核心思想是：

在main中引入QMainWindow对象，将qml文件作为该对象的widget，并将该对象注册到qml中，然后再qml中通过识别鼠标的位移来更改这个mainwindow的pos属性。

实现：

#include 
     
      #include 
      
       #include 
       
        #include 
        
                                 int main(int argc, char *argv[]){    QApplication app(argc, argv);                            QMainWindow window;                            QDeclarativeView* v = new QDeclarativeView;    window.setCentralWidget(v);                            v->setSource(QUrl::fromLocalFile(("draw_rectangles.qml")));                              // expose window object to QML    v->rootContext()->setContextProperty("mainwindow",&window);                            window.setStyleSheet("background:transparent;");    window.setAttribute(Qt::WA_TranslucentBackground);    window.setWindowFlags(Qt::FramelessWindowHint);    window.show();                            app.exec();}
        
       
      
     

   qml：

Item {                   Rectangle {             color: "blue"             x: 50; y: 50; width: 100; height: 100                MouseArea {                id: mouseRegion                anchors.fill: parent;                property variant clickPos: "1,1"                    onPressed: {                    clickPos  = Qt.point(mouse.x,mouse.y)                }                    onPositionChanged: {                    var delta = Qt.point(mouse.x-clickPos.x, mouse.y-clickPos.y)                    mainwindow.pos = Qt.point(mainwindow.pos.x+delta.x,                                      mainwindow.pos.y+delta.y)                }            } //mousearea         } //rectangle }

转载：http://blog.csdn.net/sgnh123456/article/details/8055654