app/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:id="@+id/main_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="visible"
tools:context=".activities.MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
android:theme="@style/Theme.CampusCapture"
app:layout_constraintTop_toTopOf="parent"
app:popupTheme="@style/Theme.CampusCapture"
tools:layout_editor_absoluteX="0dp" />
<androidx.fragment.app.FragmentContainerView
android:id="@+id/fragmentContainerViewMain"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/toolbar"
tools:ignore="MissingConstraints" />
</androidx.constraintlayout.widget.ConstraintLayout>