how to change the color of the button in main activity?

Hey guys i would like to ask how to change the color of the buttons in the actiity main xml. The button are from the palette of the eclipse and are not image views buttons but the simple ones. here is my code

activity_main.xml:

xmlns:tools="http://ift.tt/LrGmb4"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/default1"
android:orientation="vertical"
tools:context="ca.my.demo.buttondemo.MainActivity" >

<Button

    android:id="@+id/btnDisplayMessage"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:text="Kreatika"
    android:textColor="#ffffff"
    android:textStyle="bold|italic" />

  <Button

      android:id="@+id/btnDisplayMessage1"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentLeft="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentTop="true"
      android:layout_marginTop="63dp"
      android:text="Galaktokomika"
      android:textColor="#ffffff"
      android:textStyle="bold|italic" />

    <Button

        android:id="@+id/btnDisplayMessage2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/btnDisplayMessage1"
        android:layout_marginTop="24dp"
        android:text="Allantika"
        android:textColor="#ffffff"
        android:textStyle="bold|italic" />