Android and Arduino Mega ADK simple LED Blink

activity_main.xml

<RelativeLayout 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" tools:context=".MainActivity">

    <ToggleButton
        android:text="@string/ToggleButton"
        android:id="@+id/toggleButtonLED"
        android:layout_width="200dp"
        android:layout_height="150dp"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:textSize="50sp"
        android:onClick="blinkLED" />

    <TextView
        android:id="@+id/connectionStatus"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/toggleButtonLED"
        android:layout_alignLeft="@+id/toggleButtonLED" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/toggleButtonLED"
        android:layout_alignRight="@+id/toggleButtonLED" />

</RelativeLayout>