PyQt5实现简易计算器

第一步：使用QtDesigner设计出理想的计算器界面，再将.ui文件自动生成.py文件

界面对应代码

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

# Form implementation generated from reading ui file 'UI_Calculator.ui'
#
# Created by: PyQt5 UI code generator 5.15.4
#
# 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_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(492, 343)
        icon = QtGui.QIcon()
        icon.addPixmap(QtGui.QPixmap("C:/Users/86178/Pictures/Saved Pictures/屏幕截图 2022-02-02 220646.ico"), QtGui.QIcon.Normal, QtGui.QIcon.Off)
        Form.setWindowIcon(icon)
        self.b_close = QtWidgets.QPushButton(Form)
        self.b_close.setEnabled(True)
        self.b_close.setGeometry(QtCore.QRect(150, 110, 93, 28))
        self.b_close.setObjectName("b_close")
        self.b_clear = QtWidgets.QPushButton(Form)
        self.b_clear.setEnabled(True)
        self.b_clear.setGeometry(QtCore.QRect(350, 110, 93, 28))
        self.b_clear.setObjectName("b_clear")
        self.lineEdit = QtWidgets.QLineEdit(Form)
        self.lineEdit.setGeometry(QtCore.QRect(48, 30, 391, 71))
        font = QtGui.QFont()
        font.setFamily("Arial")
        font.setPointSize(26)
        self.lineEdit.setFont(font)
        self.lineEdit.setObjectName("lineEdit")
        self.b_del = QtWidgets.QPushButton(Form)
        self.b_del.setEnabled(True)
        self.b_del.setGeometry(QtCore.QRect(251, 111, 93, 28))
        self.b_del.setObjectName("b_del")
        self.layoutWidget = QtWidgets.QWidget(Form)
        self.layoutWidget.setGeometry(QtCore.QRect(48, 150, 397, 143))
        self.layoutWidget.setObjectName("layoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.layoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.b7 = QtWidgets.QPushButton(self.layoutWidget)
        self.b7.setObjectName("b7")
        self.horizontalLayout.addWidget(self.b7)
        self.b8 = QtWidgets.QPushButton(self.layoutWidget)
        self.b8.setObjectName("b8")
        self.horizontalLayout.addWidget(self.b8)
        self.b9 = QtWidgets.QPushButton(self.layoutWidget)
        self.b9.setObjectName("b9")
        self.horizontalLayout.addWidget(self.b9)
        self.b_plus = QtWidgets.QPushButton(self.layoutWidget)
        self.b_plus.setObjectName("b_plus")
        self.horizontalLayout.addWidget(self.b_plus)
        self.verticalLayout.addLayout(self.horizontalLayout)
        self.horizontalLayout_2 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_2.setObjectName("horizontalLayout_2")
        self.b4 = QtWidgets.QPushButton(self.layoutWidget)
        self.b4.setObjectName("b4")
        self.horizontalLayout_2.addWidget(self.b4)
        self.b5 = QtWidgets.QPushButton(self.layoutWidget)
        self.b5.setObjectName("b5")
        self.horizontalLayout_2.addWidget(self.b5)
        self.b6 = QtWidgets.QPushButton(self.layoutWidget)
        self.b6.setObjectName("b6")
        self.horizontalLayout_2.addWidget(self.b6)
        self.b_sub = QtWidgets.QPushButton(self.layoutWidget)
        self.b_sub.setObjectName("b_sub")
        self.horizontalLayout_2.addWidget(self.b_sub)
        self.verticalLayout.addLayout(self.horizontalLayout_2)
        self.horizontalLayout_3 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_3.setObjectName("horizontalLayout_3")
        self.b1 = QtWidgets.QPushButton(self.layoutWidget)
        self.b1.setObjectName("b1")
        self.horizontalLayout_3.addWidget(self.b1)
        self.b2 = QtWidgets.QPushButton(self.layoutWidget)
        self.b2.setObjectName("b2")
        self.horizontalLayout_3.addWidget(self.b2)
        self.b3 = QtWidgets.QPushButton(self.layoutWidget)
        self.b3.setObjectName("b3")
        self.horizontalLayout_3.addWidget(self.b3)
        self.b_mul = QtWidgets.QPushButton(self.layoutWidget)
        self.b_mul.setObjectName("b_mul")
        self.horizontalLayout_3.addWidget(self.b_mul)
        self.verticalLayout.addLayout(self.horizontalLayout_3)
        self.horizontalLayout_4 = QtWidgets.QHBoxLayout()
        self.horizontalLayout_4.setObjectName("horizontalLayout_4")
        self.point = QtWidgets.QPushButton(self.layoutWidget)
        self.point.setObjectName("point")
        self.horizontalLayout_4.addWidget(self.point)
        self.b0 = QtWidgets.QPushButton(self.layoutWidget)
        self.b0.setObjectName("b0")
        self.horizontalLayout_4.addWidget(self.b0)
        self.b_eq = QtWidgets.QPushButton(self.layoutWidget)
        self.b_eq.setObjectName("b_eq")
        self.horizontalLayout_4.addWidget(self.b_eq)
        self.b_div = QtWidgets.QPushButton(self.layoutWidget)
        self.b_div.setObjectName("b_div")
        self.horizontalLayout_4.addWidget(self.b_div)
        self.verticalLayout.addLayout(self.horizontalLayout_4)

