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  ******************************************************************************/
+
 package uk.co.senab.bitmapcache.samples;
 
 import android.app.Application;
@@ -43,7 +44,7 @@ public void onCreate() {
         }
         cacheLocation.mkdirs();
 
-        BitmapLruCache.Builder builder = new BitmapLruCache.Builder();
+        BitmapLruCache.Builder builder = new BitmapLruCache.Builder(this);
         builder.setMemoryCacheEnabled(true).setMemoryCacheMaxSizeUsingHeapSize();
         builder.setDiskCacheEnabled(true).setDiskCacheLocation(cacheLocation);