只有QLabel 标签对象才可以有伙伴窗口对象，也只有该QLabel对象具有快捷键。
快捷键设置方法：在显示文本的某个字符的前面加一个前缀“&” 就可以定义快捷键了
1 Dialog::Dialog(QWidget *parent) 2 : QDialog(parent) 3 { 4 label1 = new QLabel(this); 5 label1->setText(tr("请输入圆的半径： ")); 6 lineEdit = new QLineEdit(this); 7 label2 = new QLabel(this); 8 button = new QPushButton(this); 9 button->setText(tr("显示对应的圆面积")); 10 11 nameLabel = new QLabel("&Name",this); 12 nameEdit = new QLineEdit(this); 13 nameLabel->setBuddy(nameEdit); 14 15 phoneLabel = new QLabel("&Phone",this); 16 phoneEdit = new QLineEdit(this); 17 phoneLabel->setBuddy(phoneEdit); 18 19 QGridLayout * mainLayout = new QGridLayout(this); 20 mainLayout->addWidget(label1,0,0); 21 mainLayout->addWidget(lineEdit,0,1); 22 mainLayout->addWidget(label2,1,0); 23 mainLayout->addWidget(button,1,1); 24 25 mainLayout->addWidget(nameLabel,2,0); 26 mainLayout->addWidget(nameEdit,2,1); 27 mainLayout->addWidget(phoneLabel,3,0); 28 mainLayout->addWidget(phoneEdit,3,1); 29 30 connect(button,SIGNAL(clicked()),this,SLOT(showArea())); 31 }