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Archived:Como criar uma calculadora simples, em Qt

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Archived.pngAquivado: Este artigo foi arquivado, pois o conteúdo não é mais considerado relevante para se criar soluções comerciais atuais. Se você achar que este artigo ainda é importante, inclua o template {{ForArchiveReview|escreva a sua justificativa}}.

Qt Quick should be used for all UI development on mobile devices. The approach described in this article (based on QWidget) is deprecated.

Este trecho de código demonstra como criar uma simples calculadora usando Qt.

Article Metadata

Testado com
Aparelho(s): Emulator

Compatibilidade
Plataforma(s): S60 3rd Edition FP1, S60 3rd Edition FP2, S60 5th Edition
Symbian

Artigo
Palavras-chave: QString, Push Button, Text Label
Tradução:
Por valderind4
Última alteração feita por hamishwillee em 11 Oct 2012

Contents

Arquivo de cabeçalho

Cal.h

#ifndef CAL_H
#define CAL_H
 
#include <QtGui/QWidget>
#include "ui_cal.h"
#include<QString>
#include<QPushButton>
#include<QLineEdit>
#include<QHBoxLayout>
#include<QVBoxLayout>
#include<QFormLayout>
class cal : public QWidget
{
Q_OBJECT
 
public:
cal(QWidget *parent = 0);
~cal();
 
private:
QPushButton *but1;
QPushButton *sub;
QPushButton *mul;
QPushButton *div;
QPushButton *eq;
QFormLayout *lay;
QLineEdit *line;
QString str;
QString str1;
QString ch;
QString strResult;
private slots:
void addi();
void subs();
void mult();
void divi();
void em();
public:
float num;
float num1;
float ans;
};
 
#endif // CAL_H

Código fonte

cal.cpp

#include "cal.h"
 
cal::cal(QWidget *parent)
: QWidget(parent)
{
lay=new QFormLayout(this);
but1=new QPushButton("+",this);
sub=new QPushButton("-",this);
mul=new QPushButton("*",this);
div=new QPushButton("/",this);
eq=new QPushButton("=",this);
line=new QLineEdit(this);
line->setMaxLength(12);
lay->addWidget(line);
lay->addWidget(but1)
lay->addWidget(sub);
lay->addWidget(mul);
lay->addWidget(div);
lay->addWidget(eq);
setLayout(lay);
QObject::connect(but1,SIGNAL(clicked()),this,SLOT(addi()));
QObject::connect(sub,SIGNAL(clicked()),this,SLOT(subs()));
QObject::connect(mul,SIGNAL(clicked()),this,SLOT(mult()));
QObject::connect(div,SIGNAL(clicked()),this,SLOT(divi()));
QObject::connect(eq,SIGNAL(clicked()),this,SLOT(em()));
}
 
cal::~cal()
{
// No need to delete any object that got a parent that is properly deleted.
 
}
void cal::addi()
{
str=line->text();
num=str.toFloat();
ch=but1->text();
line->clear();
}
void cal::subs()
{
str=line->text();
num=str.toFloat();
ch=sub->text();
line->clear();
}
void cal::mult()
{
str=line->text();
num=str.toFloat();
ch=mul->text();
line->clear();
}
void cal::divi()
{
str=line->text();
num=str.toFloat();
ch=div->text();
line->clear();
}
void cal::em()
{
 
 
str1 = line->text();
num1 = str1.toFloat();
if (ch=="+")
{
ans=num+num1;
}
else if(ch=="-")
{
ans=num-num1;
}
else if(ch=="*")
{
ans=num*num1;
}
else if(ch=="/")
{
ans=num/num1;
}
else
{
strResult = strResult.number(ans);
line->setText(strResult);
}
strResult = strResult.number(ans);
line->setText(strResult);
ch="";
}

Captura de tela

  • Entrada de algum valor na linha de edição.

Cal001.jpg

  • Operação decimal também é possível na calculadora.



Design da UI

QtCalculator.ui

QtCalculatorUi.png


Arquivo de cabeçalho

QtCalculator.h

#ifndef QTCALCULATOR_H
#define QTCALCULATOR_H
 
#include <QtGui/QWidget>
#include "ui_QtCalculator.h"
 
class QtCalculator : public QWidget
{
Q_OBJECT
 
public:
QtCalculator(QWidget *parent = 0);
~QtCalculator();
 
public slots:
void Addition();
void Subtraction();
void Multiplication();
void Division();
 
private:
Ui::QtCalculatorClass ui;
};
 
#endif // QTCALCULATOR_H


Código fonte

QtCalculator.cpp

#include "QtCalculator.h"
 
QtCalculator::QtCalculator(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this);
QObject::connect(ui.plusButton, SIGNAL(clicked()), this, SLOT(Addition()));
QObject::connect(ui.minusButton,SIGNAL(clicked()), this, SLOT(Subtraction()));
QObject::connect(ui.multiplyButton,SIGNAL(clicked()), this, SLOT(Multiplication()));
QObject::connect(ui.divisionButton,SIGNAL(clicked()), this, SLOT(Division()));
}
 
QtCalculator::~QtCalculator()
{
QString strFisrt = ui.lineEditNumber1->text();
QString strSecond = ui.lineEditNumber2->text();
 
bool ok;
int number1 = strFisrt.toInt(&ok);
int number2 = strSecond.toInt(&ok);
int result = number1 + number2;
 
QString strResult;
strResult = strResult.number(result);
ui.lineEditResult->setText(strResult);
}
 
void QtCalculator::Addition()
{
QString strFisrt = ui.lineEditNumber1->text();
QString strSecond = ui.lineEditNumber2->text();
 
bool ok;
int number1 = strFisrt.toInt(&ok);
int number2 = strSecond.toInt(&ok);
int result = number1 + number2;
 
QString strResult;
strResult = strResult.number(result);
ui.lineEditResult->setText(strResult);
}
 
void QtCalculator::Subtraction()
{
QString strFisrt = ui.lineEditNumber1->text();
QString strSecond = ui.lineEditNumber2->text();
 
bool ok;
int number1 = strFisrt.toInt(&ok);
int number2 = strSecond.toInt(&ok);
int result = number1 - number2;
 
QString strResult;
strResult = strResult.number(result);
ui.lineEditResult->setText(strResult);
}
 
void QtCalculator::Multiplication()
{
QString strFisrt = ui.lineEditNumber1->text();
QString strSecond = ui.lineEditNumber2->text();
 
bool ok;
int number1 = strFisrt.toInt(&ok);
int number2 = strSecond.toInt(&ok);
int result = number1 * number2;
 
QString strResult;
strResult = strResult.number(result);
ui.lineEditResult->setText(strResult);
}
 
void QtCalculator::Division()
{
QString strFisrt = ui.lineEditNumber1->text();
QString strSecond = ui.lineEditNumber2->text();
 
bool ok;
int number1 = strFisrt.toInt(&ok);
int number2 = strSecond.toInt(&ok);
int result = number1 / number2;
 
QString strResult;
strResult = strResult.number(result);
ui.lineEditResult->setText(strResult);
}


Conclusões

  • Será mostrada um simples calculadora na tela.

QtCalculatorScreenShot.png

Exemplo

Feedback

  • Se você econtrar algum problema na implementação desta simples calculadora, então por favor escreva seu feedback na página deste artigo Comment page (Inglês). Eu tentarei dá o máximo para tentar ajudar você.

Comentário

Código de erro resolvido.

This page was last modified on 11 October 2012, at 04:13.
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