[CMFileManager] Fix the DrawerLayout don't disapper after press back key.

Procedures
1.Go into filemanager and enter a directory(such as Music).
2.Open the menu Button in the top left corner and popup the drawerlayout.
3.press the back key.

The DrawerLayout don't disapper and the navigation view back to the next higher level.

Change-Id: I13c78491e2be767e7611d57c2c513013d96465eb
(cherry picked from commit 34f4d1c880bd78482f6fa9dfc701692b8504ffd6)

1 files changed, 4 insertions, 0 deletions

diff --git a/src/com/cyanogenmod/filemanager/activities/NavigationActivity.java b/src/com/cyanogenmod/filemanager/activities/NavigationActivity.java
index e052cfe1..a3af6b56 100644
--- a/src/com/cyanogenmod/filemanager/activities/NavigationActivity.java
+++ b/src/com/cyanogenmod/filemanager/activities/NavigationActivity.java
@@ -1727,6 +1727,10 @@ public class NavigationActivity extends Activity
 
     @Override
     public void onBackPressed() {
+        if (mDrawerLayout.isDrawerOpen(Gravity.START)) {
+            mDrawerLayout.closeDrawer(Gravity.START);
+            return;
+        }
         if (checkBackAction()) {
             performHideEasyMode();
             return;