Save Input Text to File through Button Click

[bill725]

This is the only file my program has called main.cpp

When I build and run it, it displays my two text input fields. I want to type into them, click the button and have the text save to a file. How can I go about doing this?

@//! [main program]
#include <QtWidgets>
#include <QPushButton>
#include <QObject>

void main::example(){

}

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget window;
//! [create, lay out widgets and show]
//This line created a label that says Longitude
QLabel *pointOneLongLabel = new QLabel(QApplication::translate("windowlayout", "Longitude:"));
//This line creates a text input where the user can type into. It will be used to type in the longitude.
QLineEdit *pointOneLongInput = new QLineEdit();

//The following pairs of lines are the same as above.  It is creating a label and textinput for
//each of the points (longitude and latitude we will navigate to.

QLabel *pointOneLatLabel = new QLabel(QApplication::translate("windowlayout", "Latitude:"));
QLineEdit *pointOneLatInput = new QLineEdit();



//This is going to create a new clickable button that will read "Apply"
QPushButton *button = new QPushButton();
button->setText("Apply");

//This line will make the button do something.
QObject::connect(button, SIGNAL(clicked()),window ,SLOT(fun()));


//QString textinlineedit;
//textinlineedit = lineEdit ->text();

//This line creates a new layout in the window
QHBoxLayout *layout = new QHBoxLayout();
//These lines add our objects (labels, input boxes, buttons) to the layout.
layout->addWidget(pointOneLongLabel);
layout->addWidget(pointOneLongInput);
layout->addWidget(pointOneLatLabel);
layout->addWidget(pointOneLatInput);

layout->addWidget(button);

window.setLayout(layout);

//! [create, lay out widgets and show]
window.setWindowTitle(
QApplication::translate("windowlayout", "Enter Waypoints"));
window.show();
return app.exec();
}
//! [main program]
@

[stevenceuppens]

Hi Bill,

If you really want to keep everything in the main function, Lambda (Qt5 & C++11) can be used here...

Add this to your .pro file to enable c++11:
@
CONFIG += c++11
@

Example code:
@
#include <QtWidgets>
#include <QPushButton>
#include <QObject>
#include <QDebug>

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

// setup QFile, argument is path to file (relative from executable)
QFile data("output.txt");
// open file
if (!data.open(QFile::WriteOnly | QFile::Truncate)) {

    qDebug() << "Can't open file";

    return 1;
}
// attach file to QTextStream
QTextStream out(&data);


QWidget window;

//! [create, lay out widgets and show]
//This line created a label that says Longitude
QLabel *pointOneLongLabel = new QLabel(QApplication::translate("windowlayout", "Longitude:"));
//This line creates a text input where the user can type into. It will be used to type in the longitude.
QLineEdit *pointOneLongInput = new QLineEdit();

//The following pairs of lines are the same as above.  It is creating a label and textinput for
//each of the points (longitude and latitude we will navigate to.

QLabel *pointOneLatLabel = new QLabel(QApplication::translate("windowlayout", "Latitude:"));
QLineEdit *pointOneLatInput = new QLineEdit();



//This is going to create a new clickable button that will read "Apply"
QPushButton *button = new QPushButton();
button->setText("Apply");

//This line will make the button do something.
// using Lambda (Qt5 && c++11 only)
QObject::connect(button, &QPushButton::clicked, [&out, pointOneLongInput, pointOneLatInput]() {

    // stream data to QTextStream
    out << "Result: " << pointOneLongInput->text() << "," << pointOneLatInput->text() << endl;
});


//QString textinlineedit;
//textinlineedit = lineEdit ->text();

//This line creates a new layout in the window
QHBoxLayout *layout = new QHBoxLayout();
//These lines add our objects (labels, input boxes, buttons) to the layout.
layout->addWidget(pointOneLongLabel);
layout->addWidget(pointOneLongInput);
layout->addWidget(pointOneLatLabel);
layout->addWidget(pointOneLatInput);

layout->addWidget(button);

window.setLayout(layout);
//! [create, lay out widgets and show]
window.setWindowTitle(QApplication::translate("windowlayout", "Enter Waypoints"));
window.show();
return app.exec();

}
@

But in would advice to move QWidget window, to its own class / file where you easily can make signal - slot connections

[bill725]

Thank you so much Steven! That worked like a charm, I know that it is poor programming practice to have a file that does multiple things and that I should have a class for each feature I need to implement but I was using an example template that was almost completely functional and just needed to add that small piece. Thanks again!

[stevenceuppens]

No problem!

Keep on Qt ;)