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【python】软件开发——PyQt5、Qt Designer、信号与槽机制、计算器实现

扎眼的阳光 • • Python • 阅读 47

PyQt5介绍

PyQt5 是一个基于 Python 的 GUI 框架，用于创建跨平台的桌面应用程序。它是 Qt 库的 Python 绑定，结合了 Python 的简洁和易用性以及 Qt 框架的强大功能。

Qt 是一个流行的 C++ 跨平台应用程序开发框架，提供了丰富的图形界面组件、网络通信、数据库访问、多线程等功能。PyQt5 允许开发者使用 Python 语言来创建 Qt 应用程序，从而可以轻松地利用 Qt 提供的功能，并且能够在多个操作系统上运行，包括 Windows、MacOS、Linux 等。

以下是 PyQt5 的一些特点和功能：

  1. 丰富的图形界面组件：PyQt5 提供了大量的预定义 UI 组件，如按钮、标签、文本框、列表框、表格等，可以用于构建直观、交互式的用户界面。
  2. 事件驱动编程：PyQt5 使用信号与槽（Signals & Slots）机制进行事件处理，通过连接信号与槽函数，可以实现对象之间的通信和事件处理。
  3. 多线程支持：PyQt5 提供了对多线程编程的支持，可以轻松地创建和管理多线程应用程序，充分利用多核处理器的优势。
  4. 数据库访问：PyQt5 集成了 Qt 的 SQL 模块，可以方便地连接和操作各种数据库，如 SQLite、MySQL、PostgreSQL 等。
  5. 绘图和动画：PyQt5 提供了强大的绘图功能，可以绘制各种图形、图表和实现动画效果。
  6. 自定义样式：通过使用 Qt 的样式表语言（QSS），可以轻松地自定义应用程序的外观和风格。
  7. 跨平台支持：由于 PyQt5 基于 Qt 库，因此可以在不同的操作系统上运行，并且保持一致的用户体验和行为。

安装PyQt5

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

PyQt5与Qt Designer

PyQt5 是基于 Python 的 Qt 框架的绑定库，它允许你使用 Python 编程语言来开发 Qt 应用程序。

Qt Designer 是 Qt 提供的一个可视化界面设计工具，用于创建和编辑 Qt 用户界面（UI）文件。

PyQt5 与 Qt Designer 可以很好地配合使用，以加快开发过程并实现界面和功能的分离。

使用Qt Designer

直接打开

不管在Windows，还是在MAC系统下，安装了anaconda后，Qt Designer都会被安装。

在Windows下，启动Qt Designer的路径是：

D:\anaconda3\Library\bin

PyCharm打开

打开PyCharm——>File——>Settings——>Tool——>External Tools——>创建工具

Name：Qtdesigner

Group：Qt

Program：D:\anaconda3\Library\bin\designer.exe

Working directory：$ProjectFileDir$


启动

QtDesigner界面

PyQt5 和 Qt Designer 的使用

使用 Qt Designer 设计界面

在QtDesigner里设计一个计算器ui，保存到项目文件夹

将 UI 文件转换为 Python 代码

  • 通过命令行转换

使用 PyQt5 提供的 pyuic 工具可以将 .ui 文件转换为相应的 Python 代码。

在项目文件夹路径下cmd命令行运行：

pyuic5 input.ui -o output.py

input.ui：ui文件名
output.py：py文件名

  • PyCharm中配置ui文件自动转py文件

打开PyCharm——>File——>Settings——>Tool——>External Tools——>创建工具

Name：pyuic
Group：Qt
Program：D:\anaconda3\python.exe
Arguments：-m PyQt5.uic.pyuic $FileName$ -o $FileNameWithoutExtension$.py
Working directory：$FileDir$


