How to change `solid color` from the code?

Question

I have a Shape defined in xml. Now I need to change a solid color from the code, could you please advice how?

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" android:padding="10dp">
    <solid android:color="#000000"/>
    <corners
        android:bottomRightRadius="8dp"
        android:bottomLeftRadius="8dp"
        android:topLeftRadius="0dp"
        android:topRightRadius="0dp"/>
</shape>

Answer 1

I met the problem when I set the background of the item(in the listview)the shape defined in xml, I've got ClassCastException when I invoke the convertview's getBackground() method, but when I invoke the item's outest view's getBackground() method,the Exception disappear, the problem resolved.

Answer 2

I use this in my code

GradientDrawable myGrad = (GradientDrawable)rectangle.getBackground();
myGrad.setColor(Color.BLACK);

Hope this helps :)

EDIT: for GradientDrawable instead of ShapeDrawable