自定义QTreeview和QFileSystemModel，实现时在单独的线程使用定时器每隔500毫秒扫描100文件逐步构建整个模型，并显示在自定义QTreeview上,使用C++给出完整代码

以下是使用定时器和单独线程构建QFileSystemModel并显示在自定义QTreeView上的C++代码示例：

#include <QtWidgets>
#include <QFileSystemModel>

class CustomTreeView : public QTreeView
{
    Q_OBJECT

public:
    CustomTreeView(QWidget *parent = nullptr) : QTreeView(parent) {}
    ~CustomTreeView() {}

    void setModel(QAbstractItemModel *model) override
    {
        QTreeView::setModel(model);
        expandAll();
    }
};

class FileSystemModelThread : public QThread
{
    Q_OBJECT

public:
    FileSystemModelThread(QObject *parent = nullptr)
        : QThread(parent), m_model(nullptr) {}

    ~FileSystemModelThread() {}

    void setRootPath(const QString &path)
    {
        m_rootPath = path;
    }

    QFileSystemModel* model()
    {
        return m_model;
    }

signals:
    void modelReady(QAbstractItemModel *model);

protected:
    void run() override
    {
        m_model = new QFileSystemModel();
        m_model->setRootPath(m_rootPath);

        QTimer timer;
        timer.setInterval(500);

        int row = 0;
        QModelIndex parentIndex = QModelIndex();
        while (m_model->canFetchMore(parentIndex))
        {
            m_model->fetchMore(parentIndex);
            row += 100;

            QModelIndex index = m_model->index(row, 0, parentIndex);
            if (!index.isValid())
            {
                continue;
            }

            CustomTreeView *treeView = qobject_cast<CustomTreeView*>(parent());
            if (treeView)
            {
                QAbstractItemModel *model = m_model->takeColumn(0, parentIndex);
                emit modelReady(model);
            }

            QEventLoop loop;
            connect(&timer, &QTimer::timeout, &loop, &QEventLoop::quit);
            timer.start();
            loop.exec();
        }
    }

private:
    QString m_rootPath;
    QFileSystemModel *m_model;
};

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr)
        : QMainWindow(parent), m_fileSystemModelThread(nullptr)
    {
        QWidget *centralWidget = new QWidget(this);
        QVBoxLayout *layout = new QVBoxLayout(centralWidget);
        setCentralWidget(centralWidget);

        m_treeView = new CustomTreeView(centralWidget);
        layout->addWidget(m_treeView);

        QPushButton *button = new QPushButton("Start", centralWidget);
        layout->addWidget(button);

        connect(button, &QPushButton::clicked, this, &MainWindow::startFileSystemModelThread);
    }

    ~MainWindow() {}

private slots:
    void modelReady(QAbstractItemModel *model)
    {
        m_treeView->setModel(model);
    }

private:
    void startFileSystemModelThread()
    {
        if (m_fileSystemModelThread)
        {
            return;
        }

        m_fileSystemModelThread = new FileSystemModelThread(this);
        m_fileSystemModelThread->setRootPath(QDir::currentPath());
        connect(m_fileSystemModelThread, &FileSystemModelThread::modelReady, this, &MainWindow::modelReady);
        m_fileSystemModelThread->start();
    }

private:
    CustomTreeView *m_treeView;
    FileSystemModelThread *m_fileSystemModelThread;
};

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

    MainWindow mainWindow;
    mainWindow.show();

    return app.exec();
}

#include "main.moc"

在这个示例中，我们创建了一个CustomTreeView类，用于设置模型并展开所有节点。我们还创建了一个FileSystemModelThread类，用于在单独的线程中构建QFileSystemModel，并使用定时器每隔500毫秒扫描100个文件。在构建每个文件夹的子项后，我们将模型发送到MainWindow类的槽中，该槽将模型设置为CustomTreeView的模型。最后，我们在MainWindow类中创建了一个QPushButton，用于启动FileSystemModelThread类的实例。

请注意，此代码示例仅用于演示目的，实际生产代码需要处理线程和模型的更多细节，例如取消线程和处理模型变化的方式。