4_2.cpp

一个qt设计的教程

#include <qapplication.h>
#include <qwidget.h>
#include <qpushbutton.h>
#include <qfont.h>
#include <qlineedit.h>
#include <qstring.h>

class MyMainWindow:public QWidget
{
 public:
    MyMainWindow();
 private:
    QPushButton *b1;
    QPushButton *b2;
    QPushButton *b3;
    QLineEdit *ledit;
};

MyMainWindow::MyMainWindow()
{
 setGeometry(100,100,300,200);
 
 b1 = new QPushButton("Click here to mark the text",this);
 b1->setGeometry(10,10,280,40);
 b1->setFont(QFont("Times",18,QFont::Bold));

 b2 = new QPushButton("Click here to unmark the text",this);
 b2->setGeometry(10,60,280,40);
 b2->setFont(QFont("Times",18,QFont::Bold));
 
 b3 = new QPushButton("Click here to remove the text",this);
 b3->setGeometry(10,110,280,40);
 b3->setFont(QFont("Times",18,QFont::Bold));

 ledit = new QLineEdit("This is a line of text",this);
 ledit->setGeometry(10,160,280,30);

 connect(b1,SIGNAL(clicked()),ledit,SLOT(selectAll()));
 connect(b2,SIGNAL(clicked()),ledit,SLOT(deselect()));
 connect(b3,SIGNAL(clicked()),ledit,SLOT(clear()));
}

main(int argc,char **argv)
{
 QApplication a(argc,argv);
 MyMainWindow w;

 a.setMainWidget(&w);
 w.show();
 a.exec();
}