QDesktopServices::openUrl這個是個神器，通過URL可以開啟本地的資料夾或某一個web網站

還是截張圖把：

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

public slots:
    void openFileBtnClicked();
    void openWebBtnClicked();

protected:
    void OpenUrl(QString str);

private:
    Ui::Widget *ui;
};

#endif // WIDGET_H
 

main.cpp

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QUrl>
#include <QDesktopServices>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    connect(ui->openFilePpushButton,SIGNAL(clicked(bool)),this,SLOT(openFileBtnClicked()));
    connect(ui->openWebPushButton,SIGNAL(clicked(bool)),this,SLOT(openWebBtnClicked()));
}

Widget::~Widget()
{
    delete ui;
}

void Widget::openFileBtnClicked()
{
    //open the disk "C"
    //OpenUrl("C:/"); you can write it in this way or in the following way
    OpenUrl("file:///C:/");
}

void Widget::openWebBtnClicked()
{
    OpenUrl("https://www.baidu.com");
}

void Widget::OpenUrl(QString str)
{
    QDesktopServices::openUrl(QUrl(str));
}