使用步骤


生成的py文件：计算器ui.py

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file '计算器ui.ui'
#
# Created by: PyQt5 UI code generator 5.15.7
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again.  Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(588, 568)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(0, 120, 581, 411))
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.gridLayoutWidget.sizePolicy().hasHeightForWidth())
        self.gridLayoutWidget.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.gridLayoutWidget.setFont(font)
        self.gridLayoutWidget.setObjectName("gridLayoutWidget")
        self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.setContentsMargins(0, 0, 0, 0)
        self.gridLayout.setObjectName("gridLayout")
        self.pushButton_9 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_9.sizePolicy().hasHeightForWidth())
        self.pushButton_9.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_9.setFont(font)
        self.pushButton_9.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_9.setFlat(False)
        self.pushButton_9.setObjectName("pushButton_9")
        self.gridLayout.addWidget(self.pushButton_9, 1, 2, 1, 1)
        self.pushButton_eq = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_eq.sizePolicy().hasHeightForWidth())
        self.pushButton_eq.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_eq.setFont(font)
        self.pushButton_eq.setFlat(False)
        self.pushButton_eq.setObjectName("pushButton_eq")
        self.gridLayout.addWidget(self.pushButton_eq, 4, 2, 1, 2)
        self.pushButton_sub = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_sub.sizePolicy().hasHeightForWidth())
        self.pushButton_sub.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_sub.setFont(font)
        self.pushButton_sub.setFlat(False)
        self.pushButton_sub.setObjectName("pushButton_sub")
        self.gridLayout.addWidget(self.pushButton_sub, 2, 3, 1, 1)
        self.pushButton_5 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_5.sizePolicy().hasHeightForWidth())
        self.pushButton_5.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_5.setFont(font)
        self.pushButton_5.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_5.setFlat(False)
        self.pushButton_5.setObjectName("pushButton_5")
        self.gridLayout.addWidget(self.pushButton_5, 2, 1, 1, 1)
        self.pushButton_RE = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_RE.sizePolicy().hasHeightForWidth())
        self.pushButton_RE.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_RE.setFont(font)
        self.pushButton_RE.setStyleSheet("color: rgb(255, 0, 0);")
        self.pushButton_RE.setFlat(False)
        self.pushButton_RE.setObjectName("pushButton_RE")
        self.gridLayout.addWidget(self.pushButton_RE, 0, 0, 1, 1)
        self.pushButton_prec = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_prec.sizePolicy().hasHeightForWidth())
        self.pushButton_prec.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_prec.setFont(font)
        self.pushButton_prec.setFlat(False)
        self.pushButton_prec.setObjectName("pushButton_prec")
        self.gridLayout.addWidget(self.pushButton_prec, 4, 1, 1, 1)
        self.pushButton_div = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_div.sizePolicy().hasHeightForWidth())
        self.pushButton_div.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_div.setFont(font)
        self.pushButton_div.setFlat(False)
        self.pushButton_div.setObjectName("pushButton_div")
        self.gridLayout.addWidget(self.pushButton_div, 0, 3, 1, 1)
        self.pushButton_8 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_8.sizePolicy().hasHeightForWidth())
        self.pushButton_8.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_8.setFont(font)
        self.pushButton_8.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_8.setFlat(False)
        self.pushButton_8.setObjectName("pushButton_8")
        self.gridLayout.addWidget(self.pushButton_8, 1, 1, 1, 1)
        self.pushButton_4 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_4.sizePolicy().hasHeightForWidth())
        self.pushButton_4.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_4.setFont(font)
        self.pushButton_4.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_4.setFlat(False)
        self.pushButton_4.setObjectName("pushButton_4")
        self.gridLayout.addWidget(self.pushButton_4, 2, 0, 1, 1)
        self.pushButton_0 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_0.sizePolicy().hasHeightForWidth())
        self.pushButton_0.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_0.setFont(font)
        self.pushButton_0.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_0.setFlat(False)
        self.pushButton_0.setObjectName("pushButton_0")
        self.gridLayout.addWidget(self.pushButton_0, 4, 0, 1, 1)
        self.pushButton_6 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_6.sizePolicy().hasHeightForWidth())
        self.pushButton_6.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_6.setFont(font)
        self.pushButton_6.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_6.setFlat(False)
        self.pushButton_6.setObjectName("pushButton_6")
