Qt QGridLayout元素的宽度和高度相同，

#include <QtWidgets>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QWidget window;
    QGridLayout *layout = new QGridLayout(&window);

    // 创建四个按钮
    QPushButton *button1 = new QPushButton("Button 1");
    QPushButton *button2 = new QPushButton("Button 2");
    QPushButton *button3 = new QPushButton("Button 3");
    QPushButton *button4 = new QPushButton("Button 4");

    // 设置行和列的拉伸因子为1，使它们的宽度和高度相同
    layout->setRowStretch(0, 1);
    layout->setRowStretch(1, 1);
    layout->setColumnStretch(0, 1);
    layout->setColumnStretch(1, 1);

    // 将按钮添加到布局中
    layout->addWidget(button1, 0, 0);
    layout->addWidget(button2, 0, 1);
    layout->addWidget(button3, 1, 0);
    layout->addWidget(button4, 1, 1);

    window.show();

    return app.exec();
}