我有下面的结构和片段replace/add不仅替换了它的主机视图，还替换了整个屏幕。什么会导致这种情况？
无数据的主活动布局

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".activity.MainActivity">

    <FrameLayout
        android:id="@+id/nav_host_fragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="12"
        app:defaultNavHost="true" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_gravity="bottom"
        android:layout_weight="1"
        app:labelVisibilityMode="unlabeled"
        android:background="@drawable/transparent_button"
        app:onNavigationItemSelected="@{viewModel::onNavigationItemSelected}"
        app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior"
        app:menu="@menu/bottom_navigation_menu" />
</LinearLayout>

碎片布局

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="?android:attr/actionBarSize"
    tools:context=".fragment.HomeFragment">

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="20dp"
        android:background="@drawable/transparent_button"
        android:onClick="@{viewModel::onFloatingButtonClicked}"
        android:src="@drawable/ic_baseline_add_24" />
</FrameLayout>

创建时的主要活动

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActivityMainBinding activityMainBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
    mainViewModel = ViewModelProviders.of(this, new ViewModelFactory(getApplication())).get(MainViewModel.class);
    activityMainBinding.setViewModel(mainViewModel);
    activityMainBinding.executePendingBindings();

    fragmentList.put(FragmentsEnum.HOME.getValue(), new HomeFragment());
    fragmentList.put(FragmentsEnum.PROFILE.getValue(), new ProfileFragment());

    Fragments.addFragment(getSupportFragmentManager(), R.id.nav_host_fragment, fragmentList.get(FragmentsEnum.HOME.getValue()), FragmentsEnum.HOME.getValue()); // DEFAULT FRAGMENT
}

碎片利用率

public static void addFragment(FragmentManager manager, int containerId, Fragment fragment, String tag) {
    if (!manager.isStateSaved()) {
        manager.beginTransaction().add(containerId, fragment, tag).commit();
    }
}

在主活动视图上，当活动开始时，我将主片段设置为活动。但它隐藏了我的底部导航栏，取代了整个屏幕。