【开发平台】ubuntu14 + python3 + PyQt5
【运行界面】
【源代码】
# -*- coding: utf-8 -*-
'''
Description: A simple calculater based on PyQt5
Author: waterfronter
Last Edit: 2017.10.15
'''
import sys
import re
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QVBoxLayout, QGridLayout, QGroupBox, QLineEdit
from PyQt5.QtCore import Qt
class Calculater(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.setWindowTitle('Calculater')
self.setGeometry(100, 100, 350, 150)
#禁用最大化按钮
self.setWindowFlags(Qt.WindowMinimizeButtonHint | Qt.WindowCloseButtonHint)
#显示区
self.resultflag = 0
self.errflag = 0
self.display = QLineEdit('0')
self.display.setReadOnly(True)
self.display.setAlignment(Qt.AlignRight)
self.display.setMaxLength(30)
#操作区
self.createGridLayout()
windowLayout = QVBoxLayout()
windowLayout.addWidget(self.display)
windowLayout.addWidget(self.horizontalGroupBox)
self.setLayout(windowLayout)
self.show()
def createGridLayout(self):
self.horizontalGroupBox = QGroupBox('')
layout = QGridLayout()
#操作区第1行
button00 = QPushButton('Backspace')
button00.clicked.connect(self.on_click)
layout.addWidget(button00, 0, 0)
button01 = QPushButton('Clear')
button01.clicked.connect(self.on_click)
layout.addWidget(button01, 0, 1)
button02 = QPushButton('Clear All')
button02.clicked.connect(self.on_click)
layout.addWidget(button02, 0, 2)
button03 = QPushButton('/')
button03.clicked.connect(self.on_click)
layout.addWidget(button03, 0, 3)
#操作区第2行
button10 = QPushButton('7')
button10.clicked.connect(self.on_click)
layout.addWidget(button10, 1, 0)
button11 = QPushButton('8')
button11.clicked.connect(self.on_click)
layout.addWidget(button11, 1, 1)
button12 = QPushButton('9')
button12.clicked.connect(self.on_click)
layout.addWidget(button12, 1, 2)
button13 = QPushButton('*')
button13.clicked.connect(self.on_click)
layout.addWidget(button13, 1, 3)
#操作区第3行
button20 = QPushButton('4')
button20.clicked.connect(self.on_click)
layout.addWidget(button20, 2, 0)
button21 = QPushButton('5')
button21.clicked.connect(self.on_click)
layout.addWidget(button21, 2, 1)
button22 = QPushButton('6')
button22.clicked.connect(self.on_click)
layout.addWidget(button22, 2, 2)
button23 = QPushButton('-')
button23.clicked.connect(self.on_click)
layout.addWidget(button23, 2, 3)
#操作区第4行
button30 = QPushButton('1')
button30.clicked.connect(self.on_click)
layout.addWidget(button30, 3, 0)
button31 = QPushButton('2')
button31.clicked.connect(self.on_click)
layout.addWidget(button31, 3, 1)
button32 = QPushButton('3')
button32.clicked.connect(self.on_click)
layout.addWidget(button32, 3, 2)
button33 = QPushButton('+')
button33.clicked.connect(self.on_click)
layout.addWidget(button33, 3, 3)
#操作区第5行,其中'0'独占1行2列
button40 = QPushButton('0')
button40.clicked.connect(self.on_click)
layout.addWidget(button40, 4, 0, 1, 2) #从4行0列开始占1行2列
button42 = QPushButton('.')
