Fix rotation of transaction lists causes crash of application

Fixes #664

Author: codinguser

app/src/main/java/org/gnucash/android/ui/transaction/TransactionsActivity.java

@@ -143,8 +143,10 @@ public void onItemSelected(AdapterView<?> parent, View view, int position, long
                     mTabLayout.addTab(mTabLayout.newTab().setText(R.string.section_header_transactions));
                 }
             }
-            // Hide the favorite icon of the selected account to avoid clutter
-            ((TextView) view).setCompoundDrawablesWithIntrinsicBounds(0,0,0,0);
+            if (view != null) {
+                // Hide the favorite icon of the selected account to avoid clutter
+                ((TextView) view).setCompoundDrawablesWithIntrinsicBounds(0, 0, 0, 0);
+            }
             //refresh any fragments in the tab with the new account UID
             refresh();
         }