Qt开发总结（3）——Qt类库概述

Qt归根到底是一个强大的C++类库，这些大量的类根据功能分为各种模块。

Qt基本模块（Qt Essentials）

Qt基本模块提供了Qt在所有平台的基本功能，它们在所有的开发平台和目标平台上都能用。Qt跨平台的特性基本在这个模块实现。

模块	描述
Qt Core	Core non-graphical classes used by other modules.
Qt GUI	Base classes for graphical user interface (GUI) components. Includes OpenGL.
Qt Multimedia	Classes for audio, video, radio and camera functionality.
Qt Multimedia Widgets	Widget-based classes for implementing multimedia functionality.
Qt Network	Classes to make network programming easier and more portable.
Qt QML	Classes for QML and JavaScript languages.
Qt Quick	A declarative framework for building highly dynamic applications with custom user interfaces.
Qt Quick Controls	Reusable Qt Quick based UI controls to create classic desktop-style user interfaces.
Qt Quick Dialogs	Types for creating and interacting with system dialogs from a Qt Quick application.
Qt Quick Layouts	Layouts are items that are used to arrange Qt Quick 2 based items in the user interface.
Qt SQL	Classes for database integration using SQL.
Qt Test	Classes for unit testing Qt applications and libraries.
Qt Widgets	Classes to extend Qt GUI with C++ widgets.

Qt Core是Qt类库的核心，所有其他模块都依赖于该模块。也即新建一个Qt功能，Qt Core模块是被自动添加到工程中的。在运行时，也必须链接QtCore.dll.

Qt GUI模块提供了用于开发GUI应用程序的必要的类。在新建一个GUI应用程序时，该模块是被自动添加到工程中的。

其他模块通常不会自动添加到项目中，如果需要使用某个模块，可以在新建项目时选择它，也可以在工程的Qt setting中选择它。如果你习惯用Qt Creator开发，那么你只要在Pro文件中加入（加入网络支持模块）：

