Book Image

Learn Qt 5

By : Nicholas Sherriff
Book Image

Learn Qt 5

By: Nicholas Sherriff

Overview of this book

Qt is a mature and powerful framework for delivering sophisticated applications across a multitude of platforms. It has a rich history in the Linux world, is widely used in embedded devices, and has made great strides in the Mobile arena over the past few years. However, in the Microsoft Windows and Apple Mac OS X worlds, the dominance of C#/.NET and Objective-C/Cocoa means that Qt is often overlooked. This book demonstrates the power and flexibility of the Qt framework for desktop application development and shows how you can write your application once and deploy it to multiple operating systems. Build a complete real-world line of business (LOB) solution from scratch, with distinct C++ library, QML user interface, and QtTest-driven unit-test projects. This is a suite of essential techniques that cover the core requirements for most LOB applications and will empower you to progress from a blank page to shipped application.
Table of Contents (11 chapters)

Network access

The low-level networking protocol negotiation is all handled internally by Qt, and we can easily get connected to the outside world via the QNetworkAccessManager class. To be able to access this functionality, we need to add the network module to

QT += sql network

One of Qt's weaknesses is the lack of interfaces, making unit testing difficult in some cases. If we just use QNetworkAccessManager directly, we won’t be able to test our code without making real calls to the network, which is undesirable. However, a quick and easy solution to this problem is to hide the Qt implementation behind an interface of our own, and we will do that here.

For the purposes of this chapter, all we need to be able to do with the network is check that we have connectivity and send a HTTP GET request. With this in mind, create a header file i-network-access-manager...