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 gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = 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 6.0.0


SOURCES += \
        main.cpp \
        dialog.cpp

HEADERS += \
        dialog.h

FORMS += \
        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_OBJECT

public:
    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 gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = 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 6.0.0

SOURCES += \
        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_OBJECT

public:
    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);
}