参数是从信号传到 槽函数里.举个例子:
class MyBtn : public QPushButton
{
public:
        MyBtn(QWidget* parent = 0):QPushButton(parent)
        {
            connect(this,SIGNAL(clicked()),this,SLOT(clickSlot());
        }
signals:
        void transferText(QString text);
private slots:
       void clickSlot()
       {
            emit transferText(this->text());
       }
};
然后在别的地方connect(myBtn,SIGNAL(transferText(QString),this,SLOT(testSlot(QString)));