navController.addOnDestinationChangedListener { _, destination, _ ->
   if(destination.id == R.id.full_screen_destination) {
       
       bottomNavigationView.visibility = View.GONE
   } else {
       
       bottomNavigationView.visibility = View.VISIBLE
   }
}

在主Activity中执行此操作。这里R.id.full_screen_destination是导航片段中片段的id。

若要从片段中访问BottomNavigationView，请使用以下代码：

BottomNavigationView navBar = getActivity().findViewById(R.id.bottomBar);

因为fragment总是在Activity中，所以你可以在fragment中调用getActivity()来访问Activity中已经存在的对象。

活动

public class MainActivity extends Activity {
//...
   Toolbar toolbar;
//...
   public Toolbar getNav() {
      return toolbar;
   }
//...
}

片段

//...
if(getActivity() != null && getActivity instanceOf MainActivity)
    ((MainActivity)getActivity()).getNav().setVisiblity(View.GONE);
//...

试试这个，
在Xml格式的BottomNavigationView中添加此行
应用程序：layout_behavior="@字符串/滚动时隐藏底部视图行为”
并使用CoOrdinator Layout实现此BottomNavigation行为，您可以使用滚动侦听器隐藏或显示视图。

public class BottomNavigationViewBehavior extends CoordinatorLayout.Behavior<BottomNavigationView> {

private int height;

@Override
public boolean onLayoutChild(CoordinatorLayout parent, BottomNavigationView child, int layoutDirection) {
    height = child.getHeight();
    return super.onLayoutChild(parent, child, layoutDirection);
}

@Override
public boolean onStartNestedScroll(@NonNull CoordinatorLayout coordinatorLayout,
                               BottomNavigationView child, @NonNull 
                               View directTargetChild, @NonNull View target,
                               int axes, int type)
{
    return axes == ViewCompat.SCROLL_AXIS_VERTICAL;
}

@Override
public void onNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull BottomNavigationView child,
           @NonNull View target, int dxConsumed, int dyConsumed,
           int dxUnconsumed, int dyUnconsumed, 
            @ViewCompat.NestedScrollType int type)
{
   if (dyConsumed > 0) {
       slideDown(child);
   } else if (dyConsumed < 0) {
       slideUp(child);
   }
}

private void slideUp(BottomNavigationView child) {
    child.clearAnimation();
    child.animate().translationY(0).setDuration(200);
}

private void slideDown(BottomNavigationView child) {
    child.clearAnimation();
    child.animate().translationY(height).setDuration(200);
}

}
将此行代码添加到包含底部导航Activity中

bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_nav);
CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) 
bottomNavigationView .getLayoutParams();
layoutParams.setBehavior(new BottomNavigationViewBehavior());

试试这个，让我知道Digvijay。编码快乐。

Fragment有onAttach()方法，它给予上下文。因此，您必须使用以下方法创建Activity的示例：

MainActivity mainActivity;
@Override
public void onAttach(Context context) {
    super.onAttach(context);
    mainActivity = (MainActivity)context;
}

现在，使用boolean参数创建方法，该参数隐藏和显示底部条。

public void visibilityOfBottom(boolean isScroll){
  if(isScroll){

  // hide bottom bar

  } else{
   // show bottom bar
  }

}

现在使用MainActivity上下文访问片段中上述方法，方法为：

mainActivity.visibilityOfBottom(false);

Kotlin
从片段访问导航视图

val navBar: BottomNavigationView = activity!!.findViewById(R.id.bottomBar)

我发现在V6中隐藏底部导航器的唯一方法是这样做-

Stack Nav {
   Bottom Nav
   Screen 1
   Screen 2
   Screen 3
}

将此代码添加到您的片段。将隐藏底部导航。

AppCompatActivity activity = (AppCompatActivity) view.getContext();
    chipNavigationBar = activity.findViewById(R.id.chipNavigation);
    chipNavigationBar.animate().translationY(chipNavigationBar.getHeight()).setDuration(1000);

使用此代码：当向下滚动到你的片段时，回收视图将隐藏底部导航。然后当向上滚动时，它将显示底部导航。

private View view;
private AppCompatActivity activity;
private ChipNavigationBar chipNavigationBar;
//...............................................

@Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        if (view == null) {
            view = inflater.inflate(R.layout.list_fragment, container, false);
         hide_NavigationBar_adwhen_Scrolling();
        }
        return view;
    }

//...........................................................

private void hide_NavigationBar_adwhen_Scrolling() {
        activity = (AppCompatActivity) view.getContext();
        chipNavigationBar = activity.findViewById(R.id.chipNavigation);

        RecyclerView recyclerView = view.findViewById(R.id.recylerView);
       recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            if (dy > 0) {//on_Scrolled_down
                //  chipNavigationBar.animate().translationY(200).setDuration(500);
               chipNavigationBar.animate().translationY(banner_ad_card_1.getHeight()).setDuration(1000);

            } else {//on_Scrolled_up
                 chipNavigationBar.setVisibility(View.VISIBLE);
                chipNavigationBar.animate().translationY(0).setDuration(1000);
                //  chipNavigationBar.setItemSelected(R.id.home, true);
            }
        }

        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
        }
    });
    }

新增

app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior"

至
底部导航视图

app:layout_behavior="@string/appbar_scrolling_view_behavior"

至
循环检视