qt中拖动窗口widget

提要

继承与QDialog的窗口，窗口原本按住标题栏可以拖动窗口，但是设置了窗口的隐藏标题栏属性后，窗口不再能够拖动。或者继承于QWidget的窗体，不具有窗口拖动功能。
本文实现继承于窗口widget或者继承于QDialog隐藏窗口标题栏的窗口鼠标按下后不放可以拖动，鼠标释放后停止拖动。要想实现这样的功能继承于QWidget的窗体需要重写鼠标按下，移动，释放事件。继承于QDialog窗口但是隐藏窗体标题栏的也是一样的，需重写上面的三个方法。

示例

namedialog.h

#ifndef NAMEDIALOG_H
#define NAMEDIALOG_H#include <QDialog>/******类功能描述：设置大屏列表的名称*****/
namespace Ui {
class NameDialog;
}class NameDialog : public QDialog
{Q_OBJECTpublic:explicit NameDialog(QWidget *parent = nullptr);~NameDialog();
protected:void mousePressEvent(QMouseEvent *event);//鼠标点击void mouseMoveEvent(QMouseEvent *event);//鼠标移动事件void mouseReleaseEvent(QMouseEvent *event);//鼠标释放事件
private:Ui::NameDialog *ui;QPoint          m_offPos;//鼠标点击点与窗口左上角的距离
};#endif // NAMEDIALOG_H

namedialog.cpp

#include "namedialog.h"
#include "ui_namedialog.h"
#include <QMouseEvent>NameDialog::NameDialog(QWidget *parent) :QDialog(parent),ui(new Ui::NameDialog)
{ui->setupUi(this);setWindowFlag(Qt::FramelessWindowHint);
}NameDialog::~NameDialog()
{delete ui;
}void NameDialog::mousePressEvent(QMouseEvent *event)
{if (event->button() == Qt::LeftButton) {QPoint startPos = event->globalPos();m_offPos = startPos - geometry().topLeft();}QDialog::mousePressEvent(event);
}void NameDialog::mouseMoveEvent(QMouseEvent *event)
{if (event->buttons() == Qt::LeftButton) {QPoint endPos = event->globalPos();move(endPos - m_offPos);}QDialog::mouseMoveEvent(event);
}void NameDialog::mouseReleaseEvent(QMouseEvent *event)
{QDialog::mouseReleaseEvent(event);
}

以上重写鼠标按下，移动和释放事件便可以实现窗体的按下拖动。如果是继承于QWidget窗体，则基类为QWidget，相应的在继承于QWidget的类中实现鼠标的点击，移动和释放事件，函数的实现几乎一样，唯一不一样的是，调用父类的点击，移动和释放事件，将QDialog::mousePressEvent(event);改为QWidget::mousePressEvent(event);依次类推，如下。

#ifndef NAMEDIALOG_H
#define NAMEDIALOG_H#include <QDialog>/******类功能描述：设置大屏列表的名称*****/
namespace Ui {
class NameWidget;
}class NameWidget: public QWidget
{Q_OBJECTpublic:explicit NameWidget(QWidget *parent = nullptr);~NameWidget();
protected:void mousePressEvent(QMouseEvent *event);//鼠标点击void mouseMoveEvent(QMouseEvent *event);//鼠标移动事件void mouseReleaseEvent(QMouseEvent *event);//鼠标释放事件
private:Ui::NameWidget*ui;QPoint          m_offPos;//鼠标点击点与窗口左上角的距离
};#endif // NAMEDIALOG_H

#include "namewidget.h"
#include "ui_namewidget.h"
#include <QMouseEvent>NameWidget::NameWidget(QWidget *parent) :QWidget(parent),ui(new Ui::NameWidget)
{ui->setupUi(this);setWindowFlag(Qt::FramelessWindowHint);
}NameWidget::~NameWidget()
{delete ui;
}
void NameWidget::mousePressEvent(QMouseEvent *event)
{if (event->button() == Qt::LeftButton) {QPoint startPos = event->globalPos();m_offPos = startPos - geometry().topLeft();}QWidget::mousePressEvent(event);
}void NameWidget::mouseMoveEvent(QMouseEvent *event)
{if (event->buttons() == Qt::LeftButton) {QPoint endPos = event->globalPos();move(endPos - m_offPos);}QWidget::mouseMoveEvent(event);
}void NameWidget::mouseReleaseEvent(QMouseEvent *event)
{QWidget::mouseReleaseEvent(event);
}