button42.clicked.connect(self.on_click)
layout.addWidget(button42, 4, 2, 1, 1) #从4行2列开始占1行1列
button43 = QPushButton('=')
button43.clicked.connect(self.on_click)
layout.addWidget(button43, 4, 3, 1, 1) #从4行3列开始占1行1列
self.horizontalGroupBox.setLayout(layout)
def on_click(self):
source = self.sender()
#全部输入清零
if source.text() == 'Clear All':
self.display.setText('0')
#删除最近输入的一个操作数
elif source.text() == 'Clear':
if self.resultflag != 1:
clrreg = re.compile(r'[0-9.]+$')
substr = clrreg.sub('', self.display.text())
if substr == '':
substr = '0'
self.display.setText(substr)
#退格键功能
elif source.text() == 'Backspace':
if self.resultflag != 1:
if len(self.display.text()) <= 1:
newtext = '0'
else:
newtext = self.display.text()[0 : (len(self.display.text()) - 1)]
self.display.setText(newtext)
#计算输入的算术表达式并将结果显示
elif source.text() == '=':
if self.resultflag != 1:
try:
disstr = self.display.text()[:]
#考虑表达式不完整的情况处理：尾部为运算符*/则补1
if disstr[len(disstr) - 1 : ] in '*/':
calstr = disstr + '1'
#尾部为运算符+-或小数点则补0
elif disstr[len(disstr) - 1 : ] in '+-.':
calstr = disstr + '0'
else:
calstr = disstr[:]
result = str(eval(calstr))
#考虑除0异常处理
except (ZeroDivisionError, Exception) as errinfo:
result = 'Error: '+ str(errinfo)
self.errflag = 1
self.display.setText(result)
self.resultflag = 1
#输入数字或小数点：将算术表达式输入同步显示出来
else:
self.numhandle()
def numhandle(self):
rawstr = self.display.text()[:]
strlen = len(rawstr)
lastchar = rawstr[strlen-1 : ]
inchar = self.sender().text()[:]
newstr = ''
#前面输入尚未计算结果
if self.resultflag != 1:
#当前最后一个字符为运算符（+-*/）
if lastchar in '+-*/':
#输入为0-9 -> 直接追加
if inchar in '0123456789':
newstr = rawstr + inchar
#输入为运算符 -> 忽略输入
elif inchar in '+-*/':
newstr = rawstr[:]
#输入为小数点 -> 小数点前补0再追加
else:
newstr = rawstr + '0' + inchar
#当前最后一个字符为小数点
elif lastchar == '.':
#输入为0-9 -> 直接追加
if inchar in '0123456789':
newstr = rawstr + inchar
#输入为小数点 -> 忽略输入
elif inchar == '.':
newstr = rawstr[:]
#输入为运算符 -> 运算符前补0再追加
else:
newstr = rawstr + '0' + inchar
#当前最后一个字符为0-9
else:
numreg1 = re.compile(r'[+\-*/]{0,1}[0-9]+\.[0-9]*[0-9]$')
srchrslt1 = numreg1.search(rawstr)
#当前最后一个数字前面已经有小数点
if srchrslt1 != None:
#输入为小数点 -> 忽略输入
if inchar == '.':
newstr = rawstr[:]
#输入为0-9或运算符 -> 直接追加
else:
newstr = rawstr + inchar
#当前最后一个数字前面没有小数点
else:
numreg2 = re.compile(r'[+\-*/]0$')
srchrslt2 = numreg2.search(rawstr)
#当前最后一个字符为0且作为最近运算符后的第一个数字
if srchrslt2 != None:
#输入为小数点或运算符 -> 直接追加
if inchar == '.' or inchar in '+-*/':
newstr = rawstr + inchar
#输入为0-9 -> 忽略输入
else:
newstr = rawstr[:]
#当前字符串即是'0'
elif rawstr == '0':
#输入为0-9 -> 用输入取代原字符'0'
if inchar in '0123456789':
newstr = inchar[:]
#输入为小数点或运算符 -> 直接追加
else:
newstr = rawstr + inchar
#其他情况均可直接追加
else:
newstr = rawstr + inchar
#前面输入已经计算出结果
else:
#考虑计算有无异常
if self.errflag == 0:
#输入为运算符 -> 直接追加
if inchar in '+-*/':
newstr = rawstr + inchar
#输入小数点 -> 以小数点前补0刷新显示
elif inchar == '.':
newstr = '0' + inchar
#输入0-9 -> 以输入刷新显示
else:
newstr = inchar[:]
else:
#输入为运算符 -> 忽略输入并擦除err信息
if inchar in '+-*/':
newstr = '0'
#输入小数点 -> 以小数点前补0刷新显示
elif inchar == '.':
newstr = '0' + inchar
#输入0-9 -> 以输入刷新显示
else:
newstr = inchar[:]
self.errflag = 0
self.resultflag = 0
self.display.setText(newstr)
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Calculater()
sys.exit(app.exec_())