计算器
可以实现加减乘除，以及多个计算结果（连加、减、乘、除），支持按钮之间的联动，支持用户图形化界面。
思路
- 界面布局，包括数字按钮（0，1，2，3，4，5，6，7，8，9）、操作按钮（+、-、*、/、）、其他按钮（C == 清零、⬅ == 退货、）以及支持小数点按钮。
- 按钮设置完成之后，设置他们之间的联动。在这一步会用到之前讲到的自定义槽函数，因为点击按钮信号量发出后需要槽函数处理，而系统没有定义这种计算的槽函数，所以我们自定义这个计算过程。
- 界面的整体美化
实现
1. ui界面
2.计算（程序实现）
1.Testwidget.h头文件声明
#ifndef TESTWIDGET_H
#define TESTWIDGET_H
#include <QWidget>
#include <QCloseEvent>//关闭事件
#include <QMessageBox>
enum BtnType//按钮类型
{
Num,//数字
OP,//运算符
Dot,//点
Equal,//等于
Clear,//清除
Back,//退格
};
namespace Ui {
class TestWidget;
}
class TestWidget : public QWidget
{
Q_OBJECT
public:
explicit TestWidget(QWidget *parent = nullptr);
~TestWidget();
void closeEvent(QCloseEvent* event);//重写关闭事件
signals:
void testSigna(); //定义信号
private:
Ui::TestWidget *ui;
QString m_num1;//左操作数
QString m_num2;//右操作数
QString m_op;//运算符
public slots:
void OnClicked(BtnType _type,QString _str);
};
#endif // TESTWIDGET_H
2.Testwidget.cpp实现
#include "Testwidget.h"
#include "ui_Testwidget.h"
TestWidget::TestWidget(QWidget *parent) :
QWidget(parent),
ui(new Ui::TestWidget)
{
ui->setupUi(this);
//数字按钮绑定
connect(ui->pushButton0,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"0"); });
connect(ui->pushButton1,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"1"); });
connect(ui->pushButton2,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"2"); });
connect(ui->pushButton3,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"3"); });
connect(ui->pushButton4,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"4"); });
connect(ui->pushButton5,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"5"); });
connect(ui->pushButton6,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"6"); });
connect(ui->pushButton7,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"7"); });
connect(ui->pushButton8,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"8"); });
connect(ui->pushButton9,&QPushButton::clicked,this,[=]()->void{ OnClicked(Num,"9"); });
//运算符按钮绑定
connect(ui->addButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(OP,"+"); });
connect(ui->subButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(OP,"-"); });
connect(ui->multButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(OP,"*"); });
connect(ui->divButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(OP,"/"); });
//点按钮绑定
connect(ui->pointbutton,&QPushButton::clicked,this,[=]()->void{ OnClicked(Dot,"."); });
//等于按钮绑定
connect(ui->equalbutton,&QPushButton::clicked,this,[=]()->void{ OnClicked(Equal,"="); });
//清除按钮绑定
connect(ui->clearButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(Clear," "); });
//退格按钮绑定
connect(ui->backButton,&QPushButton::clicked,this,[=]()->void{ OnClicked(Back," Back " ); });
}
TestWidget::~TestWidget()
{
delete ui;
}
//关闭窗口后进行操作
void TestWidget::closeEvent(QCloseEvent *event)
{
//窗口关闭时提示
QMessageBox::StandardButton result = QMessageBox::question(this, " 退出程序 " , " 确定退出系统 " ,
QMessageBox::Yes | QMessageBox::No );
if(result == QMessageBox::Yes)
{
event->accept();
emit testSigna();//发送信号
}
else
{
event->ignore();
}
}
void TestWidget::OnClicked(BtnType _type, QString _str)
{
switch (_type)//按钮类型
{
case Num:
{
if(m_op.isEmpty())//如果运算符为空，说明输入的是操作数1
{
m_num1 += _str;//拼接
}
else//操作符2
{
m_num2 += _str;
}
break;
}
case OP://运算符
{
//实现连乘计算
if(!m_num1.isEmpty() && !m_num2.isEmpty())
{
double num1 = m_num1.toDouble();
double num2 = m_num2.toDouble();
double result = 0.0;
if(m_op == "+")
{
result = num1 + num2;
}
else if("-" == m_op)
{
result = num1 - num2;
}
else if("*" == m_op)
{
result = num1 * num2;
}
else
{
if(0.0 != num2)
{
result = num1 / num2;
}
else
{
ui->display->setText("除数不能为0");
return;
}
}
ui->display->setText(QString::number(result));
m_num1 = QString::number(result);
m_num2.clear();
}
m_op = _str;
break;
}
case Dot:
{
if(m_op.isEmpty())//操作数1的小数点
{
if(!m_num1.isEmpty() && !m_num1.contains("."))//操作数1没有点且不空
{
m_num1 += _str;
}
}
else//操作数2的点
{
if(!m_num2.isEmpty() && !m_num2.contains("."))//操作数1没有点且不空
{
m_num2 += _str;
}
}
break;
}
case Clear:
{
m_num1.clear();
m_num2.clear();
m_op.clear();
break;
}
case Equal:
{
if(m_num1.isEmpty() || m_num2.isEmpty() ||m_op.isEmpty())
{
m_num1.clear();
m_num2.clear();
m_op.clear();
return;
}
double num1 = m_num1.toDouble();
double num2 = m_num2.toDouble();
double result = 0.0;
if(m_op == "+")
{
result = num1 + num2;
}
else if("-" == m_op)
{
result = num1 - num2;
}
else if("*" == m_op)
{
result = num1 * num2;
}
else
{
if(0.0 != num2)
{
result = num1 / num2;
}
else
{
ui->display->setText("除数不能为0");
return;
}
}
ui->display->setText(QString::number(result));
//m_num1.clear();
//m_num2.clear();
//m_op.clear();
return;
}
case Back:
{
if(!m_num1.isEmpty() && !m_num2.isEmpty() && !m_op.isEmpty())//删除操作数2
{
m_num2.chop(1);
}
else if(!m_num1.isEmpty() && !m_op.isEmpty())//删除运算符
{
m_op.chop(1);
}
else//删除操作数1
{
m_num1.chop(1);
}
break;
}
}
ui->display->setText(m_num1 + m_op + m_num2);
}
结果