        self.gridLayout.addWidget(self.pushButton_6, 2, 2, 1, 1)
        self.pushButton_M = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_M.sizePolicy().hasHeightForWidth())
        self.pushButton_M.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_M.setFont(font)
        self.pushButton_M.setStyleSheet("color: rgb(255, 85, 0);")
        self.pushButton_M.setFlat(False)
        self.pushButton_M.setObjectName("pushButton_M")
        self.gridLayout.addWidget(self.pushButton_M, 0, 1, 1, 1)
        self.pushButton_mul = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_mul.sizePolicy().hasHeightForWidth())
        self.pushButton_mul.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_mul.setFont(font)
        self.pushButton_mul.setFlat(False)
        self.pushButton_mul.setObjectName("pushButton_mul")
        self.gridLayout.addWidget(self.pushButton_mul, 1, 3, 1, 1)
        self.pushButton_MR = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_MR.sizePolicy().hasHeightForWidth())
        self.pushButton_MR.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_MR.setFont(font)
        self.pushButton_MR.setStyleSheet("color: rgb(255, 85, 0);")
        self.pushButton_MR.setFlat(False)
        self.pushButton_MR.setObjectName("pushButton_MR")
        self.gridLayout.addWidget(self.pushButton_MR, 0, 2, 1, 1)
        self.pushButton_7 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_7.sizePolicy().hasHeightForWidth())
        self.pushButton_7.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_7.setFont(font)
        self.pushButton_7.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_7.setFlat(False)
        self.pushButton_7.setObjectName("pushButton_7")
        self.gridLayout.addWidget(self.pushButton_7, 1, 0, 1, 1)
        self.pushButton_1 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_1.sizePolicy().hasHeightForWidth())
        self.pushButton_1.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_1.setFont(font)
        self.pushButton_1.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_1.setObjectName("pushButton_1")
        self.gridLayout.addWidget(self.pushButton_1, 3, 0, 1, 1)
        self.pushButton_2 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_2.sizePolicy().hasHeightForWidth())
        self.pushButton_2.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_2.setFont(font)
        self.pushButton_2.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_2.setObjectName("pushButton_2")
        self.gridLayout.addWidget(self.pushButton_2, 3, 1, 1, 1)
        self.pushButton_3 = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_3.sizePolicy().hasHeightForWidth())
        self.pushButton_3.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_3.setFont(font)
        self.pushButton_3.setStyleSheet("color: rgb(85, 170, 255);")
        self.pushButton_3.setObjectName("pushButton_3")
        self.gridLayout.addWidget(self.pushButton_3, 3, 2, 1, 1)
        self.pushButton_add = QtWidgets.QPushButton(self.gridLayoutWidget)
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.pushButton_add.sizePolicy().hasHeightForWidth())
        self.pushButton_add.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.pushButton_add.setFont(font)
        self.pushButton_add.setObjectName("pushButton_add")
        self.gridLayout.addWidget(self.pushButton_add, 3, 3, 1, 1)
        self.lcdNumber = QtWidgets.QLCDNumber(self.centralwidget)
        self.lcdNumber.setGeometry(QtCore.QRect(0, 22, 581, 91))
        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Expanding)
        sizePolicy.setHorizontalStretch(0)
        sizePolicy.setVerticalStretch(0)
        sizePolicy.setHeightForWidth(self.lcdNumber.sizePolicy().hasHeightForWidth())
        self.lcdNumber.setSizePolicy(sizePolicy)
        font = QtGui.QFont()
        font.setFamily("Microsoft YaHei")
        font.setPointSize(24)
        self.lcdNumber.setFont(font)
        self.lcdNumber.setDigitCount(18)
        self.lcdNumber.setObjectName("lcdNumber")
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton_9.setText(_translate("MainWindow", "9"))
        self.pushButton_eq.setText(_translate("MainWindow", "="))
        self.pushButton_sub.setText(_translate("MainWindow", "-"))
        self.pushButton_5.setText(_translate("MainWindow", "5"))
        self.pushButton_RE.setText(_translate("MainWindow", "RE"))
        self.pushButton_prec.setText(_translate("MainWindow", "/100"))
        self.pushButton_div.setText(_translate("MainWindow", "/"))
        self.pushButton_8.setText(_translate("MainWindow", "8"))
        self.pushButton_4.setText(_translate("MainWindow", "4"))
        self.pushButton_0.setText(_translate("MainWindow", "0"))
        self.pushButton_6.setText(_translate("MainWindow", "6"))
        self.pushButton_M.setText(_translate("MainWindow", "M"))
        self.pushButton_mul.setText(_translate("MainWindow", "*"))
        self.pushButton_MR.setText(_translate("MainWindow", "MR"))
        self.pushButton_7.setText(_translate("MainWindow", "7"))
        self.pushButton_1.setText(_translate("MainWindow", "1"))
        self.pushButton_2.setText(_translate("MainWindow", "2"))
        self.pushButton_3.setText(_translate("MainWindow", "3"))
        self.pushButton_add.setText(_translate("MainWindow", "+"))

