activity_main.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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <com.mercadopago.views.MPButton
        android:layout_width="match_parent"
        android:layout_height="@dimen/mpsdk_button_height"
        android:layout_marginTop="25dp"
        android:gravity="center"
        android:text="Pagar $100"
        android:onClick="submit"
        style="@style/mpsdk_button_normal"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/mp_results"
        android:paddingTop="50dp"/>
</LinearLayout>