Add a new row and place it there.
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#A9F5E1"
android:orientation="vertical">
<TableRow android:padding="5dp"
android:paddingBottom="10dp">
<ImageButton android:layout_height="150dp"
android:layout_width="400dp"
android:src="@drawable/flood_sign"
android:background="@android:color/transparent"
android:id="@+id/enterPreventiva"/>
</TableRow>
<TableRow android:padding="5dp"
android:paddingBottom="10dp">
<TextView android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:text="@string/preventiva"
android:textColor="#FFFFFF"/>
</TableRow>
</TableLayout>