在Python中使用 PyQt5 构建计算器
在本文中，我们将了解如何使用 PyQt5 创建计算器，计算器是用于进行数学计算的东西，特别是带有键盘和可视显示器的小型电子设备。下面是计算器的样子
GUI实现步骤
- 创建一个标签以显示数字和输出并设置其几何形状
- 将标签文本从右侧对齐并增加其字体大小
- 为从 0 到 9 的数字创建按钮，并以正确的顺序设置它们的几何形状
- 为加法、减法等创建运算符按钮示例
- 为等号按钮添加颜色效果以突出显示它
后端实施步骤
- 为每个按钮添加动作
- 在除等于操作之外的每个按钮的操作中，在标签文本中附加相应的数字或运算符
- 在 equals to action 中获取标签的文本并启动 try except 块
- 在 try 块内，对标签文本使用 eval 方法来获取答案并将答案设置为标签
- 在 except 块内将“错误输入”设置为文本
- 对于删除操作，从标签中删除最后一个字符，对于清除操作，将整个文本设置为空白。
下面是实现
# importing libraries
from PyQt5.QtWidgets import *
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys
class Window(QMainWindow):
def __init__(self):
super().__init__()
# setting title
self.setWindowTitle("Python ")
# setting geometry
self.setGeometry(100, 100, 360, 350)
# calling method
self.UiComponents()
# showing all the widgets
self.show()
# method for widgets
def UiComponents(self):
# creating a label
self.label = QLabel(self)
# setting geometry to the label
self.label.setGeometry(5, 5, 350, 70)
# creating label multi line
self.label.setWordWrap(True)
# setting style sheet to the label
self.label.setStyleSheet("QLabel"
"{"
"border : 4px solid black;"
"background : white;"
"}")
# setting alignment to the label
self.label.setAlignment(Qt.AlignRight)
# setting font
self.label.setFont(QFont('Arial', 15))
# adding number button to the screen
# creating a push button
push1 = QPushButton("1", self)
# setting geometry
push1.setGeometry(5, 150, 80, 40)
# creating a push button
push2 = QPushButton("2", self)
# setting geometry
push2.setGeometry(95, 150, 80, 40)
# creating a push button
push3 = QPushButton("3", self)
# setting geometry
push3.setGeometry(185, 150, 80, 40)
# creating a push button
push4 = QPushButton("4", self)
# setting geometry
push4.setGeometry(5, 200, 80, 40)
# creating a push button
push5 = QPushButton("5", self)
# setting geometry
push5.setGeometry(95, 200, 80, 40)
# creating a push button
push6 = QPushButton("5", self)
# setting geometry
push6.setGeometry(185, 200, 80, 40)
# creating a push button
push7 = QPushButton("7", self)
# setting geometry
push7.setGeometry(5, 250, 80, 40)
# creating a push button
push8 = QPushButton("8", self)
# setting geometry
push8.setGeometry(95, 250, 80, 40)
# creating a push button
push9 = QPushButton("9", self)
# setting geometry
push9.setGeometry(185, 250, 80, 40)
# creating a push button
push0 = QPushButton("0", self)
# setting geometry
push0.setGeometry(5, 300, 80, 40)
# adding operator push button
# creating push button
push_equal = QPushButton("=", self)
# setting geometry
push_equal.setGeometry(275, 300, 80, 40)
# adding equal button a color effect
c_effect = QGraphicsColorizeEffect()
c_effect.setColor(Qt.blue)
push_equal.setGraphicsEffect(c_effect)
# creating push button
push_plus = QPushButton("+", self)
# setting geometry
push_plus.setGeometry(275, 250, 80, 40)
# creating push button
push_minus = QPushButton("-", self)
# setting geometry
push_minus.setGeometry(275, 200, 80, 40)
# creating push button
push_mul = QPushButton("*", self)
# setting geometry
push_mul.setGeometry(275, 150, 80, 40)
# creating push button
push_div = QPushButton("/", self)
# setting geometry
push_div.setGeometry(185, 300, 80, 40)
# creating push button
push_point = QPushButton(".", self)
# setting geometry
push_point.setGeometry(95, 300, 80, 40)
# clear button
push_clear = QPushButton("Clear", self)
push_clear.setGeometry(5, 100, 200, 40)
# del one character button
push_del = QPushButton("Del", self)
push_del.setGeometry(210, 100, 145, 40)
# adding action to each of the button
push_minus.clicked.connect(self.action_minus)
push_equal.clicked.connect(self.action_equal)
push0.clicked.connect(self.action0)
push1.clicked.connect(self.action1)
push2.clicked.connect(self.action2)
push3.clicked.connect(self.action3)
push4.clicked.connect(self.action4)
push5.clicked.connect(self.action5)
push6.clicked.connect(self.action6)
push7.clicked.connect(self.action7)
push8.clicked.connect(self.action8)
push9.clicked.connect(self.action9)
push_div.clicked.connect(self.action_div)
push_mul.clicked.connect(self.action_mul)
push_plus.clicked.connect(self.action_plus)
push_point.clicked.connect(self.action_point)
push_clear.clicked.connect(self.action_clear)
push_del.clicked.connect(self.action_del)
def action_equal(self):
# get the label text
equation = self.label.text()
try:
# getting the ans
ans = eval(equation)
# setting text to the label
self.label.setText(str(ans))
except:
# setting text to the label
self.label.setText("Wrong Input")
def action_plus(self):
# appending label text
text = self.label.text()
self.label.setText(text + " + ")
def action_minus(self):
# appending label text
text = self.label.text()
self.label.setText(text + " - ")
def action_div(self):
# appending label text
text = self.label.text()
self.label.setText(text + " / ")
def action_mul(self):
# appending label text
text = self.label.text()
self.label.setText(text + " * ")
def action_point(self):
# appending label text
text = self.label.text()
self.label.setText(text + ".")
def action0(self):
# appending label text
text = self.label.text()
self.label.setText(text + "0")
def action1(self):
# appending label text
text = self.label.text()
self.label.setText(text + "1")
def action2(self):
# appending label text
text = self.label.text()
self.label.setText(text + "2")
def action3(self):
# appending label text
text = self.label.text()
self.label.setText(text + "3")
def action4(self):
# appending label text
text = self.label.text()
self.label.setText(text + "4")
def action5(self):
# appending label text
text = self.label.text()
self.label.setText(text + "5")
def action6(self):
# appending label text
text = self.label.text()
self.label.setText(text + "6")
def action7(self):
# appending label text
text = self.label.text()
self.label.setText(text + "7")
def action8(self):
# appending label text
text = self.label.text()
self.label.setText(text + "8")
def action9(self):
# appending label text
text = self.label.text()
self.label.setText(text + "9")
def action_clear(self):
# clearing the label text
self.label.setText("")
def action_del(self):
# clearing a single digit
text = self.label.text()
print(text[:len(text)-1])
self.label.setText(text[:len(text)-1])
# create pyqt5 app
App = QApplication(sys.argv)
# create the instance of our Window
window = Window()
# start the app
sys.exit(App.exec())
输出 ：