Qt 无边框

#ifndef FRAMELESSWINDOW_H
#define FRAMELESSWINDOW_H

#include <QtGui/QWidget>
#include "ui_framelesswindow.h"

class QMouseEvent;

class framelessWindow : public QWidget
{
	Q_OBJECT

public:
	framelessWindow(QWidget *parent = 0, Qt::WFlags flags = 0);
	~framelessWindow();

private:
	Ui::framelessWindowClass ui;

	void mousePressEvent(QMouseEvent *event) override;
	void mouseMoveEvent(QMouseEvent *event) override;
	void mouseReleaseEvent(QMouseEvent *event) override;

	bool mIsPressed;
	QPoint mVectorDiff;
};

#endif // FRAMELESSWINDOW_H

#include "framelesswindow.h"
#include <QMouseEvent>

framelessWindow::framelessWindow(QWidget *parent, Qt::WFlags flags)
	: QWidget(parent, flags)
	, mIsPressed(false)
{
	ui.setupUi(this);
	setWindowFlags(Qt::FramelessWindowHint | Qt::WindowMinimizeButtonHint);
}

framelessWindow::~framelessWindow()
{

}

void framelessWindow::mousePressEvent(QMouseEvent *event)
{

	mIsPressed = true;

	// event->globalPos()：向量，从屏幕左上到鼠标
	// this->pos()：向量，从屏幕左上到程序左上
	// mVectorDiff：向量差
	mVectorDiff = event->globalPos() - this->pos();

}

void framelessWindow::mouseMoveEvent(QMouseEvent *event)
{
	if (mIsPressed)
	{
		// 鼠标在程序中的坐标不变，即向量差不变
		QPoint targetPoint = event->globalPos() - mVectorDiff;
		move(targetPoint);
	}
}

void framelessWindow::mouseReleaseEvent(QMouseEvent *event)
{
	mIsPressed = false;
}