Add new file

Dialog

+//第一部分
+#include "dialog.h"
+#include "ui_dialog.h"
+const static double PI=3.1416;
+
+Dialog::Dialog(QWidget *parent) :
+    QDialog(parent),
+    ui(new Ui::Dialog)
+{
+    ui->setupUi(this);
+}
+
+Dialog::~Dialog()
+{
+    delete ui;
+}
+
+void Dialog::on_pushButton_clicked()
+{
+    bool ok;
+    QString tempStr;
+    QString valueStr=ui->radiusLineEdit->text();
+    int valueInt=valueStr.toInt(&ok);
+    double area=valueInt*valueInt*PI;
+    ui->areaLabel_2->setText(tempStr.setNum(area));
+}
+
+void Dialog::on_radiusLineEdit_textChanged(const QString &arg1)
+{
+    bool ok;
+    QString tempStr;
+    QString valueStr=ui->radiusLineEdit->text();
+    int valueInt=valueStr.toInt(&ok);
+    double area=valueInt*valueInt*PI;
+    ui->areaLabel_2->setText(tempStr.setNum(area));
+}
+//第二部分
+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(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=valueInt*valueInt*PI;
+    label2->setText(tempStr.setNum(area));
+}