PyCharm运行main.py得到计算器软件窗口

main.py

from PyQt5.QtWidgets import *
from 计算器ui import Ui_MainWindow

# QMainWindow：主窗口类
# Ui_MainWindow：自动生成py文件里的类
class MyMainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self,*args,**kwargs):
        super(MyMainWindow,self).__init__(*args,**kwargs)
        # Ui_MainWindow类里的方法：将ui构造出来
        self.setupUi(self)

if __name__ == "__main__":
    # QApplication实例是 PyQt5应用程序的主要对象
    app = QApplication([])
    # QMainWindow子类实例表示我们的窗口界面
    window = MyMainWindow()
    window.setWindowTitle("计算器")
    window.show()
    # 启动主循环，开始监测并响应用户输入和其他事件。
    app.exec_()

信号与槽（Signals & Slots）机制

  1. 定义了一个自定义对象 MyObject，它包含一个整数参数的信号 my_signal 和一个槽函数 handle_signal。
  2. 创建了 MyObject 的一个实例 obj。
  3. 通过 obj.my_signal.connect(obj.handle_signal) 将信号 my_signal 连接到槽函数 handle_signal 上。这样，当信号被发射时，与之连接的槽函数会被自动调用。
  4. 使用 obj.my_signal.emit(42) 发射信号，并传递整数参数 42。结果就是输出 “Received signal: 42”。
from PyQt5.QtCore import pyqtSignal, QObject

# 定义一个自定义对象，包含一个信号和一个槽函数
class MyObject(QObject):
    # 定义一个带有一个整数参数的信号
    my_signal = pyqtSignal(int)

    def __init__(self):
        super().__init__()

    # 定义一个槽函数，用于接收信号并处理
    def handle_signal(self, data):
        print("Received signal:", data)

# 创建一个 MyObject 的实例
obj = MyObject()

# 连接信号与槽函数
obj.my_signal.connect(obj.handle_signal)

# 发射信号，槽函数会被调用
obj.my_signal.emit(42)

输出结果：

Received signal: 42

实现计算器功能

logic.py

from PyQt5 import QtWidgets

class CalState:
    READY = 0
    INPUT = 1

class CalLogic:
    def __init__(self, lcd_widget: QtWidgets.QLCDNumber):
        # lcd_widget ： QLCDNumber 控件的变量名
        self.lcd_widget = lcd_widget
        # 计算器的状态：ready/input
        self.state = None
        # 存储计算器按下的健
        self.stack = None  # list

        self.last_operation = None
        # 存储当前的操作健
        self.current_operator = None
        # RE、M、MR相关
        self.memory = None

    def init_cal(self):
        """初始化计算器状态"""
        self.state = CalState.READY
        self.stack = [0]
        self.last_operation = None
        self.current_operator = None
        self._display()

    def _display(self):
        """计算器数字显示屏显示"""
        self.lcd_widget.display(self.stack[-1])

    def number_slot(self, num_val):
        """数字0到9显示的槽函数"""
        if self.state == CalState.READY:
            self.stack[-1] = num_val
            self.state = CalState.INPUT
        else:
            self.stack[-1] = self.stack[-1] * 10 + num_val
        self._display()

    def operation_slot(self, oper):
        """+-*/四个按键的槽函数"""
        self.current_operator = oper
        self.state = CalState.INPUT
        self.stack.append(0)  # 每按一次操作健就往stack列表中加入一个元素0

