QT 按键

#ifndef _MYBUTTON_H

 #define _MYBUTTON_H



 #include <QPushButton>



 class MyButton:public QPushButton

 {

 Q_OBJECT//
只有加入了Q_OBJECT，你才能使用QT中的signal和slot机制。

 public:

explicit MyButton(const QString& text,

QWidget *parent);

 signals:

void clickedWithText(const QString text);

 private slots:

void onSelfClicked();

 };



#endif

#include "MyButton.h"




 MyButton::MyButton(const QString& text,
               QWidget *parent)
:QPushButton(text,parent)
 {
connect(this,SIGNAL(clicked()),
this,SLOT(onSelfClicked()));
 }




 //     void clickedWithText(const QString text);
 void MyButton::onSelfClicked()
 {
emit clickedWithText(this->text());
 }#ifndef _MYWINDOW_H
 #define _MYWINDOW_H


 #include <QWidget>
 //#include <QPushButton>
 #include "MyButton.h"
 #include <QLabel>
 #include <QVaBoxLayout>
 #include <QHBoxLayout>


 class MyWindow:public QWidget
 {
 Q_OBJECT
 private:
QLabel *lb_show;
MyButton *btn_A;
MyButton *btn_B;
MyButton *btn_C;
QVBoxLayout *mainLayout;
QHBoxLayout *keyLayout;
 public:
explicit MyWindow(QWidget* parent = 0);
 private slots:
void onClicked(QString text);
void onAClicked();
void onBClicked();
void onCClicked();
 };






 #endif #include "MyWindow.h"




 MyWindow::MyWindow(QWidget* parent)
:QWidget(parent)
 {
lb_show =new QLabel("",this);
btn_A = new MyButton("A",this);
btn_B = new MyButton("B",this);
btn_C = new MyButton("C",this);
QWidget *keyWidget = new QWidget(this);


mainLayout =new QVBoxLayout(this);
keyLayout =new QHBoxLayout(this);


keyLayout ->addWidget(btn_A);
keyLayout ->addWidget(btn_B);
keyLayout ->addWidget(btn_C);
keyWidget ->setLayout(keyLayout);


mainLayout->addWidget(lb_show);
mainLayout->addWidget(keyWidget);


this->setLayout(mainLayout);


// clickedWithText
connect(btn_A,SIGNAL(clickedWithText(QString)),
this,SLOT(onClicked(QString)));


connect(btn_B,SIGNAL(clickedWithText(QString)),
this,SLOT(onClicked(QString)));


connect(btn_C,SIGNAL(clickedWithText(QString)),
this,SLOT(onClicked(QString)));
 }




 void MyWindow::onClicked(QString text)
 {
QString str_show = lb_show->text();
str_show += text;
lb_show->setText(str_show);


 }


 void MyWindow::onAClicked()
 {
QString str_show = lb_show->text();
str_show += "A";
lb_show->setText(str_show);
 }




 void MyWindow::onBClicked()
 {
QString str_show = lb_show->text();
str_show += "B";
lb_show->setText(str_show);
 }
 void MyWindow::onCClicked()
 {
QString str_show = lb_show->text();
str_show += "C";
lb_show->setText(str_show);
 }#include <QApplication>
 #include "MyWindow.h"




 int main(int argc,char **argv)
 {
QApplication app(argc,argv);
MyWindow mw;
mw.show();
app.exec();
return 0;
 }