Qt全屏显示和按键ESC退出全屏

1.需求描述

将播放窗口全屏显示，将工具栏边框等隐藏在后面；然后退出全屏通过ESC返回按钮；

2.实现方法

定义一个全屏的容器类，继承于QWidget；全屏时，去掉窗口的父窗口，然后全屏显示，不去掉父窗口指针无法全屏；按下ESC按钮后，通过keyPressEvent(QKeyEvent* pEvent);函数，将父窗口重新设置回去；

#ifndef FULLSCREEN_H
#define FULLSCREEN_H

#include <QWidget>
#include <QKeyEvent>
class FullScreen : public QWidget
{
    Q_OBJECT

public:
    FullScreen(QWidget *parent);
    ~FullScreen();
    void SetFullScreen();
    void keyPressEvent(QKeyEvent* pEvent);
private:
    QWidget* parentwidget=NULL;
};

#endif // FULLSCREEN_H

#include "FullScreen.h"
#include <QLayout>
FullScreen::FullScreen(QWidget *parent)
    : QWidget(parent)
{

}

FullScreen::~FullScreen()
{

}

void FullScreen::SetFullScreen()
{
    parentwidget = parentWidget();
    parentWidget()->layout()->removeWidget(this);
    setParent(NULL);
    showFullScreen();
    raise();
}

void FullScreen::keyPressEvent(QKeyEvent* pEvent)
{
    if (!pEvent->modifiers())
    {
        if (pEvent->key() == Qt::Key_Escape &&isFullScreen())
        {
            hide();//避免一闪而过
            showNormal();
            setParent(parentwidget);
            parentwidget->layout()->addWidget(this);
            show();
            pEvent->accept();
            return;
        }
    }
    QWidget::keyPressEvent(pEvent);
}