Apply an alpha gradient

I'm using this

    public void drawSky(Canvas canvas) {

    float lineY =(CamOverlayTest.camViewCenterY/2)+3*(Math.max(0,(-90 - CamOverlayTest.swRoll)));

    int[] gColor = {Color.BLUE,Color.BLACK};

    GradientDrawable gradient = new GradientDrawable(GradientDrawable.Orientation.BOTTOM_TOP,gColor );
    gradient.setGradientType(GradientDrawable.LINEAR_GRADIENT);
    // gradient.setDither(true);
    Rect bounds = new Rect();
    bounds.set(CamOverlayTest.camViewCenterX-120开发者_如何学运维, 0, CamOverlayTest.camViewCenterX+120, (int)lineY-2);
    gradient.setBounds(bounds);
    gradient.draw(canvas);
    }

to draw a blue sky turning to black but I'd like it to also have an alpha gradient as well but my brain can't work out how to do it.

I basically want the gradient to start off transparent and then become fully opaque as well as changing from blue to black

Any ideas please :)

Simon

Try replacing this line:

int[] gColor = {0x000000FF,0xff000000};

The first two digits of each color represent alpha.

You may have to set a pixel format like so:

getWindow().setFormat(PixelFormat.RGBA_8888);