How to present data in a list

[ogward]

Hi!
I have this "Line edit" and a "list View" now I would like to write something in the line edit and when I press enter I would like it to be displayed in the list view.
I've writen this small line but I have no Idea what I should write for index to be displayed in the list view.

void MainWindow::on_lineEdit_2_returnPressed()
{
    on_listView_entered(line1->text());
 
}
 
 
void MainWindow::on_listView_entered(QString index)
{
 
}

void MainWindow::on_lineEdit_2_returnPressed()
{
    on_listView_entered(line1->text());

}


void MainWindow::on_listView_entered(QString index)
{
    
}

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best regards

[Zlatomir]

To use QListView you need to use Model-View.

A simple method (that doesn't involve learning Model-View) is to use QListWidget class to display a list in a simple application.
//it is recommended to learn about Model-View, because it is used in many applications, it's a very useful design pattern.

[ogward]

thanks for the tip, what do I write to present it?

[helloworld]

Something like...

mainwindow.h:

#include <QtGui/QMainWindow>
 
class QLineEdit;
class QListWidget;
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
protected slots:
    void addItemToList();
 
private:
    QLineEdit   *m_edit;
    QListWidget *m_list;
};

#include <QtGui/QMainWindow>

class QLineEdit;
class QListWidget;

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

protected slots:
    void addItemToList();

private:
    QLineEdit   *m_edit;
    QListWidget *m_list;
};

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mainwindow.cpp:

#include <QListWidget>
#include <QLineEdit>
#include <QVBoxLayout>
#include "mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent),
      m_edit(new QLineEdit),
      m_list(new QListWidget)
{
    QWidget *widget = new QWidget;
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(m_list);
    layout->addWidget(m_edit);
    widget->setLayout(layout);
    setCentralWidget(widget);
 
    QObject::connect(m_edit, SIGNAL(returnPressed()),
                     this, SLOT(addItemToList()));
}
 
MainWindow::~MainWindow()
{
}
 
void MainWindow::addItemToList()
{
    m_list->addItem(m_edit->text());
}

#include <QListWidget>
#include <QLineEdit>
#include <QVBoxLayout>
#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent),
      m_edit(new QLineEdit),
      m_list(new QListWidget)
{
    QWidget *widget = new QWidget;
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(m_list);
    layout->addWidget(m_edit);
    widget->setLayout(layout);
    setCentralWidget(widget);

    QObject::connect(m_edit, SIGNAL(returnPressed()),
                     this, SLOT(addItemToList()));
}

MainWindow::~MainWindow()
{
}

void MainWindow::addItemToList()
{
    m_list->addItem(m_edit->text());
}

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[ogward]

omg that looks extremely complicated...

The thing is today is the first time I've ever opened Qt so I don't know squat...
I have this console based app I've written in visual studio that I would like to "connect" to the most basic gui in the easiest way possible and I've heard that qt is the way.

could anyone here give me some pointers?

[ogward]

Ok so I changed to QlistWidget and now I would like to make a function that checks my array (Test**test) and converts all std::strings to QStrings.

void Diet::toQString()const
{
 
    QString qName(this->name.c_str());
    QString qUserName(this->userName.c_str());
    QString qDate(this->date.c_str());
    //have an int this->kcal
    //and have three doubles this->protein, this->carb, this->lipid
 
 
}

void Diet::toQString()const
{

    QString qName(this->name.c_str());
    QString qUserName(this->userName.c_str());
    QString qDate(this->date.c_str());
    //have an int this->kcal
    //and have three doubles this->protein, this->carb, this->lipid
    

}

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now I have no idea if this is even remotely correct but at least I tried something.

what I want this function to do is when I call it in listWidget it should present the info from the array from a certain slot.

[Zlatomir]

Why don't you use QString from begin to end?

Anyway QString has some static functions like fromStdString you can use to create QString from std::string.
Also QString has ways to construct QStrings from int, check the QString documentation.

[ogward]

what do you mean by from beginning to end?
why I have std::string?

[Zlatomir]

I mean to use QString instead of std::string all over the place (so that you don't need to convert strings)

[ogward]

Yeah I could do that, but then I have to change every single std::string to a QString and I'm almost sure that something will f*** up in the process.
You think thats the easiest way? easier than only to have a function that converts all strings to QStrings?

[Zlatomir]

Well it is easier with conversion, but conversion means a copy of the string and if you have a lot of strings, and that lot increases, at some point that conversion might not be acceptable any more.

But if your number of conversions is low the performance penalty is also low.

//but for a new project you can use QString from the beginning and see that QString has many more features than std::string, so it may be easier to use.

[ogward]

ok, thanks for the tip.
What do you think about the function I posted above? Is that conversion working? and what can I write inside that function if I want all the data to be presented in a window.
I mean if I wanted to do that in VS I would only write cout but what about now?

[Zlatomir]

You can still use cout to print QString to console with the help of qPrintable or you can use qstringName.toLocal8Bit().constData();
Or you can use qDebug()

[ogward]

But if I dont want to print it in the console? I want it to be printed out in the QListWidget.

[Zlatomir]

Then use addItem(...)

[ogward]

I have these two

private:
    Ui::MainWindow *ui;
    QLineEdit *line1;
    QListWidget *list1;

private:
    Ui::MainWindow *ui;
    QLineEdit *line1;
    QListWidget *list1;

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and these two functions

void MainWindow::on_lineEdit_2_returnPressed()
{
    on_listWidget_activated(line1->text());
 
}
 
void MainWindow::on_listWidget_activated(QString index)
{
    list1->addItem(index);
 
}

void MainWindow::on_lineEdit_2_returnPressed()
{
    on_listWidget_activated(line1->text());

}

void MainWindow::on_listWidget_activated(QString index)
{
    list1->addItem(index);

}

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but when I run it and type into the lineEdit and push enter nothing happens

[tbscope]

Why don't you do yourself and every one else a favor and start with reading some documentation.

I think you might want to start with the Qt basics like signals and slots.

[ogward]

yeah I understand that but I think that the thing I want to accomplish is not that complicated, so I just need a push in the right direction.
If I know how to catch data from a line and present some data in a window then I think I can figure out everything else by my self cos I believe its just basic c++ after that.