【QT】简易计算器实现

主要为了配合学习QT，还有一些bug，先不深究

#include "calc.h"
#include "ui_calc.h"

calc::calc(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::calc)
{
    ui->setupUi(this);

    QFont font=this->font();
    font.setPixelSize(40);
    this->setFont(font);
    window_init();
    key_init();
}

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

void calc::window_init()
{
    this->setMinimumSize(350,400);
    this->setMaximumSize(350,400);
    this->setWindowTitle("计算器");

    vbox=new QVBoxLayout(ui->centralWidget);
    title=new QLabel("计算器");
    title->setAlignment(Qt::AlignHCenter);

    vbox->addWidget(title);

    line=new QLineEdit();
    line->setMinimumHeight(60);
    line->setMaximumHeight(60);
    line->setAlignment(Qt::AlignRight);

    vbox->addWidget(line);
}

void calc::key_init()
{
    QString str="789+456-123*.0=/";
    grid =new QGridLayout();
    for(int i=0;i<4;i++)
    {
        for(int j=0;j<4;j++)
        {
            button[i*4+j]=new QPushButton();
            button[i*4+j]->setText(str.at(i*4+j));
            button[i*4+j]->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
//            connect(button[i*4+j],SIGNAL(clicked()),this,SLOT(button_click()));
            connect(button[i*4+j],&QPushButton::clicked,this,&calc::button_click);
            grid->addWidget(button[i*4+j],i,j);
        }
    }

    vbox->addLayout(grid);
}

void calc::button_click()
{

    QPushButton *button=static_cast<QPushButton *>(sender());
    QString ch=button->text();
    if(QString("0123456789.").contains(ch)>0)
    {
        inputnum(ch);
    }   
    else if(QString("+-*/").contains(ch)>0)
    {
        inputtype(ch);
        qDebug()<<ch+"inputtype";
    }
    else //=
    {
        output();
    }
}

void calc::inputnum(QString ch)
{
    if(clacs == 0)
    {
        Anum.append(ch);
        line->setText(Anum);
    }
    else{
        Bnum.append(ch);
        line->setText(Bnum);

        switch(clacs)
        {
              case 1:qDebug()<<clacs;line->setText(Anum+"+"+Bnum);break;
              case 2:qDebug()<<clacs;line->setText(Anum+"-"+Bnum);break;
              case 3:qDebug()<<clacs;line->setText(Anum+"*"+Bnum);break;
              case 4:qDebug()<<clacs;line->setText(Anum+"/"+Bnum);break;

        }
    }
}

void calc::inputtype(QString ch)
{
    switch(ch.at(0).toLatin1())
    {
//        case '+':clacs=1;break;
//        case '-':clacs=2;break;
//        case '*':clacs=3;break;
//        case '/':clacs=4;break;
          case '+':clacs=1;line->setText(Anum+"+");break;
          case '-':clacs=2;line->setText(Anum+"-");break;
          case '*':clacs=3;line->setText(Anum+"*");break;
          case '/':clacs=4;line->setText(Anum+"/");break;
    default:break;

    }
}

void calc::output()
{
    QString sum;
    switch (clacs) {
    case 1:sum=Anum+"+"+Bnum+"="+QString::number(Anum.toDouble()+Bnum.toDouble());break;
    case 2:sum=Anum+"-"+Bnum+"="+QString::number(Anum.toDouble()-Bnum.toDouble());break;
    case 3:sum=Anum+"*"+Bnum+"="+QString::number(Anum.toDouble()*Bnum.toDouble());break;
    case 4:sum=Anum+"/"+Bnum+"="+QString::number(Anum.toDouble()/Bnum.toDouble());break;
    default:
        break;
    }
    line->setText(sum);

    clacs=0;
    Anum.clear();
    Bnum.clear();
}

头文件.h代码

#ifndef CALC_H
#define CALC_H

#include <QMainWindow>
#include <QGridLayout>
#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QVBoxLayout>
#include <QDebug>
#include <QString>

namespace Ui {
class calc;
}

class calc : public QMainWindow
{
    Q_OBJECT

public:
    explicit calc(QWidget *parent = 0);
    ~calc();
    void window_init();
    void key_init();
    void inputnum(QString ch);
    void inputtype(QString ch);
    void output();
private slots:
    void button_click();
private:
    Ui::calc *ui;
    QLabel *title;
    QLineEdit *line;
    QPushButton *button[16];
    QGridLayout *grid;
    QVBoxLayout *vbox;

