Android 抽屉布局获得导航视图的方法'；s宽度

我正在寻找方法来确定的宽度，特别是在它被打开之前

这是我当前的实现，它决定了打开时的宽度：

@BindView(R.id.navDrawer) DrawerLayout mNavDrawer;
@BindView(R.id.navigation) NavigationView mNav;

private void setupNavDrawer() {
    mNavDrawer.addDrawerListener(new DrawerLayout.DrawerListener() {
        @Override
        public void onDrawerOpened(View drawerView) {
            final int navWidth = mNav.getWidth();
            // do something
        }
        @Override public void onDrawerSlide(View drawerView, float slideOffset) {}
        @Override public void onDrawerClosed(View drawerView) {}
        @Override public void onDrawerStateChanged(int newState) {}
    });
}