Chapter 10: Added missing null-check.

Author: Anders Goransson

EatApplication/Eat/src/main/java/com/eat/chapter10/FileDownloadActivity.java

@@ -99,8 +99,9 @@ protected void onProgressUpdate(Bitmap... bitmaps) {
         @Override
         protected void onPostExecute(Void aVoid) {
             super.onPostExecute(aVoid);
-
-            mActivity.mProgressBar.setVisibility(View.GONE);
+            if (mActivity != null) {
+                mActivity.mProgressBar.setVisibility(View.GONE);
+            }
         }
 
         @Override