    def perc_slot(self):
        """实现1/100按键的槽函数"""
        self.stack[-1] *= 0.01
        self._display()
        self.state = CalState.INPUT

    def eq_slot(self):
        if self.current_operator:
            try:
                result = self._do_operator(self.stack[0], self.stack[1])
            except Exception:
                self.lcd_widget.display("error")
                self.state = [0]
                return
        self.stack = [result]
        self.current_operator = None
        self.state = CalState.READY
        self._display()     # 显示计算后的结果

    def _do_operator(self, operand1, operand2):
        """执⾏+-*/操作逻辑"""
        if self.current_operator == "+":
            result = operand1 + operand2
        elif self.current_operator == "-":
            result = operand1 - operand2
        elif self.current_operator == "*":
            result = operand1 * operand2
        else:
            result = operand1 / operand2
        return result

    def re_slot(self):
        self.init_cal()

    def m_slot(self):
        #lcd_widget.value()是PyQt5中QLCDNumber 控件的一个方法，用于获取该控件的当前值
        self.memory = self.lcd_widget.value()

    def mr_slot(self):
        self.stack[-1] = self.memory
        self.state = CalState.INPUT
        self._display()

main.py

from PyQt5.QtWidgets import *
from 计算器ui import Ui_MainWindow
from logic import CalLogic

# QMainWindow：主窗口类
# Ui_MainWindow：自动生成py文件里的类
class MyMainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self,*args,**kwargs):
        super(MyMainWindow,self).__init__(*args,**kwargs)
        # Ui_MainWindow类里的方法：将ui构造出来
        self.setupUi(self)
        self.cl:CalLogic = CalLogic(self.lcdNumber)
        self.do_signal_slot()
        self.cl.init_cal()

    def do_signal_slot(self):
        """给数字0到9按键建⽴clicked信号和槽函数"""
        self.pushButton_0.clicked.connect(lambda: self.cl.number_slot(0))
        self.pushButton_1.clicked.connect(lambda: self.cl.number_slot(1))
        self.pushButton_2.clicked.connect(lambda: self.cl.number_slot(2))
        self.pushButton_3.clicked.connect(lambda: self.cl.number_slot(3))
        self.pushButton_4.clicked.connect(lambda: self.cl.number_slot(4))
        self.pushButton_5.clicked.connect(lambda: self.cl.number_slot(5))
        self.pushButton_6.clicked.connect(lambda: self.cl.number_slot(6))
        self.pushButton_7.clicked.connect(lambda: self.cl.number_slot(7))
        self.pushButton_8.clicked.connect(lambda: self.cl.number_slot(8))
        self.pushButton_9.clicked.connect(lambda: self.cl.number_slot(9))

        """给+-*/按键建⽴clicked信号和槽函数"""
        self.pushButton_add.clicked.connect(lambda: self.cl.operation_slot("+"))
        self.pushButton_sub.clicked.connect(lambda: self.cl.operation_slot("-"))
        self.pushButton_mul.clicked.connect(lambda: self.cl.operation_slot("*"))
        self.pushButton_div.clicked.connect(lambda: self.cl.operation_slot("/"))

        """1/100按键建⽴clicked信号和槽函数"""
        self.pushButton_prec.clicked.connect(self.cl.perc_slot)

        """RE,M,MR按键建⽴clicked信号和槽函数"""
        self.pushButton_RE.clicked.connect(self.cl.re_slot)
        self.pushButton_M.clicked.connect(self.cl.m_slot)
        self.pushButton_MR.clicked.connect(self.cl.mr_slot)

        """=按键建⽴clicked信号和槽函数"""
        self.pushButton_eq.clicked.connect(self.cl.eq_slot)

if __name__ == "__main__":
    # QApplication实例是 PyQt5应用程序的主要对象
    app = QApplication([])
    # QMainWindow子类实例表示我们的窗口界面
    window = MyMainWindow()
    window.setWindowTitle("计算器")
    window.show()
    # 启动主循环，开始监测并响应用户输入和其他事件。
    app.exec_()

运行main.py

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