I need to change the stroke color to a user defined color. Nothing to do with the state

1. If you have drawable file for a “view” like this

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >

<corners android:radius="5dp" />

<solid android:color="@android:color/white" />

<stroke
    android:width="3px"
    android:color="@color/blue" />

</shape>

Then you can change

a. Stroke color :

GradientDrawable drawable = (GradientDrawable)view.getBackground();
drawable.mutate(); // only change this instance of the xml, not all components using this xml
drawable.setStroke(3, Color.RED); // set stroke width and stroke color 

b. Solid color :

GradientDrawable drawable = (GradientDrawable)view.getBackground();
drawable.setColor(Color.RED); // set solid color

2. If you have drawable file for a “view” like this

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_checked="true" android:id="@+id/buttonSelected">
        <shape>
            <solid android:color="@color/blue" />
            <stroke android:width="1px" android:color="@color/blue" />
        </shape>
    </item>
    <item android:state_checked="false" android:id="@+id/buttonNotSelected">
        <shape android:shape="rectangle">
            <solid android:color="@color/white" />
            <stroke android:width="1px" android:color="@color/blue" />
        </shape>
    </item>
</selector>

Then you can change the individual item attributes by taking separate drawable objects by there positions.

StateListDrawable drawable = (StateListDrawable)view.getBackground();
DrawableContainerState dcs = (DrawableContainerState)drawable.getConstantState();
Drawable[] drawableItems = dcs.getChildren();
GradientDrawable gradientDrawableChecked = (GradientDrawable)drawableItems[0]; // item 1 
GradientDrawable gradientDrawableUnChecked = (GradientDrawable)drawableItems[1]; // item 2

now to change stroke or solid color :

//solid color
gradientDrawableChecked.setColor(Color.BLUE);
gradientDrawableUnChecked.setColor(Color.RED);

//stroke
gradientDrawableChecked.setStroke(1, Color.RED);
gradientDrawableUnChecked.setStroke(1, Color.BLUE);