activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    tools:context=".MainActivity">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">
        <androidx.appcompat.widget.Toolbar
            android:id="@+id/main_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />
    </com.google.android.material.appbar.AppBarLayout>
    <Button
        android:id="@+id/button_disable_report"
        android:layout_width="wrap_content"
        android:layout_height="44dp"
        android:layout_margin="8dp"
        android:background="@drawable/button"
        android:onClick="previewDisabledUsersReport"
        android:padding="8dp"
        android:text="@string/disabled_users_report"
        android:textAllCaps="false"
        style="?android:buttonBarButtonStyle"
        android:textColor="@android:color/white"
        android:textSize="14sp" />


    <com.github.barteksc.pdfviewer.PDFView
        android:id="@+id/payment_pdf_viewer"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
    />

</LinearLayout>