Book Image

Cross-Platform Development with Qt 6 and Modern C++

By : Nibedit Dey
Book Image

Cross-Platform Development with Qt 6 and Modern C++

By: Nibedit Dey

Overview of this book

Qt is a cross-platform application development framework widely used for developing applications that can run on a wide range of hardware platforms with little to no change in the underlying codebase. If you have basic knowledge of C++ and want to build desktop or mobile applications with a modern graphical user interface (GUI), Qt is the right choice for you. Cross-Platform Development with Qt 6 and Modern C++ helps you understand why Qt is one of the favorite GUI frameworks adopted by industries worldwide, covering the essentials of programming GUI apps across a multitude of platforms using the standard C++17 and Qt 6 features. Starting with the fundamentals of the Qt framework, including the features offered by Qt Creator, this practical guide will show you how to create classic user interfaces using Qt Widgets and touch-friendly user interfaces using Qt Quick. As you advance, you'll explore the Qt Creator IDE for developing applications for multiple desktops as well as for embedded and mobile platforms. You will also learn advanced concepts about signals and slots. Finally, the book takes you through debugging and testing your app with Qt Creator IDE. By the end of this book, you'll be able to build cross-platform applications with a modern GUI along with the speed and power of native apps.
Table of Contents (17 chapters)
Section 1: The Basics
Section 2: Cross-Platform Development
Section 3: Advanced Programming, Debugging, and Deployment

Understanding signals and the handler event system in QML

Previously, we learned how to connect signals and slots inside C++ source files and use them with the Qt Widgets module. Now, let's look at how we can communicate in QML. QML has a signal and handler mechanism, similar to signals and slots. In a QML document, a signal is an event, and the signal is responded to through a signal handler. Like a slot in C++, a signal handler is invoked when a signal is emitted in QML. In Qt terminology, the method is a slot that is connected to the signal; all the methods defined in QML are created as Qt slots. Hence, there is no separate declaration for slots in QML. A signal is a notification from an object that some event has occurred. You can place logic inside JavaScript or a method to respond to the signal.

Let's look at how to write a signal handler. You can declare a signal handler as follows:

onSignalName : {

Here, signalName is the name of the signal. The...