Qt学习例子5——calculatorwidget

一个简单的加法计算器，主要还是训练信号与槽的使用

 

程序代码如下：

 

//calculator.h

 

#ifndef CALCULATORWIDGET_H

#define CALCULATORWIDGET_H

#include <QWidget>

#include <QDialog>

#include <QLineEdit>

#include <QLabel>

class CalculatorWidget : public QDialog

{

    Q_OBJECT

public:

    explicit CalculatorWidget(QWidget *parent = 0);

    virtual ~CalculatorWidget();

private:

    QLineEdit *m_firstValue;

    QLineEdit *m_secondValue;

    QLabel *m_result;

signals:

public slots:

    void showMessage();

};

#endif // CALCULATORWIDGET_H

 

//calculator.cpp

 

#include "calculatorwidget.h"

#include <QtGui>

#include <QtDebug>

CalculatorWidget::CalculatorWidget(QWidget *parent) :

    QDialog(parent)

  ,m_firstValue(new QLineEdit())

  ,m_secondValue(new QLineEdit())

  ,m_result(new QLabel(""))

{

   QHBoxLayout *topLayout = new QHBoxLayout();

   topLayout->addWidget(m_firstValue);

   topLayout->addWidget(new QLabel("+"));

   topLayout->addWidget(m_secondValue);

   topLayout->addWidget(new QLabel("="));

   topLayout->addWidget(m_result);

   setLayout(topLayout);

   connect(m_secondValue,SIGNAL(returnPressed()),this,SLOT(showMessage()));

}

void CalculatorWidget::showMessage()

{

    QString firstValueText,secondValueText;

    int firstValue,secondValue,total;

    bool a,b;

    firstValueText=m_firstValue->text();

   secondValueText=m_secondValue->text();

    firstValue=firstValueText.toInt(&a);

    secondValue=secondValueText.toInt(&b);

    if(a && b)

    {

        total=firstValue+secondValue;

        qDebug("%d",total);

        m_result->setText(QString::number(total));

        qDebug("%s",qPrintable(m_result->text()));

    }

    else

    {

        m_result->setText("no result!");

    }

}

CalculatorWidget::~CalculatorWidget()

{

    delete m_firstValue;

    delete m_secondValue;

    delete m_result;

}

 

//main.cpp

 

#include <QApplication>

#include "calculatorwidget.h"

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

CalculatorWidget *cal=new CalculatorWidget;

cal->show();

return a.exec();

}

 

 

程序运行结果图：