Drawer Layout not closing on back pressed (depending on support-v4 lib)

I have the exactly same problem after upgrading the support library to 20.0.0.

Add below one line code can fix my problem. (onCreate in my activitiy)

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);

    mDrawerLayout = (DrawerLayout) this.findViewById(R.id.drawer_layout);
    mDrawerLayout.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); /* add this line */

    ....
}

Here is a quick fix to your problem. Just override the onBackPressed() method in your Activity / Fragment :

@Override
public void onBackPressed()
{
    if (mDrawerLayout.isDrawerOpen(Gravity.START))
        mDrawerLayout.closeDrawer(Gravity.START);
    else
        super.onBackPressed();
}

Use Gravity.START for the left drawer, Gravity.END for the right one

The solution with mDrawerLayout.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); is not recommend because you can't gain focus if you have a TextEdit on the activity. Better use the onBackPressed() solution as it mentioned before.

@Override
public void onBackPressed()
{
  if (mDrawerLayout.isOpen())
    mDrawerLayout.close();
  else
    super.onBackPressed();
}

In setUpNavDrawer

mDrawerLayout.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);

Also

@Override
public void onBackPressed()
{
  if (mDrawerLayout.isOpen())
    mDrawerLayout.close();
  else
    super.onBackPressed();
}