udacity_my_app_portfolio_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        style="@style/AppPortfolioTitleStyle"
        android:text="@string/portfolio_title"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button"
        style="@style/AppPortfolioButtonStyle"
        android:text="@string/spotify_streamer"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button2"
        style="@style/AppPortfolioButtonStyle"
        android:text="@string/scores_app"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button3"
        style="@style/AppPortfolioButtonStyle"
        android:text="@string/library_app"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button4"
        style="@style/AppPortfolioButtonStyle"
        android:text="@string/build_it_bigger"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button5"
        style="@style/AppPortfolioButtonStyle"
        android:text="@string/xyz_reader"
        android:layout_gravity="center_horizontal" />

    <Button
        android:id="@+id/button6"
        style="@style/AppPortfolioButtonStyle.SelectedButtonStyle"
        android:text="@string/capstone"
        android:layout_gravity="center_horizontal" />

</LinearLayout>