    QString Anum;
    QString Bnum;
    int clacs=0;
};

#endif // CALC_H

下面，对代码做简单解释

文本框与标题放在一个函数初始化，键盘放在另一个函数进行初始化

void calc::window_init()
{
    this->setMinimumSize(350,400);
    this->setMaximumSize(350,400);
    this->setWindowTitle("计算器");

    vbox=new QVBoxLayout(ui->centralWidget);
    title=new QLabel("计算器");
    title->setAlignment(Qt::AlignHCenter);

    vbox->addWidget(title);

    line=new QLineEdit();
    line->setMinimumHeight(60);
    line->setMaximumHeight(60);
    line->setAlignment(Qt::AlignRight);

    vbox->addWidget(line);
}

对键盘进行初始化，并对点击按钮建立槽函数

void calc::key_init()
{
    QString str="789+456-123*.0=/";
    grid =new QGridLayout();
    for(int i=0;i<4;i++)
    {
        for(int j=0;j<4;j++)
        {
            button[i*4+j]=new QPushButton();
            button[i*4+j]->setText(str.at(i*4+j));
            button[i*4+j]->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);
//            connect(button[i*4+j],SIGNAL(clicked()),this,SLOT(button_click()));
            connect(button[i*4+j],&QPushButton::clicked,this,&calc::button_click);
            grid->addWidget(button[i*4+j],i,j);
        }
    }

    vbox->addLayout(grid);
}

点击按钮的槽函数实现，如果是数字实现inputnum(ch);，如果是加减乘除实现inputtype(ch);，如果是等于实现output();

void calc::button_click()
{

    QPushButton *button=static_cast<QPushButton *>(sender());
    QString ch=button->text();
    if(QString("0123456789.").contains(ch)>0)
    {
        inputnum(ch);
    }   
    else if(QString("+-*/").contains(ch)>0)
    {
        inputtype(ch);
        qDebug()<<ch+"inputtype";
    }
    else //=
    {
        output();
    }
}

第一个数字存在Anum中，第二个数字存在Bnum中

void calc::inputnum(QString ch)
{
    if(clacs == 0)
    {
        Anum.append(ch);
        line->setText(Anum);
    }
    else{
        Bnum.append(ch);
        line->setText(Bnum);

        switch(clacs)
        {
              case 1:qDebug()<<clacs;line->setText(Anum+"+"+Bnum);break;
              case 2:qDebug()<<clacs;line->setText(Anum+"-"+Bnum);break;
              case 3:qDebug()<<clacs;line->setText(Anum+"*"+Bnum);break;
              case 4:qDebug()<<clacs;line->setText(Anum+"/"+Bnum);break;

        }
    }
}

 判断加减乘除操作，对clacs变量进行相应的赋值

void calc::inputtype(QString ch)
{
    switch(ch.at(0).toLatin1())
    {
//        case '+':clacs=1;break;
//        case '-':clacs=2;break;
//        case '*':clacs=3;break;
//        case '/':clacs=4;break;
          case '+':clacs=1;line->setText(Anum+"+");break;
          case '-':clacs=2;line->setText(Anum+"-");break;
          case '*':clacs=3;line->setText(Anum+"*");break;
          case '/':clacs=4;line->setText(Anum+"/");break;
    default:break;

    }
}

输出结果，讲clacs值重置为0

void calc::output()
{
    QString sum;
    switch (clacs) {
    case 1:sum=Anum+"+"+Bnum+"="+QString::number(Anum.toDouble()+Bnum.toDouble());break;
    case 2:sum=Anum+"-"+Bnum+"="+QString::number(Anum.toDouble()-Bnum.toDouble());break;
    case 3:sum=Anum+"*"+Bnum+"="+QString::number(Anum.toDouble()*Bnum.toDouble());break;
    case 4:sum=Anum+"/"+Bnum+"="+QString::number(Anum.toDouble()/Bnum.toDouble());break;
    default:
        break;
    }
    line->setText(sum);

    clacs=0;
    Anum.clear();
    Bnum.clear();
}