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

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "计算器"))
        self.b_close.setText(_translate("Form", "close"))
        self.b_clear.setText(_translate("Form", "clear"))
        self.b_del.setText(_translate("Form", "del"))
        self.b7.setText(_translate("Form", "7"))
        self.b8.setText(_translate("Form", "8"))
        self.b9.setText(_translate("Form", "9"))
        self.b_plus.setText(_translate("Form", "+"))
        self.b4.setText(_translate("Form", "4"))
        self.b5.setText(_translate("Form", "5"))
        self.b6.setText(_translate("Form", "6"))
        self.b_sub.setText(_translate("Form", "-"))
        self.b1.setText(_translate("Form", "1"))
        self.b2.setText(_translate("Form", "2"))
        self.b3.setText(_translate("Form", "3"))
        self.b_mul.setText(_translate("Form", "*"))
        self.point.setText(_translate("Form", "."))
        self.b0.setText(_translate("Form", "0"))
        self.b_eq.setText(_translate("Form", "="))
        self.b_div.setText(_translate("Form", "/"))

第二步：新建一个.py文件实现具体的逻辑功能

这里的逻辑功能主要是将clicked()信号与自定义的槽相关联实现按钮单击后的反馈。

eval()函数可以实现计算字符串表达式的结果，那么就可以将计算器设计为单击数字键和操作符时向lineEdit中加入对应字符，单击clear时调用clear()函数实现清空，单击del时调用backspace()函数实现退格，单击'='时调用eval()函数实现计算。

逻辑对应代码

import sys
from UI_Calculator import Ui_Form
from PyQt5.QtWidgets import QApplication,QWidget

class Calculator(QWidget,Ui_Form):
    def __init__(self):
        super(Calculator, self).__init__()
        self.setupUi(self)
        self.action()
        self.show()

    def action(self):
        self.b0.clicked.connect(lambda:self.onClick_b0())
        self.b1.clicked.connect(lambda:self.onClick_b1())
        self.b2.clicked.connect(lambda:self.onClick_b2())
        self.b3.clicked.connect(lambda:self.onClick_b3())
        self.b4.clicked.connect(lambda:self.onClick_b4())
        self.b5.clicked.connect(lambda:self.onClick_b5())
        self.b6.clicked.connect(lambda:self.onClick_b6())
        self.b7.clicked.connect(lambda:self.onClick_b7())
        self.b8.clicked.connect(lambda:self.onClick_b8())
        self.b9.clicked.connect(lambda:self.onClick_b9())
        self.b_plus.clicked.connect(lambda:self.onClick_b_plus())
        self.b_sub.clicked.connect(lambda:self.onClick_b_sub())
        self.b_mul.clicked.connect(lambda:self.onClick_b_mul())
        self.b_div.clicked.connect(lambda:self.onClick_b_div())
        self.point.clicked.connect(lambda:self.onClick_point())
        self.b_del.clicked.connect(lambda:self.onClick_b_del())
        self.b_clear.clicked.connect(lambda:self.onClick_b_clear())
        self.b_close.clicked.connect(lambda:self.onClick_b_close())
        self.b_eq.clicked.connect(lambda:self.onClick_b_eq())

    def onClick_b0(self):
        self.lineEdit.insert('0')
    def onClick_b1(self):
        self.lineEdit.insert('1')
    def onClick_b2(self):
        self.lineEdit.insert('2')
    def onClick_b3(self):
        self.lineEdit.insert('3')
    def onClick_b4(self):
        self.lineEdit.insert('4')
    def onClick_b5(self):
        self.lineEdit.insert('5')
    def onClick_b6(self):
        self.lineEdit.insert('6')
    def onClick_b7(self):
        self.lineEdit.insert('7')
    def onClick_b8(self):
        self.lineEdit.insert('8')
    def onClick_b9(self):
        self.lineEdit.insert('9')
    def onClick_b_plus(self):
        self.lineEdit.insert('+')
    def onClick_b_sub(self):
        self.lineEdit.insert('-')
    def onClick_b_mul(self):
        self.lineEdit.insert('*')
    def onClick_b_div(self):
        self.lineEdit.insert('/')
    def onClick_point(self):
        self.lineEdit.insert('.')
    def onClick_b_del(self):
        self.lineEdit.backspace()
    def onClick_b_clear(self):
        self.lineEdit.clear()
    def onClick_b_close(self):
        app=QApplication.instance()
        app.quit()
    def onClick_b_eq(self):
        text=self.lineEdit.text()
        try:
            result=eval(text)
            self.lineEdit.setText(str(eval(text)))
        except:
            self.lineEdit.setText('check your input')

if __name__=='__main__':
    app=QApplication(sys.argv)
    cal=Calculator()
    sys.exit(app.exec_())