QT简单实例

QT简单实例

一：通过拖动创建

1.创建工程

1.1 新建项目->Application->Qt Widegets Application
1.2 基类->QDialog

2.拖动控件实现响应

2.1 双击 dialog.ui
2.2 拖动 Display Widgets–Label、Input Widgets–Line Edit、Buttons–Push button

2.3修改控件属性

2.4最后，修改areaLabel2的“frameShape”为Panel;“frameShadow”为Sunken，如图1.19所示。最终效果如图所示

2.5添加控件响应函数
1）方式1:在LineEdit文本框内输入半径值，然后单击“计算”按钮，则在areaLabel 2中显示对应的圆面积。编写代码步骤如下。(1)在“计算”按钮上单击鼠标右键，在弹出的下拉菜单中选择“转到槽…”命令，如图1.22所示。在弹出的对话框中选择“clicked()”信号，如图所示，

2）方式2:在LineEdit内输入半径值，不需要单击按钮触发单击事件，直接就在areaLabel 2中显示圆面积。编写代码步骤如下。(1)在“LineEdit”编辑框上单击鼠标右键，在弹出的下拉菜单中选择“转到槽…”菜单项，在弹出的对话框中选择“textChanged(QString)”信号，如图所示。

3.文件目录

3.1 TestQDialog.pro

#-------------------------------------------------
#
# Project created by QtCreator 2025-04-15T09:43:14
#
#-------------------------------------------------QT       += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = TestQDialogSelf
TEMPLATE = app# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += \main.cpp \dialog.cppHEADERS += \dialog.hFORMS += \dialog.ui

3.2 main.cpp

#include "dialog.h"
#include <QApplication>
int main(int argc, char *argv[])
{QApplication a(argc, argv);Dialog w;w.show();return a.exec();
}

3.3 dialog.h

#ifndef DIALOG_H
#define DIALOG_H#include <QDialog>namespace Ui {
class Dialog;
}class Dialog : public QDialog
{Q_OBJECTpublic:explicit Dialog(QWidget *parent = 0);~Dialog();protected:Ui::Dialog *ui;protected slots:void on_countBtn_clicked();
private slots:void on_radiusLineEdit_textChanged(const QString &arg1);
};#endif // DIALOG_H

3.4 dialog.cpp

#include "dialog.h"
#include "ui_dialog.h"Dialog::Dialog(QWidget *parent) :QDialog(parent),ui(new Ui::Dialog)
{ui->setupUi(this);//删除标题栏setWindowFlags(Qt::FramelessWindowHint);// 背景黑色//setStyleSheet("background-color: black;");
}Dialog::~Dialog()
{delete ui;
}void Dialog::on_countBtn_clicked()
{const double PI = 3.1416;QString str = ui->radiusLineEdit->text();int nVal = str.toInt();double dArea = PI*nVal*nVal;QString strRes;strRes.setNum(dArea);ui->areaLabel_2->setText(strRes);
}void Dialog::on_radiusLineEdit_textChanged(const QString &arg1)
{const double PI = 3.1416;int nVal = arg1.toInt();double dArea = nVal*nVal*PI;QString strRes;ui->areaLabel_2->setText(strRes.setNum(dArea));
}

二：通过动态创建

1.创建工程

1.1 新建项目->Application->Qt Widegets Application
1.2 基类->QDialog

2.文件目录

2.1 TestQDialogSelf.pro

#-------------------------------------------------
#
# Project created by QtCreator 2025-04-15T09:43:14
#
#-------------------------------------------------QT       += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = TestQDialogSelf
TEMPLATE = app# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += \main.cpp \dialog.cpp
HEADERS += \dialog.h
FORMS += \dialog.ui

2.2 main.cpp

#include "dialog.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);Dialog w;w.show();return a.exec();
}

2.3 dialog.h

#ifndef DIALOG_H
#define DIALOG_H#include <QDialog>
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>namespace Ui {
class Dialog;
}class Dialog : public QDialog
{Q_OBJECTpublic:explicit Dialog(QWidget *parent = 0);~Dialog();protected slots:void showArea();void showChangeArea(QString str);protected:Ui::Dialog *ui;protected:QLabel* pLabel_1;QLabel* pLabel_2;QLineEdit* pLineEdit;QPushButton* pPushButton;
};
#endif // DIALOG_H

2.4 dialog.cpp

#include "dialog.h"
#include "ui_dialog.h"
#include <QGridLayout>Dialog::Dialog(QWidget *parent) :QDialog(parent),ui(new Ui::Dialog)
{ui->setupUi(this);//去掉标题栏setWindowFlags(Qt::FramelessWindowHint);//创建控件pLabel_1 = new QLabel(this);pLabel_1->setText("请输入圆的半径：");pLabel_2 = new QLabel(this);pLineEdit = new QLineEdit(this);pPushButton = new QPushButton(this);pPushButton->setText("显示对应圆的面积");//创建容器QGridLayout* mainLayout = new QGridLayout(this);mainLayout->addWidget(pLabel_1,0,0);mainLayout->addWidget(pLineEdit,0,1);mainLayout->addWidget(pLabel_2,1,0);mainLayout->addWidget(pPushButton,1,1);//绑定控件响应函数connect(pPushButton,SIGNAL(clicked()),this,SLOT(showArea()));connect(pLineEdit,SIGNAL(textChanged(QString)),this,SLOT(showChangeArea(QString)));
}Dialog::~Dialog()
{delete ui;
}void Dialog::showArea()
{const double PI = 3.1416;QString str = pLineEdit->text();int nVal = str.toInt();double dArea = PI*nVal*nVal;QString strRes;strRes.setNum(dArea);pLabel_2->setText(strRes);
}void Dialog::showChangeArea(QString str)
{const double PI = 3.1416;int nVal = str.toInt();double dArea = PI*nVal*nVal;QString strRes;strRes.setNum(dArea);pLabel_2->setText(strRes);
}