Android: How can i put an image as a point style in a line graph?

Question

I am plotting line graph using achart in which I need to put an image instead of a point style. How can i do that? Please help me?

protected void setRenderer(XYMultipleSeriesRenderer renderer, int[] colors, PointStyle[] styles) {
    renderer.setAxisTitleTextSize(16);
    renderer.setChartTitleTextSize(20);
    renderer.setLabelsTextSize(15);
    renderer.setLegendTextSize(15);
    renderer.setPointSize(5f);
    renderer.setMargins(new int[] { 20, 30, 15, 20 });
    int length = colors.length;
    for (int i = 0; i < length; i++) {
      XYSeriesRenderer r = new XYSeriesRenderer();
      r.setColor(colors[i]);

// I need to use image instead of styles here

r.setPointStyle(styles[i]);
  renderer.addSeriesRenderer(r);
}

}