Как поместить фрагмент поверх activity

В спиннере есть список, по клику на строку выводится фрагмент, но выводится на активити, нужно сделать чтобы эту активи перекрывал фрагментом полностью. В какую сторону мне нужно копать?

main.activity

public class MainActivity extends AppCompatActivity {

Spinner spinner1, spinner2;
FragmentOne fragmentOne;
FragmentTwo fragmentTwo;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    {

        VideoView videoPlayer;
        videoPlayer = findViewById(R.id.videoView3);
        Uri myVideoUri = Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.video);
        videoPlayer.setVideoURI(myVideoUri);
        MediaController mediaController = new MediaController(this);
        videoPlayer.setMediaController(mediaController);
        mediaController.setMediaPlayer(videoPlayer);


    }
    fragmentOne = new FragmentOne();
    fragmentTwo= new FragmentTwo();

    spinner1 = findViewById(R.id.spinner1);
    String selected = spinner1.getSelectedItem().toString();
    Toast.makeText(getApplicationContext(), selected, Toast.LENGTH_SHORT).show();

    ArrayAdapter<String> adapter = new ArrayAdapter<>(
            MainActivity.this, R.layout.custom_spinner, getResources().getStringArray(R.array.List)

    );
    adapter.setDropDownViewResource(R.layout.customs_spinner_dropdown);
    spinner1.setAdapter(adapter);


    spinner2 = findViewById(R.id.spinner2);
    String selected1 = spinner2.getSelectedItem().toString();
    Toast.makeText(getApplicationContext(), selected1, Toast.LENGTH_SHORT).show();

    ArrayAdapter<String> adapter1 = new ArrayAdapter<>(
            MainActivity.this, R.layout.custom_spinner, getResources().getStringArray(R.array.ListTwo)
    );
    adapter1.setDropDownViewResource(R.layout.customs_spinner_dropdown);
    spinner2.setAdapter(adapter1);

    spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
            switch (i) {
                case 0:
                    selectFragment (fragmentOne);
                    break;
                case 1:
                    selectFragment (fragmentTwo);
                    break;
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {

        }
    });
}

private void selectFragment(Fragment fragment) {
    FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
    fragmentTransaction.replace(R.id.FrameLayout,fragment);
    fragmentTransaction.commit();
}


}

ActivityMain.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"

android:scrollbarAlwaysDrawHorizontalTrack="true"
android:scrollbarAlwaysDrawVerticalTrack="true"
android:scrollbars="vertical"
tools:context=".MainActivity">


<RelativeLayout
    android:id="@+id/Relative1"
    android:layout_width="match_parent"
    android:layout_height="235dp">


    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_alignParentEnd="true"
        android:layout_alignParentBottom="true"
        android:layout_marginEnd="-2dp"
        android:layout_marginBottom="0dp"
        android:contentDescription="@string/todo"
        app:srcCompat="@drawable/big" />

</RelativeLayout>

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

<TableLayout
    android:id="@+id/TableLayout"
    android:layout_width="match_parent"
    android:layout_height="95dp"
    android:layout_below="@id/Relative1"
    android:layout_alignParentStart="true"
    android:layout_marginStart="0dp"
    android:layout_marginTop="0dp"
    android:layout_marginBottom="0dp"
    android:background="#1dbf48">

    <TableRow

        android:id="@+id/first_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#1dbf48">


        <Button
            android:id="@+id/button13"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/Glav"
            android:textAlignment="center" />


        <Button
            android:id="@+id/button24"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/Fhoto"
            android:textAlignment="center" />

        <Button
            android:id="@+id/button16"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/Info"
            android:textAlignment="center" />

        <Button
            android:id="@+id/button14"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/Contacts"
            android:textAlignment="center" />


    </TableRow>

    <TableRow


        android:id="@+id/second_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="1dp"
        android:background="#1dbf48">

        <Button
            android:id="@+id/button23"
            android:layout_width="wrap_content"
            android:layout_height="50dp"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/News"
            android:textAlignment="center" />

        <Spinner
            android:id="@+id/spinner1"
            android:layout_width="125dp"
            android:layout_height="48dp"
            android:background="@drawable/bg_setting"
            android:entries="@array/List"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:spinnerMode="dropdown"
            android:textAlignment="center" />

        <Spinner
            android:id="@+id/spinner2"
            android:layout_width="109dp"
            android:layout_height="48dp"
            android:background="@drawable/bg_setting"
            android:entries="@array/ListTwo"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:spinnerMode="dropdown"
            android:textAlignment="center" />


        <Button
            android:id="@+id/button22"
            android:layout_width="wrap_content"
            android:layout_height="50dp"
            android:background="@drawable/bg_setting"
            android:fontFamily="@font/montserrat_bold"
            android:inputType="textCapWords"
            android:text="@string/Me"
            android:textAlignment="center" />

    </TableRow>

</TableLayout>


<VideoView
    android:id="@+id/videoView3"
    android:layout_width="match_parent"
    android:layout_height="328dp"
    android:layout_below="@+id/Relative1"
    android:layout_alignParentStart="true"
    android:layout_alignParentEnd="true"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginStart="0dp"
    android:layout_marginTop="95dp"
    android:layout_marginEnd="0dp"
    android:layout_marginBottom="0dp" />