#include “dialog.h” #include 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())); connect(lineEdit,SIGNAL(textChanged(QString)),this,SLOT(showArea()));}
Dialog::~Dialog() {
}
void Dialog::showArea() { bool ok; QString tempStr; QString valueStr=lineEdit->text(); int valueInt=valueStr.toInt(&ok); double area=valueIntvalueIntPI; label2->setText(tempStr.setNum(area)); }
