Horizontal LinearGradient with android

I haven’t done much android coding, but one approach worth trying is:

int x1 = 0, y1 = 0, x2 = 0,  y2 = 40;

The x never changes in the gradient only the y does.

So what this might look like is:

Shader shader = new LinearGradient(0, 0, 0, 40, Color.WHITE, Color.BLACK, TileMode.CLAMP);
Paint paint = new Paint(); 
paint.setShader(shader); 
canvas.drawRect(new RectF(0, 0, 100, 40), paint);