Excel – Changing color of Bars in a bar chart

Can be achieved by extending the SimpleSeriesRenderer and BarChart classes. Here is my solution for RangeBarChart (all thanks to gilenodm, wish I had some reputation to upvote your answer):

import org.achartengine.renderer.SimpleSeriesRenderer;
public class AdvancedSeriesRenderer extends SimpleSeriesRenderer
{
    private int []  colors;

    public void AdvancedSeriesRenderer ()
    {
    }

    public int getColor ( int position )
    {
        return colors[position];
    }
}

import org.achartengine.chart.RangeBarChart;
import org.achartengine.model.XYMultipleSeriesDataset;
import org.achartengine.renderer.SimpleSeriesRenderer;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;

public class AdvancedRangeBarChart extends RangeBarChart
{
    private int []  barChartColors;

    public AdvancedRangeBarChart ( XYMultipleSeriesDataset dataset, XYMultipleSeriesRenderer renderer, Type type )
    {
        super ( dataset, renderer, type );
    }

    public void setColors ( int [] colorsIn )
    {
        barChartColors = colorsIn;
    }

    @Override
    public void drawSeries ( Canvas canvas, Paint paint, float [] points, SimpleSeriesRenderer seriesRenderer, float yAxisValue, int seriesIndex, int startIndex )
    {
        int seriesNr = mDataset.getSeriesCount ();
        int length = points.length;
        paint.setStyle ( Style.FILL );
        float halfDiffX = getHalfDiffX ( points, length, seriesNr );
        int start = 0;
        if ( startIndex > 0 )
        {
            start = 2;
        }
        for ( int i = start; i < length; i += 4 )
        {
            int colorIndex = (int) ( i / 4 ) % barChartColors.length;
            paint.setColor ( barChartColors[colorIndex] );
            if ( points.length > i + 3 )
            {
                float xMin = points[i];
                float yMin = points[i + 1];
                // xMin = xMax
                float xMax = points[i + 2];
                float yMax = points[i + 3];
                drawBar ( canvas, xMin, yMin, xMax, yMax, halfDiffX, seriesNr, seriesIndex, paint );
            }
        }
    }
}

Jesse's answer is often the cleanest way to do it.

However, it is not accurate that "to have different colored bars they must be on different series" (my emphasis). You can mix and match colors within one series. For example, this makes the second bar of the first series red:

ActiveChart.SeriesCollection(1).Points(2).Interior.Color = RGB(255, 0, 0)

You can use this to do all kinds of neat tricks, such as highlighting bars that exceed some threshold, are associated with leap years, or whatever. You could certainly choose to highlight your average1 and average2 values this way.

If you want to change the color for a point that has a given characteristic, then you have to loop through all points until you find a point that has that characteristic. For example, if you want to color in red the point whose category (XValue) is "avg" then you could do this:

Dim c As Chart
Dim s As Series
Dim iPoint As Long
Dim nPoint As Long

Set c = ActiveChart
Set s = c.SeriesCollection(1)

nPoint = s.Points.Count
For iPoint = 1 To nPoint
    If s.XValues(iPoint) = "avg" Then
        s.Points(iPoint).Interior.Color = RGB(255, 0, 0)
    End If
Next iPoint