Qt无边框窗口拖拽和阴影的实现方法

this->setWindowFlags(Qt::FramelessWindowHint);

 void Widget::mouseMoveEvent(QMouseEvent *event)
 {
  QPoint y = event->globalPos();//鼠标相当于桌面左上角的位置，鼠标全局位置
  QPoint x = y - this->z;
  this->move(x);
 }
 ​
 void Widget::mousePressEvent(QMouseEvent *event)
 {
  QPoint y = event->globalPos();//鼠标相当于桌面左上角的位置，鼠标全局位置
  QPoint x = this->geometry().topLeft();//窗口左上角位于桌面左上角的位置，窗口位置
  this->z = y - x; //定值，不变
 }
 ​
 void Widget::mouseReleaseEvent(QMouseEvent *event)
 {
  this->z = QPoint(); //鼠标松开获取当前的坐标
 }

 #include "widget.h"
 #include <QApplication>
 ​
 int main(int argc, char *argv[])
 {
 QApplication a(argc, argv);
 Widget w;
 w.show();
 ​
 return a.exec();
 }

 #include "widget.h"
 #include "ui_widget.h"
 #include <QMouseEvent>
 #include <QWidget>
 #include <QGraphicsDropShadowEffect>
 ​
 Widget::Widget(QWidget *parent) :
 QWidget(parent),
 ui(new Ui::Widget)
 {
 ui->setupUi(this);
 ​
 this->setWindowFlags(Qt::FramelessWindowHint);
 ​
 QGraphicsDropShadowEffect *shadow = new QGraphicsDropShadowEffect();
 ​
 shadow->setBlurRadius(5); //边框圆角
 shadow->setColor(Qt::black);//边框颜色
 shadow->setOffset(0);  //不偏移
 ​
 ui->shadowWidget->setGraphicsEffect(shadow);
 ​
 this->setAttribute(Qt::WA_TranslucentBackground); //父窗口设置透明，只留下子窗口
 }
 ​
 Widget::~Widget()
 {
 delete ui;
 }
 ​
 void Widget::mouseMoveEvent(QMouseEvent *event)
 {
 QPoint y = event->globalPos();//鼠标相当于桌面左上角的位置，鼠标全局位置
 QPoint x = y - this->z;
 this->move(x);
 }
 ​
 void Widget::mousePressEvent(QMouseEvent *event)
 {
 QPoint y = event->globalPos();//鼠标相当于桌面左上角的位置，鼠标全局位置
 QPoint x = this->geometry().topLeft();//窗口左上角位于桌面左上角的位置，窗口位置
 this->z = y - x; //定值，不变
 }
 ​
 void Widget::mouseReleaseEvent(QMouseEvent *event)
 {
 this->z = QPoint(); //鼠标松开获取当前的坐标
 }

 #ifndef WIDGET_H
 #define WIDGET_H
 ​
 #include <QWidget>
 ​
 namespace Ui {
 class Widget;
 }
 ​
 class Widget : public QWidget
 {
 Q_OBJECT
 ​
 public:
 explicit Widget(QWidget *parent = 0);
 ~Widget();
 ​
 virtual void mouseMoveEvent(QMouseEvent *event);
 virtual void mousePressEvent(QMouseEvent *event);
 virtual void mouseReleaseEvent(QMouseEvent *event);
 ​
 private:
 Ui::Widget *ui;
 QPoint z;
 };
 ​
 #endif // WIDGET_H