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)

Saving your logs to a file

Developers commonly need to have logs. In some situations, you will not have access to the console output, or you will have to study the application state afterwards. In both cases, the log has to be output to a file.

Qt provides a practical way of redirecting your logs (qDebug, qInfo, qWarning, and so on) to any device that is convenient for you: QtMessageHandler. To use it, you have to register a function that will save the logs to the desired output.

For example, in your main.cpp, add the following function:

#include <QFile> 
#include <QTextStream> 
void messageHander(QtMsgType type,  
                   const QMessageLogContext& context,  
                   const QString& message) { 
    QString levelText; 
    switch (type) { 
        case QtDebugMsg: 
            levelText = "Debug";