C++ グラフィカル プログラミング インターフェイスを設計するための実践ガイド

#ifndef CALCULATOR_WIDGET_H
#define CALCULATOR_WIDGET_H

#include <QWidget>
#include <QGridLayout>
#include <QPushButton>
#include <QLineEdit>

class CalculatorWidget : public QWidget {
    Q_OBJECT

public:
    CalculatorWidget(QWidget *parent = nullptr);

private slots:
    void numberButtonClicked();
    void operatorButtonClicked();
    void equalsButtonClicked();

private:
    QGridLayout *gridLayout;
    QPushButton *numberButtons[10];
    QPushButton *operatorButtons[4];
    QPushButton *equalsButton;
    QLineEdit *display;
};

#endif // CALCULATOR_WIDGET_H

#include "calculator_widget.h"

CalculatorWidget::CalculatorWidget(QWidget *parent)
    : QWidget(parent)
{
    // 创建布局
    gridLayout = new QGridLayout;
    setLayout(gridLayout);

    // 创建数字按钮
    for (int i = 0; i < 10; i++) {
        numberButtons[i] = new QPushButton(QString::number(i));
        gridLayout->addWidget(numberButtons[i], i / 3, i % 3);
        connect(numberButtons[i], &QPushButton::clicked, this, &CalculatorWidget::numberButtonClicked);
    }

    // 创建运算符按钮
    operatorButtons[0] = new QPushButton("+");
    operatorButtons[1] = new QPushButton("-");
    operatorButtons[2] = new QPushButton("*");
    operatorButtons[3] = new QPushButton("/");
    for (int i = 0; i < 4; i++) {
        gridLayout->addWidget(operatorButtons[i], (i + 1) / 2, 3);
        connect(operatorButtons[i], &QPushButton::clicked, this, &CalculatorWidget::operatorButtonClicked);
    }

    // 创建等号按钮
    equalsButton = new QPushButton("=");
    gridLayout->addWidget(equalsButton, 4, 3);
    connect(equalsButton, &QPushButton::clicked, this, &CalculatorWidget::equalsButtonClicked);

    // 创建显示屏
    display = new QLineEdit;
    gridLayout->addWidget(display, 0, 0, 1, 3);
}

void CalculatorWidget::numberButtonClicked()
{
    QPushButton *button = qobject_cast<QPushButton*>(sender());
    display->setText(display->text() + button->text());
}

void CalculatorWidget::operatorButtonClicked()
{
    QPushButton *button = qobject_cast<QPushButton*>(sender());
    // 保存操作数和运算符
    operator = button->text();
    operand = display->text();
}

void CalculatorWidget::equalsButtonClicked()
{
    // 计算结果
    int result = 0;
    if (operator == "+") {
        result = operand.toInt() + display->text().toInt();
    } else if (operator == "-") {
        result = operand.toInt() - display->text().toInt();
    } else if (operator == "*") {
        result = operand.toInt() * display->text().toInt();
    } else if (operator == "/") {
        result = operand.toInt() / display->text().toInt();
    }
    // 显示结果
    display->setText(QString::number(result));
}

g++ -std=c++11 -I/usr/include/qt5 calculator_widget.cpp -o calculator