Summary

This change makes it easier to extend the RichTextModel.

Problem

Two problems are being solved:

1. A custom model cannot reuse the storage mechanism of the RichTextModel if all it needs is to "overlay" some presentation elements (highlights, for instance) on top of the existing paragraph, since the current API returns an immutable RichParagraph.

2. It is currently impossible for a custom model to iterate over the text segments in a paragraph.

Solution

1. Add a new protected method which allows a custom model to further customize the paragraph presentation before an immutable instance of RichParagraph is build:

protected RichParagraph.Builder prepareParagraph(int index)

2. Add methods to the RichParagraph and RichParagraph.Builder that enable read-only access to the segments:

• getSegmentCount()
• getSegment(int index)

Specification

See the attached API diff file.