openEndDrawer method

void openEndDrawer ()

Opens the end side Drawer (if any).

If the scaffold has a non-null Scaffold.endDrawer, this function will cause the end side drawer to begin its entrance animation.

Normally this is not needed since the Scaffold automatically shows an appropriate IconButton, and handles the edge-swipe gesture, to show the drawer.

To close the end side drawer once it is open, use Navigator.pop.

See Scaffold.of for information about how to obtain the ScaffoldState.

Implementation 

void openEndDrawer() {
  if (_drawerKey.currentState != null && _drawerOpened)
    _drawerKey.currentState.close();
  _endDrawerKey.currentState?.open();
}