qt虚拟键盘代码

以下是一个简单的Qt虚拟键盘的示例代码：

#include <QtWidgets>

class VirtualKeyboard : public QWidget
{
    Q_OBJECT

public:
    VirtualKeyboard(QWidget *parent = nullptr);

private slots:
    void buttonClicked();

private:
    QLineEdit *m_edit;
};

VirtualKeyboard::VirtualKeyboard(QWidget *parent)
    : QWidget(parent)
{
    QVBoxLayout *layout = new QVBoxLayout(this);

    m_edit = new QLineEdit(this);
    layout->addWidget(m_edit);

    QGridLayout *grid = new QGridLayout;
    QStringList keys;
    keys << "7" << "8" << "9" << "/"
         << "4" << "5" << "6" << "*"
         << "1" << "2" << "3" << "-"
         << "0" << "." << "=" << "+";
    int pos = 0;
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            QPushButton *button = new QPushButton(keys[pos], this);
            connect(button, SIGNAL(clicked()), this, SLOT(buttonClicked()));
            grid->addWidget(button, i, j);
            ++pos;
        }
    }
    layout->addLayout(grid);
}

void VirtualKeyboard::buttonClicked()
{
    QPushButton *button = qobject_cast<QPushButton *>(sender());
    if (button) {
        QString text = button->text();
        if (text == "=") {
            m_edit->setText(QString::number(eval(m_edit->text())));
        } else if (text == "C") {
            m_edit->clear();
        } else {
            m_edit->setText(m_edit->text() + text);
        }
    }
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    VirtualKeyboard keyboard;
    keyboard.show();
    return app.exec();
}

该示例中，我们创建了一个VirtualKeyboard类，它继承自QWidget类，并包含一个QLineEdit和一个QGridLayout，用于显示虚拟键盘按钮。在构造函数中，我们使用QVBoxLayout和QGridLayout布局管理器来设置虚拟键盘的布局。在buttonClicked()槽函数中，我们根据按钮的文本来执行相应的操作，例如将文本添加到QLineEdit中，或者清空QLineEdit中的文本。最后，我们在main()函数中创建了一个VirtualKeyboard对象，并将其显示出来。