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.

Preface

Who this book is for

What this book covers

To get the most out of this book

Free Chapter

Get Your Qt Feet Wet

Get Your Qt Feet Wet

Qt project basic structure

MainWindow structure

Qt Designer interface

Signals and slots

Using a QDialog

Distributing code responsibility

Emitting a custom signal using lambdas

Simplifying with the auto type and a range-based for loop

Discovering qmake Secrets

Discovering qmake Secrets

Designing a cross-platform project

Transforming SysInfo into a singleton

Exploring Qt Charts

CpuWidget using QCharts

Memory using Qcharts

The .pro file in depth

Under the hood of qmake

Beneath Q_OBJECT and signals/slots

Dividing Your Project and Ruling Your Code

Dividing Your Project and Ruling Your Code

Designing a maintainable project

Defining data classes

Storing your data in a database

Protecting your code with a smart pointer

Implementing the model

Conquering the Desktop UI

Conquering the Desktop UI

Creating a GUI linked to a core shared library

Listing your albums with AlbumListWidget

Creating ThumbnailProxyModel

Displaying the selected album with AlbumWidget

Enhancing thumbnails with PictureDelegate

Displaying a picture with PictureWidget

Composing your Gallery app

Dominating the Mobile UI

Dominating the Mobile UI

Starting with Qt Quick and QML

Checking your development environment

Creating a Qt Quick project

Preparing your Qt Quick gallery entry point

Displaying albums with ListView

Theming the application with a QML singleton

Loading a database on mobile devices

Creating a new album from a custom InputDialog

Loading images with an ImageProvider

Displaying thumbnails in GridView

Swiping through full resolution images

Even Qt Deserves a Slice of Raspberry Pi

Even Qt Deserves a Slice of Raspberry Pi

Discovering Qt3D

Configuring Qt for your Raspberry Pi

Creating an entry point for your Qt3D code

Setting up the scene

Assembling your Qt3D entities

Preparing the board game

Crafting entities from the factory

Building a snake engine in JavaScript

Varying the HUD with QML states

Profiling your QML application

Third-Party Libraries without a Headache

Third-Party Libraries without a Headache

Creating your Qt Designer plugin

Configuring the project for Windows

Configuring the project for Linux

Configuring the project for Mac

Implementing your OpenCV filters

Designing the UI with FilterWidget

Exposing your plugin to Qt Designer

Using your Qt Designer plugin

Building the image-filter application

Animations - Its Alive, Alive!

Animations - Its Alive, Alive!

Creating an SDK using the Qt Plugin system

Creating your plugins

Loading your plugins dynamically

Using the plugins inside the application

Discovering the Animation Framework

Making your thumbnails jump

Fading in the picture

Flashing the thumbnail in a sequence

Keeping Your Sanity with Multithreading

Keeping Your Sanity with Multithreading

Discovering QThread

Flying over Qt multithreading technologies

Architecting the Mandelbrot project

Defining a Job class with QRunnable

Using QThreadPool in MandelbrotCalculator

Displaying the fractal with MandelbrotWidget

Need IPC? Get Your Minions to Work

Need IPC? Get Your Minions to Work

Inter-process communication techniques

Architecturing an IPC project

Laying down the foundations with an SDK

Working with QDataStream and QTcpSocket

Interacting with sockets in the worker

Interacting with sockets from the application

Building your own QTcpServer

Having Fun with Multimedia and Serialization

Having Fun with Multimedia and Serialization

Architecting the drum machine project

Creating a drum track

Making your objects serializable with QVariant

Serializing objects in JSON format

Serializing objects in XML format

Serializing objects in binary format

Playing low-latency sounds with QSoundEffect

Triggering a QButton with your keyboard

Bringing PlaybackWorker to life

Accepting mouse drag-and-drop events

You Shall (Not) Pass with QTest

You Shall (Not) Pass with QTest

Discovering Qt Test

Executing your tests

Writing factorized tests with datasets

Benchmarking your code

Testing your GUI

Spying on your application with QSignalSpy

All Packed and Ready to Deploy

All Packed and Ready to Deploy

Packaging your application

Packaging for Windows

Packaging for Linux with a distribution package

Packaging for Linux with AppImage

Packaging for OS X

Packaging for Android

Packaging for iOS

Qt Hat Tips and Tricks

Qt Hat Tips and Tricks

Managing your workspace with sessions

Searching with the Locator

Increasing the compilation speed

Examining memory with Qt Creator

Generating random numbers

Silencing unused variable warnings

Logging custom objects to QDebug

Improving log messages

Saving your logs to a file

Generating a command-line interface

Sending and receiving HTTP data

Playing with Qt Gamepad

Styling QML with Qt Quick Controls 2

Other Books You May Enjoy

Other Books You May Enjoy

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Creating your Qt Designer plugin

In Chapter 4, Conquering the Desktop UI, we created a custom Qt widget in Qt Designer using the promoting technique. It is now time to learn how to create a custom Qt widget by building a plugin for Qt Designer. Your widget will be available from the Design mode in the Widget Box, alongside other regular Qt widgets. For this project example, we will create a FilterWidget class that processes an input image to apply a filter. The widget will also display the filter name and a dynamic thumbnail of the filtered picture.

This project is composed of two subprojects:

filter-plugin-designer: This is a Qt Designer plugin containing the FilterWidget class and the image-processing code. This plugin is a dynamic library that will be used by the Qt Creator to offer our new FilterWidget in the Form Editor.
image-filter: This is a Qt widget application using...