session-android/res/layout/fragment_scan_qr_code.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <org.thoughtcrime.securesms.components.camera.CameraView
        android:id="@+id/cameraView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:camera="0" />

    <LinearLayout
        android:id="@+id/overlayView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:weightSum="3" >

        <org.thoughtcrime.securesms.components.ShapeScrim
            android:layout_weight="2"
            android:layout_width="match_parent"
            android:layout_height="0dp"/>

        <TextView
            android:id="@+id/messageTextView"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:padding="@dimen/very_large_spacing"
            android:gravity="center"
            android:text="Scan a user’s QR code to start a session. QR codes can be found by tapping the QR code icon in account settings."
            android:background="?android:windowBackground"
            android:textSize="@dimen/small_font_size"
            android:textColor="?android:textColorTertiary" />

    </LinearLayout>

</FrameLayout>