(轉）Qt使用connect函數時向slot傳遞參數

設想這樣一種場景：共有5個button，button1~button5，點擊button1時輸出“button 1 clicked”，點擊button2時輸出“button 2 clicked”，該如何實現呢？ 
最粗暴的實現是寫5個slot，然后將button與slot分別connect，但這明顯會增加許多重復代碼，不是一種好的實現。 
一種比較好的方式是使用QSignalMapper，它可以接收無參數的signal，然后重新發射出有參數的signal，這些參數的類型可以是int、QString、QWidget *或QObject *：

QSignalMapper *signalMapper = new QSignalMapper(this);

connect(button1, SIGNAL(triggered()), signalMapper, SLOT(map()));
connect(button2, SIGNAL(triggered()), signalMapper, SLOT(map()));
connect(button3, SIGNAL(triggered()), signalMapper, SLOT(map()));
connect(button4, SIGNAL(triggered()), signalMapper, SLOT(map()));
connect(button5, SIGNAL(triggered()), signalMapper, SLOT(map()));

signalMapper->setMapping(button1, 1);
signalMapper->setMapping(button2, 2);
signalMapper->setMapping(button3, 3);
signalMapper->setMapping(button4, 4);
signalMapper->setMapping(button5, 5);

connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(printMsg(int)));

轉自：https://blog.csdn.net/imred/article/details/72940365

參考：https://stackoverflow.com/questions/5153157/passing-an-argument-to-a-slot