QT += Network

Qt附加模块（Qt Add-Ons）

Qt附加模块可是实现一些特定目的。这些模块可能只在某些开发平台上有，或只能用于某些特定的操作系统。在安装Qt时可以选择性安装这些模块。

模块	开发平台	运行平台	描述
Active Qt	Windows	Classes for applications which use ActiveX and COM
Qt 3D	All	Functionality for near-realtime simulation systems with support for 2D and 3D rendering.
Enginio (Deprecated)	All	All	A Backend-as-a-Service solution to ease the backend development for connected and data-driven applications.
Qt Android Extras	All	Android	Provides platform-specific APIs for Android.
Qt Bluetooth	All	Android, iOS, Linux and macOS	Provides access to Bluetooth hardware.
Qt Canvas 3D	All	Enables OpenGL-like 3D drawing calls from Qt Quick applications using JavaScript.
Qt Concurrent	Classes for writing multi-threaded programs without using low-level threading primitives.
Qt D-Bus	All	Classes for inter-process communication over the D-Bus protocol.
Qt Gamepad	All	Android, iOS, macOS, tvOS (including the tvOS remote), Linux, Windows	Enables Qt applications to support the use of gamepad hardware.
Qt Graphical Effects	All	Graphical effects for use with Qt Quick 2.
Qt Image Formats	All	Plugins for additional image formats: TIFF, MNG, TGA, WBMP.
Qt Location	All	All	Displays map, navigation, and place content in a QML application.
Qt Mac Extras	All	macOS	Provides platform-specific APIs for macOS.
Qt NFC	All	Android and Linux	Provides access to Near-Field communication (NFC) hardware.
Qt OpenGL (Deprecated)	OpenGL support classes. Deprecated in favor of the QOpenGL* classes in the Qt GUI module.
Qt Platform Headers	Provides classes that encapsulate platform-specific information, tied to a given runtime configuration of a platform plugin.
Qt Positioning	All	Android, iOS, macOS, Linux, WinRT.	Provides access to position, satellite and area monitoring classes.
Qt Print Support	All	Classes to make printing easier and more portable.
Qt Purchasing	All	Android, iOS, and macOS.	Enables in-app purchase of products in Qt applications.
Qt Quick Controls 2	All	Provides lightweight QML types for creating performant user interfaces for embedded and mobile devices. These controls achieve improved efficiency by employing a simplified styling architecture when compared to Qt Quick Controls. These types work in conjunction with Qt Quick and Qt Quick Layouts.
Qt Quick Extras	All	Provides a specialized set of controls that can be used to build interfaces in Qt Quick.
Qt Quick Widgets	All	Provides a C++ widget class for displaying a Qt Quick user interface.
Qt Script (Deprecated)	All	Classes for making Qt applications scriptable. Deprecated in favor of the QJS* classes in the Qt QML module.
Qt SCXML	All	All	Provides classes and tools for creating state machines from SCXML files and embedding them in applications.
Qt Script Tools (Deprecated)	All	Additional components for applications that use Qt Script.
Qt Sensors	All	Android, Qt for iOS, WinRT and Mer.	Provides access to sensor hardware and motion gesture recognition.
Qt Serial Bus	Linux	Linux and Boot to Qt targets.	Provides access to serial industrial bus interface. Currently the module supports the CAN bus and Modbus protocols.
Qt Serial Port	All	Windows, Linux, and macOS.	Provides access to hardware and virtual serial ports.
Qt SVG	All	Classes for displaying the contents of SVG files. Supports a subset of the SVG 1.2 Tiny standard.
Qt WebChannel	All	All	Provides access to QObject or QML objects from HTML clients for seamless integration of Qt applications with HTML/JavaScript clients.
Qt WebEngine	All	Windows, Linux, and macOS.	Classes and functions for embedding web content in applications using the Chromium browser project.
Qt WebSockets	All	All	Provides WebSocket communication compliant with RFC 6455.
Qt WebView	All	Platforms with a native web engine.	Displays web content in a QML application by using APIs native to the platform, without the need to include a full web browser stack.
Qt Windows Extras	All	Windows	Provides platform-specific APIs for Windows.
Qt X11 Extras	All	Linux/X11	Provides platform-specific APIs for X11.
Qt XML	C++ implementations of SAX and DOM. Note: This module is not required to use QXmlStreamReader and QXmlStreamWriter. They are already part of Qt Core.
Qt XML Patterns	Support for XPath, XQuery, XSLT and XML schema validation.
Qt Wayland Compositor	Linux	Linux and Boot to Qt targets.	Provides a framework to develop a Wayland compositor.
Qt Charts	All	UI Components for displaying visually pleasing charts, driven by static or dynamic data models.
Qt Data Visualization	All	All	UI Components for creating stunning 3D data visualizations.
Qt Virtual Keyboard	All	Linux and Windows desktop, and Boot to Qt targets.	A framework for implementing different input methods as well as a QML virtual keyboard. Supports localized keyboard layouts and custom visual themes.

增值模块（Value-Add Modules）

除了随Qt5发布的上述这些模块之外，还有一些模块是单独发布的，这些模块只在商业版许可的Qt中才有。

特性	描述
Qt for Device Creation	Tools for fast, easy, and fully-integrated embedded device application development. Includes most other Value-Add features.
Qt Quick Compiler	Enables compiling .qml source files into application binaries, improving load times and security for code assets.

技术预览模块（Technology Preview Modules）

技术预览模块是一些还处于开发测试阶段的模块。一般来说，技术预览模块中的类在经过几个版本发布后会变成正式模块。例如，Qt5.9中技术预览模块有：

模块	描述
Qt Network Authorization	Provides support for OAuth-based authorization to online services.
Qt Speech	Provides support for accessibility features such as text-to-speech.
Qt Remote Objects	Provides an easy to use mechanism for sharing a QObject's API (Properties/Signals/Slots) between processes or devices.

Qt工具（Qt Tools）

Qt工具在所有支持的平台上都可以使用，用于帮助应用程序的开发和设计。

工具	描述
Qt Designer	Classes for extending Qt Designer.
Qt Help	Classes for integrating online documentation into applications, similar to Qt Assistant.
Qt UI Tools	Classes to handle the forms created in Qt Designer.