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- Herausgeber: Packt Publishing
- Kategorie: Fachliteratur
- Sprache: Englisch
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.
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Seitenzahl: 563
Veröffentlichungsjahr: 2018
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Mastering Qt 5 Second Edition
Copyright © 2018 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing or its dealers and distributors, will be held liable for any damages caused or alleged to have been caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
Commissioning Editor:Kunal ChaudhariAcquisition Editor:Larissa PintoContent Development Editor:Flavian VazTechnical Editor:Akhil NairCopy Editor:Safis EditingProject Coordinator:Devanshi DoshiProofreader:Safis EditingIndexer:Rekha NairGraphics:Jason MonteiroProduction Coordinator:Shraddha Falebhai
First published: December 2016 Second edition: August 2018
Production reference: 1230818
Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK.
ISBN 978-1-78899-539-9
www.packtpub.com
To my sisters, Christine and Patricia. To my parents, Béatrice and Claude. To my fiancé, Sophie.
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Contributors
About the authors
Guillaume Lazaris a software engineer living in France, near Paris. He has worked in different companies, from start-ups to multinationals, for the last 10 years. He took the opportunity to observe and learn many team organizations and technologies.
In 2014, he founded his own software development company at the age of 27. The current hierarchical organization that applies to most companies seems obsolete to him. With his own company, he wants to try a different approach.
Although he defines himself as a Qt framework lover, he likes to mix different technologies and platforms. He also spends time on game development, machine learning, and electronics, because "things" become "alive".
Robin Peneahas been working in the software industry for a more than a decade. He worked in start-ups and large companies with many technologies that ranged from embedded software to web development. Armed with this experience, he wrote the Mastering Qt 5 book to spread what he loves the most about the programming craft: proper design and quality code. The teaching bug has bitten him, and he continues to share what he learned online using videos. When he is not tinkering with some new technology, he is either on a wall, rock-climbing, or playing music on his piano. You can reach him via Twitter @synapticrob.
About the reviewers
Pavel Strakhov is a software architect and developer from Russia. He started working with Qt in 2011 in Moscow Institute of Physics and Technology, where it was used to build scientific image processing software. He was highly active in the Qt section of StackOverflow, helping people learn Qt and solve issues. He also worked on Qt bindings for Rust. He is the main author of the book called Game Programming Using Qt 5 / Beginner's Guide / Second Edition published in 2018 by Packt.
Kévin Lemaire is a software engineer since 2011. He lives in the north of Paris since he was born. He first studied accountancy but has quickly been interested in how softwares were makes it easier and switched to IT studies. Now he gets to work in a full Microsoft environment: C++, C#, and WPF. He also is a MCP for SQL Server 2012.
Kévin works for Arc Informatique, a French SCADA provider. He is in charge of data consistency, which starts with the acquisition of industrial equipments, to its storage in files or databases, and data enhancement with reporting.
Kévin has always been fond of Japan. Firstly through anime, then to its music, which he spends time translating as a hobby. He is a dog person and adopted a lovely Shiba Inu.
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Table of Contents
Title Page
Copyright and Credits
Mastering Qt 5 Second Edition
Dedication
Packt Upsell
Why subscribe?
PacktPub.com
Contributors
About the authors
About the reviewers
Packt is searching for authors like you
Preface
Who this book is for
What this book covers
To get the most out of this book
Download the example code files
Conventions used
Get in touch
Reviews
Get Your Qt Feet Wet
Qt project basic structure
MainWindow structure
Qt Designer interface
Signals and slots
Custom QWidget
Adding a task
Using a QDialog
Distributing code responsibility
Emitting a custom signal using lambdas
Simplifying with the auto type and a range-based for loop
Summary
Discovering qmake Secrets
Designing a cross-platform project
Adding the Windows implementation
Adding the Linux implementation
Adding the macOS implementation
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
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
Summary
Other Books You May Enjoy
Leave a review - let other readers know what you think
Preface
C++ is a powerful language. Coupled with Qt, you have in your hands a cross-platform framework that allies performance and ease of use. Qt is a vast framework that provides tools in many areas (GUI, threads, networking, and so on). 25 years after its inception, Qt continues to evolve and grow with each release.
