Pyqt5 rapid development and practice Chapter 1 understanding pyqt5

PyQt5 Rapid development and actual combat

1. The first 1 Chapter know PyQt5

1.1 PyQt Introduction to the framework

Graphical user interface → GUI

GUI yes Graphical User Interface Short for , Graphical user interface , To be exact ,GUI It is the visual experience and interactive operation of screen products .GUI It's a combination of Computer Science 、 aesthetic 、 psychology 、 Human machine system engineering of behavior and demand analysis in various business fields , Emphasize people — machine - The three environments are designed as a system .

PyQt：

PyQt Is one for creating GUI Cross platform toolkit for applications , It will Python Programming languages and Qt Libraries are successfully integrated .Qt The library is currently the most powerful GUI One of the Libraries .

The biggest problem that open source software needs to solve is how to deal with the situation that developers use open source software to achieve personal or business goals , This includes copyright and revenue issues . When a software developer plans to open source the code he writes , Usually choose free software agreement , namely GPL (GNU General Public License,GNU General public permit ). therefore ,PyQt 5 I chose GPL agreement , So developers can use it with confidence PyQt 5 Development software .

1.1.1 PyQt5 Characteristics

• Based on high performance Qt Of GUI Control set
• Can run across platforms in Windows、Linux and Mac OS Wait for the system .
• Use signal / Slot (signal / slot) Mechanism to communicate
• Yes Qt Complete encapsulation of the Library
• have access to Qt ripe IDE Graphic interface design , And automatically generate executable Python Code
• Provides a wide range of window controls .

1.1.2 Qt And PyQt The relationship between

1. PyQt yes Qt Framework of the Python Language implementation .
2. In terms of development speed , because PyQt The core of Qt library , Also use C++ Compiling , So even if the logic code runs slower , It will not become a performance bottleneck .
3. PyQt towards Python Programmers provide complete Qt Functions of application program interface , Almost usable Python Do anything Qt What can be done .

1.1.3 Introduction to other graphical interface development libraries

• Tkinter

  Tkinter It's bound Python Of Tk GUI Toolset , Namely Python Packaged Tcl Code , By embedding in Python Inside the interpreter Tcl Interpreter implementation . take Tkinter Is converted to Tcl command , And then to Tcl Interpreter to explain , Realization Python Of GUI.

• wxPython

  wxPython yes Python For cross platform GUI Toolset wxWidgets（ use C++ To write ） Packaging , As Python An extension module of .

• PyGTK

  PyGTK yes Python Yes GTK+GUI A series of packages of the Library .

• PySide

  PySide yes Python For cross platform GUI Toolset Qt Another package for , Bundle up Python among .

1.1.4 PyQt4 / PyQt5

PyQt5 No longer downward compatible PyQt 4 Written program , because PyQt5 There are several major changes .

1. PyQt 5 No more Python 2.6 Previous versions provide support ,
2. PytQt5 Some modules have been rebuilt , Some old modules have been discarded
3. PyQt5 What is used OtWebKitWidgets modular (PyQt 5.7 Above version ) It was developed by Google team chromium Kernel engine , Because the update and maintenance speed is very fast , Basically, it perfectly supports the new things of the Internet .
4. PyQt 5 Only new signals and slots are supported , The transfer of old signals and slots will no longer be supported
5. PyQt 5 Does not support the Qt 5.0 Marked as abandoned or obsolete Qt API part
6. PyQt 5 Release when the program needs it GIL

1.1.5 Python2 And Python3

PyQt5 Use Python3 Why ：

• Python 2 The vast majority of the frameworks of the provide support for Python 3 Support for , And some new frameworks such as TensorFlow And so on, only provided right Python 3 Support for .
• about Python 2 The official support only goes to 2020 year , and PyOt 5 It's a new framework , New frameworks often do not provide much support for languages that are about to be phased out .
• Python 3 By default UTF-8 code , Seamless compatibility with Chinese strings .
• Use Python 3 Development PyQt 5, There is no need to consider the problem of Chinese coding .
• PyQt 5 The official default is only to provide Python3 Support for

1.2 PyQt5 Environment building

1.2.1 stay Windows The structures, PyQt5 Environmental Science

1. install Python3 Running environment

   The author directly creates a virtual environment here

   Python Version selected 3.8

   

2. install PyQt5

   pip install PyQt5 -i https://pypi.tuna.tsinghua.edu.cn/simple
   

   

3. install PyQt5-tools

   pip install PyQt5-tools -i https://pypi.tuna.tsinghua.edu.cn/simple
   

   

4. test

   import sys
   from PyQt5 import QtWidgets,QtCore
   
   app = QtWidgets.QApplication(sys.argv)
   widget = QtWidgets.QWidget()
   widget.resize(360,360)
   widget.setWindowTitle("Hello,PyQt5")
   widget.show()
   sys.exit(app.exec_())
   

   

1.2.2 stay Mac OS The structures, PyQt5 Environmental Science

1. install Qt
2. install Python
3. install SIP
4. install PyQt
5. test

1.2.3 PyQt5 Installation test of

help(PyQt5)

1.2.4 Install others Python modular

install matplotlib

1.2.5 Use PyQt5 Of API file

• Method 1： Check... By command PyQt5 All properties of classes and objects

• Method 2： Check the online help documentation

  https://www.riverbankcomputing.com/static/Docs/PyQt5/
  

  

1.3 Eric 6 Installation and use

One Python Editor and IDE, use Python Written , I won't pretend here

After clicking the button , The window closed .