Book Image

Mastering Qt 5 - Second Edition

By : Guillaume Lazar, Robin Penea
Book Image

Mastering Qt 5 - Second Edition

By: Guillaume Lazar, Robin Penea

Overview of this book

Qt 5.11 is an app development framework that provides a great user experience and develops full capability applications with Qt Widgets, QML, and even Qt 3D. Whether you're building GUI prototypes or fully-fledged cross-platform GUI applications with a native look and feel, Mastering Qt 5 is your fastest, easiest, and most powerful solution. This book addresses various challenges and teaches you to successfully develop cross-platform applications using the Qt framework, with the help of well-organized projects. Working through this book, you will gain a better understanding of the Qt framework, as well as the tools required to resolve serious issues, such as linking, debugging, and multithreading. You'll start off your journey by discovering the new Qt 5.11 features, soon followed by exploring different platforms and learning to tame them. In addition to this, you'll interact with a gamepad using Qt Gamepad. Each chapter is a logical step for you to complete in order to master Qt. By the end of this book, you'll have created an application that has been tested and is ready to be shipped.
Table of Contents (16 chapters)

Beneath Q_OBJECT and signals/slots

The Qt building system should be clearer now. Still, the Q_OBJECT macro and the signal/slot/emit keywords are still black boxes. Let's dive into Q_OBJECT. You can Ctrl + click on the macro name, or select it and press F2 to go to its declaration.

The truth lies in the source code; Q_OBJECT is defined in the qobjectdefs.h file (in Qt 5.7):

#define Q_OBJECT \ 
public: \ 
    // skipped details 
    static const QMetaObject staticMetaObject; \ 
    virtual const QMetaObject *metaObject() const; \ 
    virtual void *qt_metacast(const char *); \ 
    virtual int qt_metacall(QMetaObject::Call, int, void **); \ 
private: \ 
    // skipped details  
qt_static_metacall(QObject *, QMetaObject::Call, int, void **); 

This macro defines some static functions and static QMetaObject. The body of these static functions is implemented...