Qt Demo—简单的四则运算计算器

项目功能

• 使用QT实现一个最简单的四则运算计算器
• 暂时只能实现单目运算

项目界面

项目文件

MainWindow类

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "model.h"
#include <QString>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:      //槽函数
    void getBtn_0();
    void getBtn_1();
    void getBtn_2();
    void getBtn_3();
    void getBtn_4();
    void getBtn_5();
    void getBtn_6();
    void getBtn_7();
    void getBtn_8();
    void getBtn_9();

    void on_btn_add_clicked();

    void on_btn_minus_clicked();

    void on_btn_multiply_clicked();

    void on_btn_divide_clicked();

    void on_btn_equal_clicked();

    void on_btn_clear_clicked();

private:
    Ui::MainWindow *ui;         //界面对象
    model *model1;               //模型对象
    QString temp;               //暂时存放数字字符串
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    this->model1 = new model;
    this->temp = "";

    //connect连接信号与槽
    connect(this->ui->btn_0, SIGNAL(clicked(bool)), this, SLOT(getBtn_0()));
    connect(this->ui->btn_1, SIGNAL(clicked(bool)), this, SLOT(getBtn_1()));
    connect(this->ui->btn_2, SIGNAL(clicked(bool)), this, SLOT(getBtn_2()));
    connect(this->ui->btn_3, SIGNAL(clicked(bool)), this, SLOT(getBtn_3()));
    connect(this->ui->btn_4, SIGNAL(clicked(bool)), this, SLOT(getBtn_4()));
    connect(this->ui->btn_5, SIGNAL(clicked(bool)), this, SLOT(getBtn_5()));
    connect(this->ui->btn_6, SIGNAL(clicked(bool)), this, SLOT(getBtn_6()));
    connect(this->ui->btn_7, SIGNAL(clicked(bool)), this, SLOT(getBtn_7()));
    connect(this->ui->btn_8, SIGNAL(clicked(bool)), this, SLOT(getBtn_8()));
    connect(this->ui->btn_9, SIGNAL(clicked(bool)), this, SLOT(getBtn_9()));

    //运算符使用“转到槽”机制
}

MainWindow::~MainWindow()
{
    delete ui;
}

//非bool类型：获取：属性名本身；设置：set+属性名
void MainWindow::getBtn_0()
{
    if(this->temp != ""){
        temp += this->ui->btn_0->text();
        this->ui->lbl_display->setText(temp);
    }else{
        
    }
}

void MainWindow::getBtn_1()
{
    temp += this->ui->btn_1->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_2()
{
    temp += this->ui->btn_2->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_3()
{
    temp += this->ui->btn_3->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_4()
{
    temp += this->ui->btn_4->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_5()
{
    temp += this->ui->btn_5->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_6()
{
    temp += this->ui->btn_6->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_7()
{
    temp += this->ui->btn_7->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_8()
{
    temp += this->ui->btn_8->text();
    this->ui->lbl_display->setText(temp);
}

void MainWindow::getBtn_9()
{
    temp += this->ui->btn_9->text();
    this->ui->lbl_display->setText(temp);
}

//运算符使用“转到槽”机制
void MainWindow::on_btn_add_clicked()
{
    //将temp储存到num1

    this->model1->setNum1(this->temp.toInt());
    temp = "";
    this->model1->setFlag("+");
    this->ui->lbl_display->setText("+");
}

void MainWindow::on_btn_minus_clicked()
{
    this->model1->setNum1(this->temp.toInt());
    this->model1->setFlag("-");
    this->ui->lbl_display->setText("-");
    temp = "";
}

void MainWindow::on_btn_multiply_clicked()
{
    this->model1->setNum1(this->temp.toInt());
    this->model1->setFlag("*");
    this->ui->lbl_display->setText("×");
    temp = "";
}

void MainWindow::on_btn_divide_clicked()
{
    this->model1->setNum1(this->temp.toInt());
    this->model1->setFlag("/");
    this->ui->lbl_display->setText("÷");
    temp = "";
}

void MainWindow::on_btn_equal_clicked()
{
    this->model1->setNum2(this->temp.toInt());
    this->ui->lbl_display->setText(model1->doExpr());
}

void MainWindow::on_btn_clear_clicked()
{
    this->model1->setNum1(0);
    this->model1->setNum2(0);
    this->model1->setFlag("");
    temp = "";
    this->ui->lbl_display->setText("0");
}

Model类

model.h

#ifndef MODEL_H
#define MODEL_H
#include <QString>

// num1 +-*/ num2

class model
{
public:
    model();
    void setNum1(int num);
    void setNum2(int num);
    void setFlag(QString flag);
    QString doExpr();   //计算结果

private:
    int num1, num2;
    QString flag;
    //int result;
};

#endif // MODEL_H

model.cpp

#include "model.h"

model::model()
{
    this->num1 = 0;
    this->num2 = 0;
}

void model::setNum1(int num)
{
    this->num1 = num;
}

void model::setNum2(int num)
{
    this->num2 = num;
}

void model::setFlag(QString flag)
{
    this->flag = flag;
}

QString model::doExpr()
{
    int result = 0;
    if(this->flag == "+"){
        result = num1 + num2;
    }else if(this->flag == '-'){
        result = num1 - num2;
    }else if(this->flag == "*"){
        result = num1 * num2;
    }else if(this->flag == "/"){
        if(num2 == 0){
            return "ERROR";
        }else{
            result = num1 / num2;
        }
    }else{
        return QString::number(num1);
    }
    return QString::number(result);
}

Main类

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
#if (QT_VERSION >= QT_VERSION_CHECK(5,9,0))
    QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
#endif

    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "model.h"
#include <QString>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:      //槽函数
    void getBtn_0();
    void getBtn_1();
    void getBtn_2();
    void getBtn_3();
    void getBtn_4();
    void getBtn_5();
    void getBtn_6();
    void getBtn_7();
    void getBtn_8();
    void getBtn_9();

    void on_btn_add_clicked();

    void on_btn_minus_clicked();

    void on_btn_multiply_clicked();

    void on_btn_divide_clicked();

    void on_btn_equal_clicked();

    void on_btn_clear_clicked();

private:
    Ui::MainWindow *ui;         //界面对象
    model *model1;               //模型对象
    QString temp;               //暂时存放数字字符串
};

#endif // MAINWINDOW_H