qt5实现计算器

程序员文章站 2022-03-15 21:13:07

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（1）取出按钮中的字符

QString line = ui->pushButton1->text() //取出按钮pushButton1中的字符存放到line中

（2）设置输入框中显示的内容

ui->lineEdit->setText(line); //设置输入框lineEdit中显示的内容，line为要显示的内容

（3）将整形、浮点型、数值转换成字符

 ui->lineEdit->setText(QString::number(sum)); //将浮点型转换成字符

（4）addwidgt说明：

//放置一个控件到一个单元格  
void    addWidget ( QWidget * widget, int row, int column, Qt::Alignment alignment = 0 )  
 //如果放置的控件超出一个单元格，则使用该方法  
void    addWidget ( QWidget * widget, int fromRow, int fromColumn, int rowSpan, int columnSpan, Qt::Alignment alignment = 0 )  
参数说明：
    1）row：指放置控件的网格行号（行号从0开始）；
    2）colum：指放置控件的网格列号（从0开始）；
    3）alignment：对齐方式。
    4）fromRow：指放置控件的起始网格行号；
    5）fromColumn：指放置控件的起始网格列号；
    6）rowSpan：指放置控件占多少行；
    7）columnSpan：指放置控件占多少列。

计算器功能：对整数实现+、-、*、/编辑框的小功能

1,实现代码如下
main.cpp

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

int main(int argc, char *argv[])
{

    QApplication a(argc, argv);

    MainWindow w;

    w.show();

    w.setFixedSize(400,300);

    w.setWindowTitle("计算器");

    w.myLayout();

    return a.exec();

}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QPushButton>
#include <QLineEdit>

class MainWindow : public QMainWindow
{
    Q_OBJECT

protected:

    int num1,num2,result; //标记第一个数，第二个数和结果

    int operat; //运算符号

    int operat_flag;//标记是否输入符号

    QLineEdit *data;

    QPushButton *button_0;

    QPushButton *button_1;

    QPushButton *button_2;

    QPushButton *button_3;

    QPushButton *button_4;

    QPushButton *button_5;

    QPushButton *button_6;

    QPushButton *button_7;

    QPushButton *button_8;

    QPushButton *button_9;

    QPushButton *button_ce;

    QPushButton *button_jia;

    QPushButton *button_jian;

    QPushButton *button_cheng;

    QPushButton *button_chu;

    QPushButton *button_result;

    QString s;
 
public:

    MainWindow(QWidget *parent = 0);

    ~MainWindow();

public:

    void myLayout();

    void operation();

    void readNum(int num);

    void init_data();

private slots:

    void button_0_clicked();

    void button_1_clicked();

    void button_2_clicked();

    void button_3_clicked();

    void button_4_clicked();

    void button_5_clicked();

    void button_6_clicked();

    void button_7_clicked();

    void button_8_clicked();

    void button_9_clicked();

    void button_ce_clicked();

    void button_result_clicked();

    void button_cheng_clicked();

    void button_chu_clicked();

    void button_jia_clicked();

    void button_jian_clicked();

};
#endif

mainwindow.cpp

#include "mainwindow.h"

#include <QPushButton>

#include <QLineEdit>

#include <QGridLayout>

MainWindow::MainWindow(QWidget *parent)

    : QMainWindow(parent)
{

}


void MainWindow::myLayout(){

    QWidget *centerWindow = new QWidget;

    this->setCentralWidget(centerWindow);

    s = "";

    init_data();

    data = new QLineEdit("");

    button_0 = new QPushButton("0");

    button_1 = new QPushButton("1");

    button_2 = new QPushButton("2");

    button_3 = new QPushButton("3");

    button_4 = new QPushButton("4");

    button_5 = new QPushButton("5");

    button_6 = new QPushButton("6");

    button_7 = new QPushButton("7");

    button_8 = new QPushButton("8");

    button_9 = new QPushButton("9");

    button_ce = new QPushButton("CE");

    button_jia = new QPushButton("+");

    button_jian = new QPushButton("-");

    button_cheng = new QPushButton("*");

    button_chu = new QPushButton("/");

    button_result = new QPushButton("=");

    data->setFixedHeight(30);

    button_0->setMinimumHeight(50);

    button_1->setMinimumHeight(50);

    button_2->setMinimumHeight(50);

    button_3->setMinimumHeight(50);

    button_4->setMinimumHeight(50);

    button_5->setMinimumHeight(50);

    button_6->setMinimumHeight(50);

    button_7->setMinimumHeight(50);

    button_8->setMinimumHeight(50);

    button_9->setMinimumHeight(50);

    button_ce->setMinimumHeight(50);

    button_jia->setMinimumHeight(50);

    button_jian->setMinimumHeight(50);

    button_cheng->setMinimumHeight(50);

    button_chu->setMinimumHeight(50);

    button_result->setMinimumHeight(50);

