qt使用定时伸缩QWidget

#ifndef FOLDWIDGET_H
#define FOLDWIDGET_H

#include <QWidget>
#include<QTimer>
namespace Ui {
class FoldWidget;
}

class FoldWidget : public QWidget
{
    Q_OBJECT

public:
    explicit FoldWidget(QWidget *parent = nullptr);
    ~FoldWidget();

private slots:
    void on_pushButton_clicked();

private:
    QTimer *timer;
    Ui::FoldWidget *ui;
};

#endif // FOLDWIDGET_H

#include "foldwidget.h"
#include "ui_foldwidget.h"

FoldWidget::FoldWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::FoldWidget)
{
    ui->setupUi(this);


    ui->widget->setStyleSheet(QString::fromUtf8("#widget{border:1px solid red}"));
    ui->widget->move(ui->pushButton->pos().x(),
                     ui->pushButton->pos().y()+ui->pushButton->height());
    ui->widget->resize(ui-&g