drawing random circles

gistfile1.java

    private int lastColor = Color.BLACK;
    private final Random random = new Random();
    private final Paint paint = new Paint();
    private final int radius = 230;
    private final Handler handler = new Handler();

    private final Runnable updateCircle = new Runnable() {
        @Override public void run() {
            lastColor = random.nextInt(2) == 1 ? Color.RED : Color.GREEN;
            paint.setColor(lastColor);
            invalidate();
            handler.postDelayed(this, 1000);
        }
    };

    @Override protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        handler.post(updateCircle);
    }

    @Override protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        handler.removeCallbacks(updateCircle);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // your other stuff here
        canvas.drawCircle(random.nextInt(canvas.getWidth()-radius/2) + radius/2f, random.nextInt(canvas.getHeight()-radius/2) + radius/2f, radius, paint);
    }