效果如下：
做项目中为了美观，经常需要对窗口标题栏，按钮进行自定义，因此常使用隐藏系统默认窗口边框选项 Qt::FramelessWindowHint，为使窗口能被随意拖动，使用Qt中的事件过滤器，重载eventFilter(QObject *obj, QEvent *evt)函数，每次拖拽事件发生时，返回当前事件触发窗体QObject进入事件过滤事件中，并对该窗体位置进行改变。
拖拽事件过滤在主函数中进行加载。每个需要支持拖拽的窗口设置自定义属性：this->setProperty("canMove",true);当属性canMove为真时支持拖拽。即在Main函数中加载过滤后不需要在窗体代码中引用拖拽模块。
窗体可拖拽功能模块代码：
appmove.h
#ifndef APPMOVE_H
#define APPMOVE_H
#include <QObject>
#include <QMutex>
#include <QEvent>
#include <QWidget>
#include <QApplication>
#include <QMouseEvent>
class AppMove:public QObject
{
public:
public:
explicit AppMove(QObject *parent = 0);
void start();
protected:
bool eventFilter(QObject *obj, QEvent *evt);
};
#endif // APPMOVE_H
appmove.cpp
#include "appmove.h"
AppMove::AppMove(QObject *parent) : QObject(parent)
{
}
bool AppMove::eventFilter(QObject *obj, QEvent *evt)
{
QWidget *w = (QWidget *)obj;
if (!w->property("canMove").toBool()) {
return QObject::eventFilter(obj, evt);
}
static QPoint mousePoint;
static bool mousePressed = false;
QMouseEvent *event = static_cast<QMouseEvent *>(evt);
if (event->type() == QEvent::MouseButtonPress) {
if (event->button() == Qt::LeftButton) {
mousePressed = true;
mousePoint = event->globalPos() - w->pos();
return true;
}
} else if (event->type() == QEvent::MouseButtonRelease) {
mousePressed = false;
return true;
} else if (event->type() == QEvent::MouseMove) {
if (mousePressed && (event->buttons() && Qt::LeftButton)) {
w->move(event->globalPos() - mousePoint);
return true;
}
}
return QObject::eventFilter(obj, evt);
}
void AppMove::start()
{
qApp->installEventFilter(this);
}
主函数main:
#include "widget.h"
#include "appmove.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
AppMove move;
move.start();
Widget w;
w.show();
return a.exec();
}
DEMO下载地址：
