一、效果图

二、代码

#include "verticallayoutwidget.h"
#include "ui_verticallayoutwidget.h"

VerticalLayoutWidget::VerticalLayoutWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::VerticalLayoutWidget)
{
    ui->setupUi(this);
    for(int i=0;i<3;i++){
        QLabel *label = new QLabel;
        label->setStyleSheet("background:white");
        label->setText("label"+QString::number(i));
        ui->verticalLayout->addWidget(label);
    }
}

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

void VerticalLayoutWidget::on_pushButton_clicked()
{
    QLayoutItem *child;
    while ((child = ui->verticalLayout->itemAt(0)) != nullptr) {
        ui->verticalLayout->removeItem(child);
        delete child->widget();
        delete child;
        child = nullptr;
    }
}

三、总结
1.ui->verticalLayout->removeItem(child);只是将控件从布局管理器里移除，此时控件依然会在界面显示
2.delete child->widget();将对象销毁才可以使得控件不在界面展示