BouncingBalls.java 文件源码

private ShapeHolder addBall(float x, float y) {
    OvalShape circle = new OvalShape();
    circle.resize(50f, 50f);
    ShapeDrawable drawable = new ShapeDrawable(circle);
    ShapeHolder shapeHolder = new ShapeHolder(drawable);
    shapeHolder.setX(x - 25f);
    shapeHolder.setY(y - 25f);
    int red = (int)(Math.random() * 255);
    int green = (int)(Math.random() * 255);
    int blue = (int)(Math.random() * 255);
    int color = 0xff000000 | red << 16 | green << 8 | blue;
    Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
    int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
    RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
            50f, color, darkColor, Shader.TileMode.CLAMP);
    paint.setShader(gradient);
    shapeHolder.setPaint(paint);
    balls.add(shapeHolder);
    return shapeHolder;
}