Python使用PyQt开发一个桌面计算器的实战指南

pip install PyQt5

pyqt_calculator/
│
├── main.py              # 主程序入口
├── calculator.ui        # Qt Designer 设计文件（可选）
└── ui_calculator.py     # UI 转换后的 Python 文件

# main.py
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QPushButton, QLineEdit, QVBoxLayout
from PyQt5.QtCore import Qt
import sys


class Calculator(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("PyQt 计算器")
        self.setFixedSize(300, 400)
        self.init_ui()

    def init_ui(self):
        # 显示区域
        self.display = QLineEdit()
        self.display.setAlignment(Qt.AlignRight)
        self.display.setReadOnly(True)
        self.display.setStyleSheet("font-size: 24px; padding: 10px;")

        # 按钮布局
        buttons = {
            '7': (0, 0), '8': (0, 1), '9': (0, 2), '/': (0, 3),
            '4': (1, 0), '5': (1, 1), '6': (1, 2), '*': (1, 3),
            '1': (2, 0), '2': (2, 1), '3': (2, 2), '-': (2, 3),
            '0': (3, 0), '.': (3, 1), 'C': (3, 2), '+': (3, 3),
            '=': (4, 0, 1, 4)
        }

        grid = QGridLayout()
        for text, pos in buttons.items():
            button = QPushButton(text)
            button.setStyleSheet("font-size: 20px; height: 50px;")
            if len(pos) == 2:
                grid.addWidget(button, pos[0], pos[1])
            else:
                grid.addWidget(button, pos[0], pos[1], pos[2], pos[3])
            button.clicked.connect(self.on_button_clicked)

        layout = QVBoxLayout()
        layout.addWidget(self.display)
        layout.addLayout(grid)
        self.setLayout(layout)

    def on_button_clicked(self):
        sender = self.sender().text()
        current = self.display.text()

        if sender == "C":
            self.display.clear()
        elif sender == "=":
            try:
                result = str(eval(current))
                self.display.setText(result)
            except Exception:
                self.display.setText("Error")
        else:
            self.display.setText(current + sender)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Calculator()
    window.show()
    sys.exit(app.exec_())

def keyPressEvent(self, event):
    key = event.key()
    if key == Qt.Key_Return or key == Qt.Key_Enter:
        self.on_button_clicked()  # 模拟 "="
    elif key == Qt.Key_Backspace:
        self.display.setText(self.display.text()[:-1])
    else:
        text = event.text()
        if text.isdigit() or text in ['+', '-', '*', '/', '.']:
            self.display.setText(self.display.text() + text)

import ast
import operator as op

operators = {
    ast.Add: op.add,
    ast.Sub: op.sub,
    ast.Mult: op.mul,
    ast.Div: op.truediv
}

def safe_eval(expr):
    node = ast.parse(expr, mode='eval').body
    def _eval(node):
        if isinstance(node, ast.Num):
            return node.n
        elif isinstance(node, ast.BinOp):
            return operators[type(node.op)](_eval(node.left), _eval(node.right))
        else:
            raise TypeError(node)
    return _eval(node)

self.setStyleSheet("""
    QWidget {
        background-color: #2E3440;
    }
    QLineEdit {
        background: #3B4252;
        color: #ECEFF4;
        border: none;
        border-radius: 5px;
    }
    QPushButton {
        background-color: #4C566A;
        color: #ECEFF4;
        border-radius: 8px;
    }
    QPushButton:hover {
        background-color: #5E81AC;
    }
    QPushButton:pressed {
        background-color: #81A1C1;
    }
""")

pip install pyinstaller
pyinstaller -F -w main.py