Chapter 13. Models and Views

Chapter 13. Models and Views
	Part I. Design Patterns and Qt

Table of Contents

13.1. Model-View-Controller (MVC)

13.2. Qt Models and Views

13.2.1. QFileSystemModel
13.2.2. Multiple Views
13.2.3. Delegate Classes

13.3. Table Models

13.3.1. Standard or Abstract?
13.3.2. Editable Models
13.3.3. Sorting and Filtering

13.4. Tree Models

13.4.1. Trolltech Model Testing Tool

13.5. Smarter Pointers

13.6. Exercises: Models and Views

13.7. Review Questions

[ fromfile: modelview.xml id: modelview ]

Abstract

A Model-View design framework provides tools and techniques for separating the set of underlying data classes (the model) from the set of classes that present the user with a GUI (the view). Models typically organize the data, which can be tabular, or hiearchical. In this chapter, we will show how to use the model classes in Qt to represent many different kinds of data.

A Model class represents data.
A View class presents a user interface for the data.
Some good reasons for maintaining model/view separation:

reduces the complexity of each.
makes it possible to maintain several different, but consistent, views of the same data.

Most GUI toolkits offer list, table, and tree view classes, but require the developer to store data inside them.
Qt has Widget classes derived from corresponding View classes, as shown in Figure 13.1.
Storing data inside widgets leads to a strong dependency between UI and data representation.
It also makes it difficult to maintain multiple consistent views of the same data.

Figure 13.1. Widgets and Views


12.9. Review Questions		13.1. Model-View-Controller (MVC)