How to Create Android Transparent Background Color

transparent_button.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="#000000" >

    <Button
        android:id="@+id/transparantButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="creatorb"
        android:background="#00ffffff"
        android:textColor="#FFFFFF"
        android:textStyle="bold" />

</LinearLayout>