    //连接信号

    connect(button_0,SIGNAL(clicked(bool)),this,SLOT(button_0_clicked()));

    connect(button_1,SIGNAL(clicked(bool)),this,SLOT(button_1_clicked()));

    connect(button_2,SIGNAL(clicked(bool)),this,SLOT(button_2_clicked()));

    connect(button_3,SIGNAL(clicked(bool)),this,SLOT(button_3_clicked()));

    connect(button_4,SIGNAL(clicked(bool)),this,SLOT(button_4_clicked()));

    connect(button_5,SIGNAL(clicked(bool)),this,SLOT(button_5_clicked()));

    connect(button_6,SIGNAL(clicked(bool)),this,SLOT(button_6_clicked()));

    connect(button_7,SIGNAL(clicked(bool)),this,SLOT(button_7_clicked()));

    connect(button_8,SIGNAL(clicked(bool)),this,SLOT(button_8_clicked()));

    connect(button_9,SIGNAL(clicked(bool)),this,SLOT(button_9_clicked()));

    connect(button_jia,SIGNAL(clicked(bool)),this,SLOT(button_jia_clicked()));

    connect(button_jian,SIGNAL(clicked(bool)),this,SLOT(button_jian_clicked()));

    connect(button_cheng,SIGNAL(clicked(bool)),this,SLOT(button_cheng_clicked()));

    connect(button_chu,SIGNAL(clicked(bool)),this,SLOT(button_chu_clicked()));

    connect(button_ce,SIGNAL(clicked(bool)),this,SLOT(button_ce_clicked()));

    connect(button_result,SIGNAL(clicked(bool)),this,SLOT(button_result_clicked()));

    QGridLayout * layout = new QGridLayout;
 
    layout->addWidget(data,1,1,1,4,Qt::Alignment()); //控件超出一个单元格,数据输出口

    layout->addWidget(button_1,2,1,Qt::Alignment());

    layout->addWidget(button_2,2,2,Qt::Alignment());

    layout->addWidget(button_3,2,3,Qt::Alignment());

    layout->addWidget(button_jia,2,4,Qt::Alignment());

    layout->addWidget(button_4,3,1,Qt::Alignment());

    layout->addWidget(button_5,3,2,Qt::Alignment());

    layout->addWidget(button_6,3,3,Qt::Alignment());

    layout->addWidget(button_jian,3,4,Qt::Alignment());

    layout->addWidget(button_7,4,1,Qt::Alignment());

    layout->addWidget(button_8,4,2,Qt::Alignment());

    layout->addWidget(button_9,4,3,Qt::Alignment());

    layout->addWidget(button_cheng,4,4,Qt::Alignment());

    layout->addWidget(button_ce,5,1,Qt::Alignment());

    layout->addWidget(button_0,5,2,Qt::Alignment());

    layout->addWidget(button_result,5,3,Qt::Alignment());

    layout->addWidget(button_chu,5,4,Qt::Alignment());

    layout->setMargin(12);

    centerWindow->setLayout(layout);

}
 
MainWindow::~MainWindow()
{
 

}

void MainWindow::init_data()
{

    num1 = 0;

    num2 = 0;

    operat_flag = 0;

}

 

void MainWindow::readNum(int num)

{

      //如果是第一个操作数

      if(operat_flag == 0){

          num1 = num1 * 10 + num;

      }

      //如果是第二个操作数

      else{

          num2 = num2 * 10 + num;

      }

}

 

void MainWindow::operation()

{

    switch(operat){

    case 1:

        result = num1 + num2;

        break;

    case 2:

        result = num1 - num2;

        break;

    case 3:

        result = num1 * num2;

        break;

    case 4:

        result = num1 / num2;

        break;

    }

    //把结果存到num1中，清零num2

    num1 = result;

    num2 = 0;

    s = QString::number(result,10);

}

 
void MainWindow::button_0_clicked(){

    s += "0";

    data->setText(s);

    readNum(0);

}


void MainWindow::button_1_clicked(){

    s += "1";

    data->setText(s);

    readNum(1);

}


void MainWindow::button_2_clicked(){

    s += "2";

    data->setText(s);

    readNum(2);

}
 
void MainWindow::button_3_clicked(){

    s += "3";

    data->setText(s);

    readNum(3);

}

void MainWindow::button_4_clicked(){

    s += "4";

    data->setText(s);

    readNum(4);

}
 
void MainWindow::button_5_clicked(){

    s += "5";

    data->setText(s);

    readNum(5);

}

void MainWindow::button_6_clicked(){

    s += "6";

    data->setText(s);

    readNum(6);

}
 
void MainWindow::button_7_clicked(){

    s += "7";

    data->setText(s);

    readNum(7);

}

 
void MainWindow::button_8_clicked(){

    s += "8";

    data->setText(s);

    readNum(8);

}
 

void MainWindow::button_9_clicked(){

    s += "9";

    data->setText(s);

    readNum(9);

}


void MainWindow::button_ce_clicked(){

    s = "";

    data->setText("");

    //初始化数据

    init_data();

}

void MainWindow::button_jia_clicked(){

    s += "+";

    data->setText(s);

    operat_flag = 1;

    operat = 1;

}

void MainWindow::button_jian_clicked(){

    s += "-";

    data->setText(s);

    operat_flag = 1;

    operat = 2;

}
 
void MainWindow::button_cheng_clicked(){

    s += "*";

    data->setText(s);

    operat_flag = 1;

    operat = 3;

}
 
void MainWindow::button_chu_clicked(){

    s += "/";

    data->setText(s);

    operat_flag = 1;

    operat = 4;

}

void MainWindow::button_result_clicked(){

    operation();

    QString a = QString::number(result,10);

    data->setText(a);

}

完整代码连接：https://download.csdn.net/download/qq_40008325/11015502

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