【QT】QT+VS2019的基本功能的计算器(附项目资源)

引文

链接: https://pan.baidu.com/s/1lKyXTOS8UXJtFRjCASlcA 提取码: vh24

一份在Visual Studio的QT中写的简单的闹钟，Qt GUI Application项目，经过调试可能还是会有少些bug，现在将小玩意同大家分享，很期待有朋友一起讨论，文章项目资源可以自行下载，我在调试时的qDebug还留着，方便理解。

代码中主要依靠 IsOperatorClicked 和 IsStoredNumber 来判断是否进行运算，下面是一个简单的运行演示。

步骤	点击的按钮
初始	IsOperatorClicked = false; IsStoredNumber = false;
1	num4
	displayLabel.append(button->text());
2	actionMul(+)
	storeNumber=4; IsStoredNumber= true
	storeOperator=+; IsOperatorClicked= true
3	num2
	IsOperatorClicked = false
4	actionEqual(=)
	calculate_result(); IsStoredNumber = false

写文章才发现英语单词写错了尬尬，把Equal写成Euqal，就不改了哈，看到的知到它是错的

Calculator.ui

界面设计及控件命名

Calculator.h

#pragma once
#include <QMainWindow>
#include "ui_Calculator.h"

#include <QAbstractButton>
#include <QtWidgets/QButtonGroup>
#include <QtCore>

namespace Ui {
    class Calculator;
}

class Calculator : public QMainWindow
{
	Q_OBJECT

public:
	Calculator(QWidget *parent = 0);
    ~Calculator();

private slots:
    void numberGroup_clicked(QAbstractButton*);     //123456789
    void actionGroup_clicked(QAbstractButton*);     //+-*/

    void on_actionDel_clicked();        //Del
    void on_actionEqual_clicked();       //=
    void on_comma_clicked();            //.
    void on_actionClear_clicked();      //C
    void on_actionPercent_clicked();    //%
    void on_actionSign_clicked();       //+/-

private:
	Ui::CalculatorClass* ui;

    //限制数值长度
    const int DIGIT_LIMIT = 16;
    //用于检查上一个点击的按钮是否为运算符
    bool IsOperatorClicked;
    //用于检查数字是否存储在内存中
    bool IsStoredNumber;
    //存储最后点击的运算符
    QChar storedOperator;
    //存储数字
    double storedNumber;
    //根据存储的号码和显示的号码计算结果
    void calculate_result();

    QButtonGroup* actionGroup;      //运算符按钮组
    QButtonGroup* numberGroup;      //数字按钮组
};

Calculator.cpp

#include "Calculator.h"

Calculator::Calculator(QWidget* parent)
	: QMainWindow(parent),
	ui(new Ui::CalculatorClass),
	storedNumber(0)
{
	ui->setupUi(this);

	//设置空显示面板
	ui->displayLabel->clear();

	//将operator和store number和comma标志设置为false
	IsOperatorClicked = false;
	IsStoredNumber = false;

	//分配空间
	numberGroup = new QButtonGroup;
	actionGroup = new QButtonGroup;

	//将按钮放入
	numberGroup->addButton(ui->num1, 1);
	numberGroup->addButton(ui->num2, 2);
	numberGroup->addButton(ui->num3, 2);
	numberGroup->addButton(ui->num4, 4);
	numberGroup->addButton(ui->num5, 5);
	numberGroup->addButton(ui->num6, 6);
	numberGroup->addButton(ui->num7, 7);
	numberGroup->addButton(ui->num8, 8);
	numberGroup->addButton(ui->num9, 9);
	numberGroup->addButton(ui->num0, 0);

	actionGroup->addButton(ui->actionAdd, 1);
	actionGroup->addButton(ui->actionSub, 2);
	actionGroup->addButton(ui->actionMul, 3);
	actionGroup->addButton(ui->actionDiv, 4);
	actionGroup->addButton(ui->actionEuqal, 5);

	//连接信号和槽
	numberGroup->connect(numberGroup, SIGNAL(buttonClicked(QAbstractButton*)),
		this, SLOT(numberGroup_clicked(QAbstractButton*)));

	//连接信号和槽
	actionGroup->connect(actionGroup, SIGNAL(buttonClicked(QAbstractButton*)),
		this, SLOT(actionGroup_clicked(QAbstractButton*)));

	//设置窗口固定宽度和高度
	this->setFixedSize(QSize(412, 433));
}

Calculator::~Calculator()
{
	delete ui;
	delete numberGroup;
	delete actionGroup;
}

//单击数字按钮时调用
void Calculator::numberGroup_clicked(QAbstractButton* button)
{
	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();
	qDebug() << "numberGroup_clicked: " << displayLabel;

	/*检查上一个点击的按钮是否是运算符按钮。
	*如果是，请清除显示并将标志设置为false。然后继续
	*再添加新的数字。*/
	if (IsOperatorClicked)
	{
		displayLabel.clear();	//清空之前的数字

		qDebug() << "numberGroup_clicked: " << displayLabel;

		IsOperatorClicked = false;
	}

	//超过数字限制，就不加数字
	if (displayLabel.length() >= DIGIT_LIMIT) {
		return;
	}

	//末尾添加点击的数字
	displayLabel.append(button->text());

	qDebug() << "numberGroup_clicked: " << displayLabel;

	//将数字设回显示
	ui->displayLabel->setText(displayLabel);

