private int getSign() {
            int[] sign = new int[]{-1, 1};
            return sign[Math.round((float) Math.random())];
        }
To animate values you have to change targets values and then call {@link Chart#startDataAnimation()}
method(don't confuse with View.animate()).
hellocharts-samples/src/lecho/lib/hellocharts/samples/BubbleChartActivity.java