Like all other primary chart and graph classes in Androidplot, PieChart is simply a composition of widgets along with convenience methods. The real work is actually done by PieWidget.

Pie charts are composed of one or more values called Segments which combines a vaue and a label:

Segment segment = new Segment("my segment", 10);

Displaying a Segment to a pie chart also requires a SegmentFormatter. SegmentFormatter is what defines the visual characteristics of the associated segment; color, border thickness, segment offset, label text style (if any) etc. The below code instantiates a new SegmentFormatter with a segment color of red:

SegmentFormatter formatter = new SegmentFormatter(Color.RED);

Finally, the Segment must be added to the pie chart along with it's SegmentFormatter:

pie.addSegment(segment, formatter);

As mentioned above, SegmentFormatter defines how a Segment is visually represented in a PieChart. In addition to basic color / border line styling params, there are several parameters available to visually distinguish a segment:

Value in pixels used to "shift" the position of the segment relative to the center of the PieChart. The visual effect is equivalent to cutting up a pie and dragging one piece outward, away from the rest of the pie.

Value in degrees used to shrink the radial edges of the segment inward. The visual effect is equivalent to shaving the edges off of a slice of pie, resulting in a narrower slice of pie.

Value in pixels used to shrink the inner section of the pie. The visual effect is equivalent to cutting the tip off of a slice of pie.

Value in pixels used to shrink the outer edge of the pie. The visual effect is equivalent to evenly shaving the crust off of a slice of pie.

See the DemoApp's pie chart example source for a comprehensive usage example.