This book aims to teach you how to squeeze the best out of Qt 5.11 with the new C++14 additions (lambdas, smart pointers, enum classes, and so on). These two technologies together bring you a safe and powerful development toolbox. Throughout the book, we try to emphasize a clean architecture that lets you create and maintain your application in a complex environment.
Each chapter is based on an example project that is the basis of all the discussion. Here are some tasters about what we will see in this book:
Uncover qmake secrets
Take a deep dive in
the model/view architecture and study how you can build a
complex application with this pattern
Study QML and Qt Quick applications in mobile
Develop Qt 3D components using QML and JavaScript
Show how to develop plugins and SDKs using Qt
Cover the multi-threading technologies provided by Qt
Build an IPC mechanism using sockets
Serialize data using XML, JSON, and binary format
Interact with a gamepad using Qt Gamepad
We'll cover all this and much, much more.
Note that you can take a look at Chapter 14, Qt Hat Tips and Tricks, whenever you want if you want to get some development candies and see some code snippets that might make your development more pleasurable.
And most importantly, have fun writing Qt applications!
Who this book is for
This book will appeal to developers and programmers who would like to build GUI-based applications. You should be fluent in C++ and the object-oriented paradigm. Qt knowledge is recommended but is not necessary.
What this book covers
Chapter 1, Get Your Qt Feet Wet, lays the fundamentals of Qt and refreshes your memory with a todo application. This chapter covers the Qt project structure, how to use the designer, basic principles of the signals and slots mechanism, and introduces new features of C++14.
Chapter 2, Discovering QMake Secrets, takes a deep dive in the heart of the Qt compilation system: qmake. This chapter will help you understand how it works, how to use it, and how you can structure a Qt application with platform-specific code by designing a system monitoring application.
Chapter 3, Dividing Your Project and Ruling Your Code, analyzes the Qt model/view architecture and how a project can be organized by developing a custom library with the core logic of the application. The project example is a persistent gallery application.
Chapter 4, Conquering the Desktop UI, studies the UI perspective of the model/view architecture with a Qt Widget application relying on the library completed in the previous chapter.
Chapter 5, Dominating the Mobile UI, adds the missing part of the gallery application with the mobile version (Android and iOS); the chapter covers it with the use of QML, Qt Quick controls, and QML / C++ interactions.
Chapter 6, Even Qt Deserves a Slice of Raspberry Pi, continues to the road on Qt Quick application with the Qt 3D perspective. This chapter covers how to build a 3D snake game targeted at the Raspberry Pi.
Chapter 7, Third-Party Libraries Without a Headache, covers how a third-party library can be integrated in a Qt project. OpenCV will be integrated with an image filter application that also provides a custom QDesigner plugin.
Chapter8, Animations, It's Alive, Alive!, extends the image filter application by adding animations and the ability to distribute a custom SDK to let other developers add their own filters.
Chapter 9, Keeping Your Sanity with Multithreading, investigates the multithreading facilities provided by Qt by building a multithreaded Mandelbrot fractal drawing application.
Chapter 10, Need IPC? Get Your Minions to Work, broadens the Mandelbrot fractal application by moving the calculation to other processes and managing the communication using sockets.
Chapter 11, Having Fun with Serialization, covers multiple serialization formats (JSON, XML, and binary) inside a drum machine application in which you can record and load sound loops.
Chapter 12, You Shall (Not) Pass with QTest, adds tests to the drum machine application and studies how the Qt Test frameworks can be used to make unit tests, benchmarking, and GUI events simulation.
Chapter 13, All Packed and Ready to Deploy, gives insights into how to package an application on all desktop OSes (Windows, Linux, and Mac) and mobile platforms (Android and iOS).