}

//+-*/
void Calculator::actionGroup_clicked(QAbstractButton* button)
{

	/*如果上一个点击的按钮是运算符，则只需保存该运算符，然后退出
	*如果上一个点击的按钮不是运算符的话，我们需要看看是否只需要保存
	*如果内存中已经存储了一个数字，则执行计算并存储结果*/

	if (IsOperatorClicked)		//如果上一个是运算符
	{
		storedOperator = button->text().at(0);	//保存操作符

		qDebug() << "actionGroup_clicked: " << storedOperator;
	}
	else  ////如果上一个不是运算符
	{
		if (IsStoredNumber)		//如果有数字
		{
			calculate_result();
		}
		else
		{
			//从显示中获取字符串
			QString displayLabel = ui->displayLabel->text();

			qDebug() << "actionGroup_clicked: " << displayLabel;

			//将字符串转换为双精度并保存
			storedNumber = displayLabel.toDouble();

			qDebug() << "actionGroup_clicked: " << storedNumber;

			//设置标志，指示我们现在在内存中存储了一个数字
			IsStoredNumber = true;


		}

		//设置上次单击的按钮是运算符的标志
		IsOperatorClicked = true;

		//将运算符存储在内存中
		storedOperator = button->text().at(0);

		qDebug() << "actionGroup_clicked: " << storedOperator;
	}
}

//delete
void Calculator::on_actionDel_clicked()
{

	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();

	qDebug() << "on_actionDel_clicked: " << displayLabel;

	//检查标签是否为空
	if (displayLabel.length() == 0)  return;

	//从字符串中删除最后一个数字
	displayLabel.QString::chop(1);

	qDebug() << "on_actionDel_clicked: " << displayLabel;

	//将数字设回显示
	ui->displayLabel->setText(displayLabel);
}

//点击=
void Calculator::on_actionEqual_clicked()
{

	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();

	qDebug() << "on_actionEqual_clicked: " << displayLabel;

	/*必须在内存中保存一个数字才能计算结果。
	*此外，显示屏上应显示一个至少有一位数字的数字，并且
	*单击的最后一个按钮不应是运算符*/
	if (!IsStoredNumber || displayLabel.length() < 1 || IsOperatorClicked)  return;

	//计算结果并显示
	calculate_result();

	IsStoredNumber = false;
}

//点击.
void Calculator::on_comma_clicked()
{
	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();
	qDebug() << "on_comma_clicked: " << displayLabel;

	/*检查是否超过数字长度
	*检查是否已经存在另一个逗号。*/
	if (displayLabel.length() >= (DIGIT_LIMIT - 1) || displayLabel.contains('.', Qt::CaseSensitive)) return;

	//如果label为空，则添加零，然后附加逗号
	if (displayLabel.length() == 0) 
	{
		displayLabel = "0";
	}

	//附加逗号
	displayLabel.append('.');

	qDebug() << "on_comma_clicked: " << displayLabel;

	//将数字设回显示
	ui->displayLabel->setText(displayLabel);
}

//点击C
void Calculator::on_actionClear_clicked()
{
	//清空
	ui->displayLabel->clear();

	qDebug() << "on_actionClear_clicked: " << ui->displayLabel->text();

	IsOperatorClicked = false;
	IsStoredNumber = false;
}

//点击%
void Calculator::on_actionPercent_clicked()
{
	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();

	qDebug() << "on_actionPercent_clicked: " << displayLabel;

	double percentage = displayLabel.toDouble();

	//乘以0.01就可以得到一个百分比
	percentage *= 0.01;

	//因为可能有溢出，所以精确的转换数字
	displayLabel = QString::number(percentage, 'g', DIGIT_LIMIT);

	ui->displayLabel->setText(displayLabel);
}

//点击+/-
void Calculator::on_actionSign_clicked()
{
	QString displayLabel = ui->displayLabel->text();

	qDebug() << "on_actionSign_clicked: " << displayLabel;

	double percentage = displayLabel.toDouble();

	//乘以-1就改变符号
	percentage *= -1;

	displayLabel = QString::number(percentage, 'g', DIGIT_LIMIT);

	ui->displayLabel->setText(displayLabel);
}


//计算
void Calculator::calculate_result()
{
	//获取QLabel字符串
	QString displayLabel = ui->displayLabel->text();

	qDebug() << "calculate_result: " << displayLabel;

	//如果显示的数字以逗号结尾，就删除逗号。
	if (displayLabel.endsWith('.', Qt::CaseSensitive)) {
		displayLabel.QString::chop(1);
	}

	//根据运算符决定
	if (storedOperator == '+') {
		storedNumber += displayLabel.toDouble();

		qDebug() << "calculate_result: " << "+";
	}
	else if (storedOperator == '-') {
		storedNumber -= displayLabel.toDouble();

		qDebug() << "calculate_result: " << "-";
	}
	else if (storedOperator == '*') {
		storedNumber *= displayLabel.toDouble();

		qDebug() << "calculate_result: " << "*";
	}
	else if (storedOperator == '/') {
		storedNumber /= displayLabel.toDouble();

		qDebug() << "calculate_result: " << "/";
	}

	//因为可能有溢出，所以精确的转换数字

	//返回与数字n相等的字符串，该字符串根据指定的格式和精度进行格式化。有关详细信息，请参见参数格式。
	displayLabel = QString::number(storedNumber, 'g', DIGIT_LIMIT);

	qDebug() << "calculate_result: " << displayLabel;

	//将计算好的数值呈现
	ui->displayLabel->setText(displayLabel);
}

main.cpp

#include "Calculator.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	Calculator w;
	w.show();
	return a.exec();
}

如有不足之处，还望指正 ¹。

---

1. 如果对您有帮助可以点赞、收藏、关注，将会是我最大的动力 ↩︎