How to detect if navigation drawer is open?

Assuming you have defined a drawerlayout in xml:

DrawerLayout mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
...
if(mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
  //drawer is open
}

 mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerToggle = new ActionBarDrawerToggle(
            this,                  /* host Activity */
            mDrawerLayout,         /* DrawerLayout object */
            R.drawable.ic_drawer,  /* nav drawer icon to replace 'Up' caret */
            R.string.drawer_open,  /* "open drawer" description */
            R.string.drawer_close  /* "close drawer" description */
            ) {

        /** Called when a drawer has settled in a completely closed state. */
        public void onDrawerClosed(View view) {
            super.onDrawerClosed(view);
            getActionBar().setTitle(mTitle);
        }

        /** Called when a drawer has settled in a completely open state. */
        public void onDrawerOpened(View drawerView) {
            super.onDrawerOpened(drawerView);
            getActionBar().setTitle(mDrawerTitle);
        }
    };

    // Set the drawer toggle as the DrawerListener
    mDrawerLayout.setDrawerListener(mDrawerToggle);

That listener use:)

Use:

mDrawerLayout.isDrawerOpen() method

Example:

    if(mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
        mDrawerLayout.closeDrawer(Gravity.LEFT); //CLOSE Nav Drawer!
    }else{
        mDrawerLayout.openDrawer(Gravity.LEFT); //OPEN Nav Drawer!
    }