OpenEUICC/app-common/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/toolbar"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintWidth_percent="1" />

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/main_tabs"
        android:background="?attr/colorSurfaceVariant"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:visibility="gone"
        app:tabTextColor="?attr/colorOnSurfaceVariant"
        app:tabSelectedTextColor="?attr/colorOnSurfaceVariant"
        app:layout_constraintTop_toBottomOf="@id/toolbar"
        app:layout_constraintStart_toStartOf="parent" />

    <ProgressBar
        android:id="@+id/loading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:indeterminate="true"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@id/main_tabs"
        app:layout_constraintBottom_toBottomOf="parent" />

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/view_pager"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/main_tabs"/>

</androidx.constraintlayout.widget.ConstraintLayout>