Android : EditText background base line color changing based on its focus in android

I need to design EditText with base line showed in below image and it will be change to some other color when it receives focus.!

i am using the following.

 <EditText    
    android:id="@+id/mobilenumber" 
    android:drawableLeft="@drawable/mobile"
    android:drawablePadding="15dp" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:inputType="number"
    android:background="@drawable/edt_bg"
    android:singleLine="true"
    android:textColorHint="#FFFFFF"
    android:hint="@string/mobilenumber"
    android:layout_marginTop="20dp"
    android:layout_gravity="center"
    android:padding="5dp"
    android:imeOptions="actionNext"
    android:maxLength="10"
    android:textColor="#ffffff"
    android:textCursorDrawable="@null"

    />

So, please guide me how to handle this.