用QT+vs混合编程用插模机制实现简易计算器的案例

好的，这是一个用QT+VS混合编程，使用插模机制实现的简易计算器案例：

1. 首先，在QT中创建一个新的工程（例如，命名为Calculator），选择“QT Widgets Application”。

2. 在VS中打开Calculator.pro文件，将以下代码添加到文件末尾：

win32:CONFIG(release, debug|release): LIBS += -L$$PWD/ -lCalculator
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/ -lCalculatord

3. 在VS中新建一个工程（例如，命名为CalculatorDLL），选择“DLL”模板。

4. 将以下代码添加到CalculatorDLL.h文件中：

#ifndef CALCULATORDLL_H
#define CALCULATORDLL_H

#include <QtCore/qglobal.h>
#include <QtPlugin>

class CalculatorDLL
{
public:
    virtual double add(double a, double b) = 0;
    virtual double subtract(double a, double b) = 0;
    virtual double multiply(double a, double b) = 0;
    virtual double divide(double a, double b) = 0;
};

Q_DECLARE_INTERFACE(CalculatorDLL, "com.example.CalculatorDLL/1.0")

#endif // CALCULATORDLL_H

5. 在CalculatorDLL.cpp中，将以下代码添加到文件末尾：

#include "CalculatorDLL.h"

class CalculatorPlugin : public CalculatorDLL
{
public:
    double add(double a, double b) override
    {
        return a + b;
    }

    double subtract(double a, double b) override
    {
        return a - b;
    }

    double multiply(double a, double b) override
    {
        return a * b;
    }

    double divide(double a, double b) override
    {
        return a / b;
    }
};

Q_EXPORT_PLUGIN2(CalculatorPlugin, CalculatorDLL)

6. 在QT中打开Calculator.cpp文件，将以下代码添加到文件末尾：

#include "CalculatorDLL.h"

void Calculator::loadPlugins()
{
    QDir pluginsDir(qApp->applicationDirPath());
    pluginsDir.cd("plugins");

    foreach (QString fileName, pluginsDir.entryList(QDir::Files))
    {
        QPluginLoader pluginLoader(pluginsDir.absoluteFilePath(fileName));
        QObject *plugin = pluginLoader.instance();

        if (plugin)
        {
            CalculatorDLL *calculator = qobject_cast<CalculatorDLL *>(plugin);
            if (calculator)
            {
                m_calculators.append(calculator);
            }
        }
    }
}

void Calculator::unloadPlugins()
{
    foreach (CalculatorDLL *calculator, m_calculators)
    {
        delete calculator;
    }

    m_calculators.clear();
}

void Calculator::on_addBtn_clicked()
{
    double a = ui->num1Edit->text().toDouble();
    double b = ui->num2Edit->text().toDouble();
    double result = 0;

    foreach (CalculatorDLL *calculator, m_calculators)
    {
        result += calculator->add(a, b);
    }

    ui->resultLabel->setText(QString::number(result));
}

void Calculator::on_subtractBtn_clicked()
{
    double a = ui->num1Edit->text().toDouble();
    double b = ui->num2Edit->text().toDouble();
    double result = 0;

    foreach (CalculatorDLL *calculator, m_calculators)
    {
        result += calculator->subtract(a, b);
    }

    ui->resultLabel->setText(QString::number(result));
}

void Calculator::on_multiplyBtn_clicked()
{
    double a = ui->num1Edit->text().toDouble();
    double b = ui->num2Edit->text().toDouble();
    double result = 0;

    foreach (CalculatorDLL *calculator, m_calculators)
    {
        result += calculator->multiply(a, b);
    }

    ui->resultLabel->setText(QString::number(result));
}

void Calculator::on_divideBtn_clicked()
{
    double a = ui->num1Edit->text().toDouble();
    double b = ui->num2Edit->text().toDouble();
    double result = 0;

    foreach (CalculatorDLL *calculator, m_calculators)
    {
        result += calculator->divide(a, b);
    }

    ui->resultLabel->setText(QString::number(result));
}

7. 在QT中打开Calculator.h文件，将以下代码添加到文件末尾：

#include <QtCore/QDir>
#include <QtCore/QPluginLoader>
#include <QtCore/QList>
#include "CalculatorDLL.h"

class Calculator : public QMainWindow
{
    Q_OBJECT

public:
    void loadPlugins();
    void unloadPlugins();

private slots:
    void on_addBtn_clicked();
    void on_subtractBtn_clicked();
    void on_multiplyBtn_clicked();
    void on_divideBtn_clicked();

private:
    Ui::CalculatorClass ui;
    QList<CalculatorDLL *> m_calculators;
};

8. 在QT中打开Calculator.ui文件，添加4个QPushButton和2个QLineEdit，分别命名为addBtn、subtractBtn、multiplyBtn、divideBtn、num1Edit、num2Edit和resultLabel。

9. 在QT中打开Calculator.pro文件，将以下代码添加到文件末尾：

TARGET = Calculator
TEMPLATE = app
DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += main.cpp\
        Calculator.cpp
HEADERS  += Calculator.h
FORMS    += Calculator.ui
CONFIG += plugin
PLUGIN_SUFFIX = .dll
PLUGIN_DESTINATION = plugins

10. 在VS中打开CalculatorDLL的属性页，选择“配置属性”->“常规”，将输出目录设置为Calculator工程的plugins目录。

11. 在VS中打开CalculatorDLL的属性页，选择“配置属性”->“C/C++”->“代码生成”，将运行库设置为“多线程DLL (/MD)”。

12. 编译并运行程序，即可使用简易计算器。可以在CalculatorDLL工程中添加新的插件实现不同的计算方式，并在运行时动态加载。