android - Trying to draw a button: how to set a stroke color and how to "align" a gradient to the bottom without knowing the height?

Question

I am creating a button programmatically. It is rounded and has a gradient background, and works fine and looks nice, but I couldn't do two things I wanted:

1. Set a 1 pixel stroke with a given color. I tried getPaint().setStroke(), but couldn't figure how to set the stroke color. How should I do it?
2. Align the gradient to the bottom of the button, no matter what height it has. Is this possible?

For reference, this is the code I'm using:

Button btn = new Button(context);
btn.setPadding(7, 3, 7, 5);
btn.setTextColor(text_color);

// Create a gradient for the button. Height is hardcoded to 30 (I don't know the height beforehand). 
// I wish I could set the gradient aligned to the bottom of the button.
final Shader shader = new LinearGradient(0, 0, 0, 30,
    new int[] { color_1, color_2 },
    null, Shader.TileMode.MIRROR);

float[] roundedCorner = new float[] { 5, 5, 5, 5, 5, 5, 5, 5 }
ShapeDrawable normal = new ShapeDrawable(new RoundRectShape(roundedCorner, null, null));
normal.getPaint().setShader(shader);
normal.setPadding(7, 3, 7, 5);

// Create a state list (I suppressed settings for pressed).
StateListDrawable state_list = new StateListDrawable();
state_list.addState(new int[] { }, normal);

btn.setBackgroundDrawable(state_list);

Answer 1

In terms of your first question, I struggled with this as well, and it doesn't look like there are any suitable methods within Drawables themselves (I was using ShapeDrawable) or the Paint class. However, I was able to extend ShapeDrawable and override the draw method, as below, to give the same result:

public class CustomBorderDrawable extends ShapeDrawable {
    private Paint fillpaint, strokepaint;
    private static final int WIDTH = 3; 

    public CustomBorderDrawable(Shape s) {
        super(s);
        fillpaint = this.getPaint();
        strokepaint = new Paint(fillpaint);
        strokepaint.setStyle(Paint.Style.STROKE);
        strokepaint.setStrokeWidth(WIDTH);
        strokepaint.setARGB(255, 0, 0, 0);
    }

    @Override
    protected void onDraw(Shape shape, Canvas canvas, Paint fillpaint) {
        shape.draw(canvas, fillpaint);
        shape.draw(canvas, strokepaint);
    }

    public void setFillColour(int c){
        fillpaint.setColor(c);
    }
}