如何让我的片段与另一个片段全屏显示，因为它是父片段而不是活动片段？

<FrameLayout
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

ChildFragment childFragment = new ChildFragment();
FragmentManager fragmentManager = getChildFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.fragment_container, childFragment);
transaction.commit();

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!-- 子片段的内容 -->

</LinearLayout>