Android - how to define ShapeDrawables programmatically?

Question

What I\'m trying to achieve is to use a Drawable with a couple of layers inside it, but control some values at runtime such as the startColor for the gradient. Here\'s what

Answer 1

It seems that is does not work with ShapeDrawable, but take a look at my GradientDrawable example:

GradientDrawable gd = new GradientDrawable(Orientation.BOTTOM_TOP, new int[]{Color.RED, Color.GREEN});
gd.setStroke(10, Color.BLUE);

You may also need following method:

gd.setGradientCenter(float x, float y);
gd.setGradientRadius(float gradientRadius);

Answer 2

Just gonna leave this here... Not tested yet

 /**
 * Created by Nedo on 09.04.2015.
 */
public class ShapeBuilder {

    public static Drawable generateSelectorFromDrawables(Drawable pressed, Drawable normal) {
        StateListDrawable states = new StateListDrawable();
        states.addState(new int[]{ -android.R.attr.state_focused, -android.R.attr.state_pressed, -android.R.attr.state_selected}, normal);
        states.addState(new int[]{ android.R.attr.state_pressed}, pressed);
        states.addState(new int[]{ android.R.attr.state_focused}, pressed);
        states.addState(new int[]{ android.R.attr.state_selected}, pressed);

        return states;
    }

    public static Drawable generateShape(String colorTop, String colorBot, String colorStroke, int stokeSize, float strokeRadius) {
        int top, bot, stroke;
        top = Color.parseColor(colorTop);
        bot = Color.parseColor(colorBot);
        stroke = Color.parseColor(colorStroke);

        GradientDrawable drawable = new GradientDrawable(GradientDrawable.Orientation.BOTTOM_TOP, new int[]{top, bot});
        drawable.setStroke(stokeSize, stroke);
        drawable.setCornerRadius(strokeRadius);

        return drawable;
    }

    public static Drawable buildSelectorShapeFromColors(String colorNormalStroke, String colorNormalBackTop, String colorNormalBackBot,
                                                        String colorPressedStroke, String colorPressedBackTop, String colorPressedBackBot,
                                                        int strokeSize, float strokeRadius) {

        Drawable pressed = generateShape(colorPressedBackTop, colorPressedBackBot, colorPressedStroke, strokeSize, strokeRadius);
        Drawable normal = generateShape(colorNormalBackTop, colorNormalBackBot, colorNormalStroke, strokeSize, strokeRadius);
        return generateSelectorFromDrawables(pressed, normal);
    }
}

Edit: tested Now, had one mistake. You actually have to describe every single state. If you group states they will only be triggered if all of them accure at once...