android-calculatorpp/app/src/main/res/layout/activity_empty.xml

<?xml version="1.0" encoding="utf-8"?>

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  ~ Copyright 2013 serso aka se.solovyev
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  ~ Licensed under the Apache License, Version 2.0 (the "License");
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  ~ You may obtain a copy of the License at
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  ~    http://www.apache.org/licenses/LICENSE-2.0
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<LinearLayout
    android:id="@+id/main"
    style="@style/CppMain"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_height="?actionBarSize"
        android:layout_width="match_parent" />
</LinearLayout>