Book Image

Getting Started with Qt 5

By : Benjamin Baka
Book Image

Getting Started with Qt 5

By: Benjamin Baka

Overview of this book

Qt is a cross-platform application framework and widget toolkit that is used to create GUI applications that can run on different hardware and operating systems. The main aim of this book is to introduce Qt to the reader. Through the use of simple examples, we will walk you through building blocks without focusing too much on theory. Qt is a popular tool that can be used for building a variety of applications, such as web browsers, media players such as VLC, and Adobe Photoshop. Following Qt installation and setup, the book dives straight into helping you create your first application. You will be introduced to Widgets, Qt's interface building block, and the many varieties that are available for creating GUIs. Next, Qt's core concept of signals and slots are well illustrated with sufficient examples. The book further teaches you how to create custom widgets, signals and slots, and how to communicate useful information via dialog boxes. To cap everything off, you will be taken through writing applications that can connect to databases in order to persist data. By the end of the book, you should be well equipped to start creating your own Qt applications and confident enough to pick up more advanced Qt techniques and materials to hone your skills.
Table of Contents (8 chapters)

Event handlers

All QObjects have an event() method that receives events. For QWidgets, this method will relay the event object to more specific event handlers. It is possible to redefine what an event handler should do by sub-classing the widget of interest and re-implementing that event handler.

Let's create an application where we shall re-implement an event handler.

Create a folder containing the main.cpp, mainwindow.cpp, and mainwindow.h files. The mainwindow.h file should contain the following code:

#include <QMainWindow>
#include <QMoveEvent>
#include <QMainWindow>
class MainWindow: public QMainWindow {
MainWindow(QWidget *parent = 0);
void moveEvent(QMoveEvent *event);

In the preceding code, we have only sub-classed QMainWindow. A default constructor is declared and the event handler that we want to override...