例1：

 

QSignMapper *mapper = new QSignMapper(this)

QPushButton *btn1 = new QPushButton(this);

btn1->setText("btn1");

QPushButton *btn2 = new QPushButton(this);

btn2->setText("btn2");

mapper->setMapping(btn1,btn1->text());

mapper->setMapping(btn2,btn2->text());

connect(btn1,SIGNAL(clicked()),mapper,SLOT(map()));

connect(btn2,SIGNAL(clicked()),mapper,SLOT(map()));

connect(mapper,SIGNAL(map(QString),this,SLOT(disStr(QString)));

 整体的作用是通过一个无参的信号转化成有参的信号，然后传给槽函数进行操作

引自：http://blog.csdn.net/hsl17/article/details/6768322

 

例2：

       今天想自己用Qt编一个Ubuntu下简易的计算器，设想每次按下一个数字键或者运算符，输出界面上都会显示各自数字或字符。

当多个signal连接到一个同一个slot，而且slot对每个signal处理不同时，用到QSignalMapper：

The  QSignalMapper   class is provided for situations where many signals are connected to the same slot and the slot needs to handle each signal differently.

代码结构如下：

//声明用于显示所按下数字的lineEdit以及各个按钮

QLineEdit* lineEdit = new QLineEdit("0");

lineEdit->setAlignment(Qt::AlignRight);

QPushButton* pushButton = new QPushButton[20];

pushButton[12].setText("1");

pushButton[13].setText("2");

pushButton[14].setText("3");

pushButton[15].setText("-");

......

QSignalMapper* signalMapper = new QSignalMapper;

......

signalMapper->setMapping(&pushButton[12], QString("1"));

signalMapper->setMapping(&pushButton[13], QString("2"));

signalMapper->setMapping(&pushButton[14], QString("3"));

signalMapper->setMapping(&pushButton[15], QString("-"));

......

connect(&pushButton[12], SIGNAL(clicked()),signalMapper, SLOT (map()));

connect(&pushButton[13], SIGNAL(clicked()),signalMapper, SLOT (map()));

connect(&pushButton[14], SIGNAL(clicked()),signalMapper, SLOT (map()));

connect(&pushButton[15], SIGNAL(clicked()),signalMapper, SLOT (map()));

......

connect(signalMapper, SIGNAL(mapped(const QString &)),this, SLOT(setNum(const QString &)));

引自：http://blog.sina.com.cn/s/blog_5e42f31a0100ykaz.html

转自：http://blog.csdn.net/zzwdkxx/article/details/28440265