#include "dialog.h"
#include <QGridLayout>

const static double PI=3.1416;

Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    label1=new QLabel(this);
    label1->setText(tr("请输入圆的半径："));

    lineEdit=new QLineEdit(this);

    label2=new QLabel(this);

    button=new QPushButton(this);
    button->setText(tr("显示对应圆的面积"));

    QGridLayout *mainLayout=new QGridLayout(this);
    mainLayout->addWidget(label1,0,0);
    mainLayout->addWidget(lineEdit,0,1);
    mainLayout->addWidget(label2,1,0);
    mainLayout->addWidget(button,1,1);
    connect(button,SIGNAL(clicked()),this,SLOT(showArea()));
}

Dialog::~Dialog()
{

}
void Dialog::showArea()
{
    bool ok;
    QString tempStr;
    QString valueStr=lineEdit->text();
    int valueInt=valueStr.toInt(&ok);
    double area=valueInt*valueInt*PI;
    label2->setText(tempStr.setNum(area));
}