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QT5 Blueprints

By : Symeon Huang
Book Image

QT5 Blueprints

By: Symeon Huang

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QT5 Blueprints
Symeon Huang
Mar, 2015 | 272 pages
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Table of Contents (17 chapters)
Qt 5 Blueprints
Qt 5 Blueprints
Credits
Credits
About the Author
About the Author
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Creating Your First Qt Application
Creating Your First Qt Application
Creating a new project
Changing the layout of widgets
Understanding the mechanism of signals and slots
Connecting two signals
Creating a Qt Quick application
Connecting C++ slots to QML signals
Summary
2
Building a Beautiful Cross-platform Clock
Building a Beautiful Cross-platform Clock
Creating a basic digital clock
Tweaking the digital clock
Saving and restoring settings
Building on the Unix platforms
Summary
3
Cooking an RSS Reader with Qt Quick
Cooking an RSS Reader with Qt Quick
Understanding model and view
Parsing RSS Feeds by XmlListModel
Tweaking the categories
Utilizing ScrollView
Adding BusyIndicator
Making a frameless window
Debugging QML
Summary
4
Controlling Camera and Taking Photos
Controlling Camera and Taking Photos
Accessing the camera in Qt
Controlling the camera
Displaying errors on the status bar
Permanent widgets in the status bar
Utilizing the menu bar
Using QFileDialog
QML camera
Summary
5
Extending Paint Applications with Plugins
Extending Paint Applications with Plugins
Drawing via QPainter
Writing static plugins
Writing dynamic plugins
Merging plugins and main program projects
Creating a C++ plugin for QML applications
Summary
6
Getting Wired and Managing Downloads
Getting Wired and Managing Downloads
Introducing Qt network programming
Utilizing QNetworkAccessManager
Making use of the progress bar
Writing multithreaded applications
Managing a system network session
Summary
7
Parsing JSON and XML Documents to Use Online APIs
Parsing JSON and XML Documents to Use Online APIs
Setting up Qt for Android
Parsing JSON results
Parsing XML results
Building Qt applications for Android
Parsing JSON in QML
Summary
8
Enabling Your Qt Application to Support Other Languages
Enabling Your Qt Application to Support Other Languages
Internationalization of Qt applications
Translating Qt Widgets applications
Disambiguating identical texts
Changing languages dynamically
Translating Qt Quick applications
Summary
9
Deploying Applications on Other Devices
Deploying Applications on Other Devices
Releasing Qt applications on Windows
Creating an installer
Packaging Qt applications on Linux
Deploying Qt applications on Android
Summary
10
Don't Panic When You Encounter These Issues
Don't Panic When You Encounter These Issues
Commonly encountered issues
Debugging Qt applications
Debugging Qt Quick applications
Useful resources
Summary
Index
Index

Debugging QML

The most common practice to debug QML is the use of the API console. JavaScript developers should be familiar with this because of the console support in QML. The relationships between the console functions and the Qt/C++ QDebug functions are given as follows:

QML

Qt/C++

console.log()

qDebug()

console.debug()

qDebug()

console.info()

qDebug()

console.warn()

qWarning()

console.error()

qCritical()

With the preceding supports present, QML is just like JavaScript programming. At the same time, the following functions are also introduced in QML:

Functions

Description

console.assert()

This function tests whether the expression is true. If not, it will write an optional message to the console and print the stack trace.

console.exception()

This function prints an error message together with the stack trace of the JavaScript execution at the point it is called.

console.trace()

This function prints the stack trace of the JavaScript execution...

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