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 }