QT入门笔记--建立连接--connect()

#include <QApplication>
#include<QPushButton>

int main(int argc, char *argv[])
{
    QApplication myapp(argc, argv);
    QPushButton *btn = new QPushButton("Quit");
    QObject::connect(btn,SIGNAL(clicked()),&myapp,SLOT(quit()));
    btn->show();

    return myapp.exec();
}

运行结果：

解析：
  QPushButton：
    The QPushButton widget provides a push button with a text or pixmap label.


 QPushButton::QPushButton ( const char * text, QWidget * parent=0, const char * name=0 )
  Constructs a push button with a text.The parent and name arguments are sent to the QWidget constructor.


 QObject: 
 The QObject class is the base class of all Qt objects that can deal with signals, slots and events.


  QMetaObject::Connection connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal,
                                     const typename QtPrivate::FunctionPointer<Func2>::Object *receiver, Func2 slot,
                                     Qt::ConnectionType type = Qt::AutoConnection)
Creates a connection of the given type from the signal in the sender object to the method in the receiver object.


    Tips:
        ＊connect(sender,signal,receiver,slot)：
             通俗地解释就是，对象A发射信号（这里当用户单击QPushButton时，该按钮就会发射一个click()信号），
             对象B接到信号作出对于处理（这里QApplication接到按钮的clicked()信号，调用用quit()。）
       ＊宏SIGNAL（）和SLOT（）是QT语法的一部分




附：
QT官网documentation中给出的connect()例子
QLabel *label = new QLabel;
QLineEdit *lineEdit = new QLineEdit;
QObject::connect(lineEdit, &QLineEdit::textChanged,
                 label,  &QLabel::setText);
This example ensures that the label always displays the current line edit text.