1.传参
用指针
MainWindow w;
QPushButton * pushButton1 = new QPushButton(&w);
pushButton1->move(100,100);
pushButton1->show();
用实例
QPushButton b1(&w) ;
2.setParent(&parentt);
QPushButton b1() ;
b1.resize(10,10);
b1.setParent(&w);