Pyqt5: Chapter 1, Section 1: creating a user interface using QT components - Introduction

Catalog

One 、 Introduce

Two 、PyQt

3、 ... and 、 Create a GUI The method of application

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This chapter studies content ：

• Show a greeting
• Use Radio Button Components
• Radio Button grouping
• Show checkbox Form options
• Show two groups checkbox Components

One 、 Introduce

Next , We will learn how to use Qt Toolbox to create a GUI Applications .Qt hold-all , abbreviation Qt, By Trolltech Developed a cross platform application UI frame , Used to develop GUI Applications . It can run on multiple platforms , Include ：Windows、maxOS、Linux And other classes UNIX platform . It is sometimes often referred to as a component library , Because it refers to the design GUI Various components required , Such as ：buttons、labels、textboxes、push buttons and list boxes. It includes a collection of cross platform classes , It integrates development tools and a cross platform IDE. To create a real-time application , We're going to use Python The binding of Qt hold-all , namely PyQt.

Two 、PyQt

PyQt It's a Python Bound cross platform framework , Combine all Qt and Python Characteristics of , So called PyQt, You can use Python Code calls Qt library , That is to say, it can be used Python Language writing Qt GUI Applications . let me put it another way ,PyQt You are allowed to pass Python Code access Qt  All functions provided .PyQt Depend on Qt Library to run programs , So when you install  PyQt when , It will also be automatically installed on your machine at the same time Qt Environmental Science .

One GUI The application may include a main window and some dialog boxes , Or just one dialog . A small GUI Applications typically include at least one dialog box . A dialog application also contains several button components . The menu bar cannot be used in the dialog box 、 The toolbar 、 status bar , Or a Central Central components , However, a main window application can contain all the above components .

There are two types of dialog boxes ：

• Modal（ Modality ）： It is a dialog box that can prevent users from interacting with other parts of the application . Users can only operate in this dialog . Other parts cannot be operated until the dialog box is closed .
• Modeless（ Modeless ）： This dialog is the opposite of modal dialog . When an modeless dialog opens , Users can freely operate the dialog box and other contents in the application except this dialog box .

3、 ... and 、 Create a GUI The method of application

There are two ways to write GUI Applications ：

• Start with the sketch , Use a simple text editor text editor
• Use Qt Designer, A visual design tool , It allows you to quickly create a user interface by dragging

You will be in PyQt Use in Qt Designer To develop a GUI Applications , Because it is a fast and simple way to design user interface , You don't need to write too much code . therefore , You can double-click on the desktop Qt Designer Icon open Qt Designer.

After opening ,Qt Designer You will be asked to choose a template to start your application , As shown in the figure below ：

Qt Designer Some templates for different kinds of applications are provided . You can choose any template , And then click Create Button .

For new applications ,Qt Designer The following predefined templates are provided ：

• Dialog with Buttons Bottom： This template will create a form , And a OK Button and a Cancel Button .
• Dialog with Buttons Right： This template will create a form , And a OK Button and a Cancel Button .
• Dialog without Buttons： This template will create an empty form , You can place components on the form . Its parent class is QDialog.
• Main Window： This template provides a main application form , It contains a menu bar and a toolbar , You can remove it if you don't need it .
• Widget： This template will create an inheritance from QWidget Class rather than QDialog Class .

every last GUI Applications have a top-level component , Other components are sub components of the top-level component . This top-level component can be QDialog、QWidget Or is it QMainWindow, You can select the corresponding template according to your needs . If you want to create an application based on dialog templates , Then the top-level component of the dialog box or its parent component needs to inherit  QDialog class . Empathy , If you want to create an application based on the main form template , Then its top-level component is QMainWindow class , If you want to create one based on Widget The components of , You need to inherit from QWidget class . As mentioned above , Other components used in the user interface are subclasses of related components .

Qt Designer A menu bar and a toolbar are displayed at the top . The various components used to develop the application are grouped in the toolbox on the left . All you need to do is drag the component into the form , And put it wherever you want . You can also layout components , Set their styles , Provide the initial properties of the component , Signals and slots connecting them .