Pyqt 简明教程

PyQt - Major Classes

PyQt API 是大量类和方法的集合。这些类在 20 多个模块中定义。以下是一些常用模块 −

PyQt API is a large collection of classes and methods. These classes are defined in more than 20 modules. Following are some of the frequently used modules −

Sr.No.	Modules & Description
1	QtCore Core non-GUI classes used by other modules
2	QtGui Graphical user interface components
3	QtMultimedia Classes for low-level multimedia programming
4	QtNetwork Classes for network programming
5	QtOpenGL OpenGL support classes
6	QtScript Classes for evaluating Qt Scripts
7	QtSql Classes for database integration using SQL
8	QtSvg Classes for displaying the contents of SVG files
9	QtWebKit Classes for rendering and editing HTML
10	QtXml Classes for handling XML
11	QtAssistant Support for online help
12	QtDesigner Classes for extending Qt Designer

PyQt API 包含 400 多个类。 QObject 类位于类层次结构的顶部。它是所有 Qt 对象的基类。此外， QPaintDevice 类是所有可绘制对象的基类。

PyQt API contains more than 400 classes. The QObject class is at the top of class hierarchy. It is the base class of all Qt objects. Additionally, QPaintDevice class is the base class for all objects that can be painted.

QApplication 类管理 GUI 应用程序的主设置和控制流。它包含主事件循环，在该循环中处理和分派由窗口元素和其他源生成的事件。它还处理系统范围和应用程序范围的设置。

QApplication class manages the main settings and control flow of a GUI application. It contains main event loop inside which events generated by window elements and other sources are processed and dispatched. It also handles system-wide and application-wide settings.

QWidget 类派生自 QObject 和 QPaintDevice 类，是所有用户界面对象的基类。 QDialog 和 QFrame 类也派生自 QWidget 类。它们有自己的子类系统。

QWidget class, derived from QObject and QPaintDevice classes is the base class for all user interface objects. QDialog and QFrame classes are also derived from QWidget class. They have their own sub-class system.

以下图表描绘了它们在层次结构中的某些重要类。

Following diagrams depict some important classes in their hierarchy.

以下是常用的部件精简列表 −

Here is a select list of frequently used widgets −

以下是常用的部件。

Given below are the commonly used Widgets.

Sr.No.	Widgets & Description
1	QLabel Used to display text or image
2	QLineEdit Allows the user to enter one line of text
3	QTextEdit Allows the user to enter multi-line text
4	QPushButton A command button to invoke action
5	QRadioButton Enables to choose one from multiple options
6	QCheckBox Enables choice of more than one options
7	QSpinBox Enables to increase/decrease an integer value
8	QScrollBar Enables to access contents of a widget beyond display aperture
9	QSlider Enables to change the bound value linearly.
10	QComboBox Provides a dropdown list of items to select from
11	QMenuBar Horizontal bar holding QMenu objects
12	QStatusBar Usually at bottom of QMainWindow, provides status information.
13	QToolBar Usually at top of QMainWindow or floating. Contains action buttons
14	QListView Provides a selectable list of items in ListMode or IconMode
15	QPixmap Off-screen image representation for display on QLabel or QPushButton object
16	QDialog Modal or modeless window which can return information to parent window

典型的基于 GUI 的应用程序的顶级窗口由 QMainWindow 小部件对象创建。上面列出的一些小部件在这个主窗口中占据各自指定的位置，而其他一些小部件则使用各种布局管理器放置在中央小部件区域中。

A typical GUI based application’s top level window is created by QMainWindow widget object. Some widgets as listed above take their appointed place in this main window, while others are placed in the central widget area using various layout managers.

下图显示了 QMainWindow 框架 -

The following diagram shows the QMainWindow framework −