Chapter 14, Qt Hat Tips and Tricks, gathers some tips and tricks to develop with Qt with pleasure. It shows how to manage sessions in Qt Creator, useful Qt Creator keyboard shortcuts, how you can customize the logging, save it to disk, and much more.
To get the most out of this book
All the code in this book can be compiled and run from Qt Creator using Qt 5.11. You can do it from your preferred OS: Windows, Linux, or Mac.
About the mobile-specific chapters, either an Android or an iOS device works, but it is not mandatory (the simulator/emulator can be enough).
Chapter 6, Even Qt Deserves a Slice of Raspberry Pi, offers to build an application running on a Raspberry Pi. Although it is more fun if we can do it with a real Raspberry Pi, it is not necessary to have one to complete the chapter.
Download the example code files
You can download the example code files for this book from your account at www.packtpub.com. If you purchased this book elsewhere, you can visit www.packtpub.com/support and register to have the files emailed directly to you.
You can download the code files by following these steps:
Log in or register at
www.packtpub.com
.
Select the
SUPPORT
tab.
Click on
Code Downloads & Errata
.
Enter the name of the book in the
Search
box and follow the onscreen instructions.
Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:
WinRAR/7-Zip for Windows
Zipeg/iZip/UnRarX for Mac
7-Zip/PeaZip for Linux
The code bundle for the book is also hosted on GitHub athttps://github.com/PacktPublishing/Mastering-Qt-5-Second-Editon. In case there's an update to the code, it will be updated on the existing GitHub repository.
We also have other code bundles from our rich catalog of books and videos available athttps://github.com/PacktPublishing/. Check them out!
Get in touch
Feedback from our readers is always welcome.
General feedback: Email [email protected] and mention the book title in the subject of your message. If you have questions about any aspect of this book, please email us at [email protected].
Errata: Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you have found a mistake in this book, we would be grateful if you would report this to us. Please visit www.packtpub.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details.
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Reviews
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Get Your Qt Feet Wet
If you know C++ but have never touched Qt, or if you have already made some intermediate Qt applications, this chapter will ensure that your Qt foundations are solid before studying advanced concepts in the following chapters.
We will teach you how to create a simple todo application using Qt Creator. This application will display a list of tasks that you can create/update/delete. We will cover the Qt Creator and Qt Designer interfaces, an introduction to the signal/slot mechanism, the creation of a custom widget with custom signals/slots, and its integration into your application.
You will implement a todo app using new C++14 semantics: lambdas, auto variables, and for loops. Each of these concepts will be explained in depth and will be used throughout this book.
By the end of this chapter, you will be able to create a desktop application with a flexible UI using Qt widgets and new C++ semantics.
In this chapter, we will cover the following topics:
Qt project basic structure
MainWindow structure
Qt Designer interface
Signals and slots
Custom
QWidget
C++14 lambda, auto, and for each
Qt Designer interface
Qt Designer is a major tool for developing Qt applications. This WYSIWYG editor will help you to easily design your GUI. If you switch between Edit mode and Design mode for the MainWindow.ui file, you will see the real XML content and the designer:
The designer displays several parts:
Form Editor (
1
): A visual representation of the form (empty for now)
Widget Box (
2
): Contains all the major widgets that can be used with your form
Object Inspector (
3
): Displays your form as a hierarchical tree
Property Editor (
4
): Enumerates the properties of the selected widget
Action Editor/Signal & Slots Editor (
5
): Handles toolbar actions and connections between your objects
It's time to embellish this empty window! Let's drag and drop a Label widget from the Display Widgets section on the form. You can change the name and the text properties directly from the Properties editor.
As we are making a todo application, we suggest these properties:
objectName
:
statusLabel
text
:
Status: 0 todo / 0 done
This label will later display the count of todo tasks and the count of tasks already done. Save, build, and start your application. You should now see your new label in the window.
You can now add a push button with those properties:
objectName
:
addTaskButton
text
:
Add task
You should get a result close to the following:
The design of the MainWindow.ui file is ready, we can now study the signals and slots.
