QSpinBox *spinBox=new QSpinBox; 
QSlider *slider =new QSlider; 
spinBox->setRange(0,20); 
slider->setRange(0,20); 
QObject::connect(spinBox, SIGNAL(valueChanged(int)),slider, SLOT(setValue(int))); 
QObject::connect(slider, SIGNAL(valueChanged(int)),spinBox, SLOT(setValue(int))); 
slider->setValue(10); 
程序片段如上。怎么不能初始化,信号和槽也关联不上。 
求解!!!