@Jarenward said in Fresh app development:

which Qt is for me?

There is only one Qt :-)
PyQt is a Python binding for Qt and still requires Qt libraries (binaries). So, even if you use PyQt you will need to have Qt libraries which you are using.
If I understood you correctly you need your UI on a computer (not Pi), right? This part is simple - just install the latest stable Qt version an start coding :-)
For the other part you can either directly develop on Pi (using Raspbian you can easily install Qt with apt) or you have to cross compile Qt to develop on your PC. You don't have to cross compile everything, just what you need. See https://wiki.qt.io/Raspberry_Pi_Beginners_Guide

@Ovidiu_GCO
{SQL Server Native Client 17.0 };
What is with the blank in front of "}"

Thanks for the answers, I found the connection problem. I added the part:

void MainWindow::on_connectType_currentIndexChanged(int index)
{
if (modbusDevice) {
modbusDevice->disconnectDevice();
delete modbusDevice;
modbusDevice = nullptr;
}

auto type = static_cast<ModbusConnection> (index); if (type == Serial) { modbusDevice = new QModbusRtuSerialMaster(this); } else if (type == Tcp) { modbusDevice = new QModbusTcpClient(this); if (ui->portEdit->text().isEmpty()) ui->portEdit->setText(QLatin1Literal("127.0.0.1:502")); } connect(modbusDevice, &QModbusClient::errorOccurred, [this](QModbusDevice::Error) { statusBar()->showMessage(modbusDevice->errorString(), 5000); }); if (!modbusDevice) { ui->connectButton->setDisabled(true); if (type == Serial) statusBar()->showMessage(tr("Could not create Modbus master."), 5000); else statusBar()->showMessage(tr("Could not create Modbus client."), 5000); } else { connect(modbusDevice, &QModbusClient::stateChanged, this, &MainWindow::onStateChanged); }

}

And now I can make a connection.

Now I have to test it on the device, but i can't access it for a while, to be continued

@VRonin Excellent! This is exactly what I was looking for! Thank you!

No worries for that :)

Since you have it working now, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)

Hi @kahlenberg,

I am newbee for Qt, I have found very useful page on https://wiki.qt.io/Qt_for_Beginners but it seems it is only for Qt 4.8, for example
in the very first code example it says #include <QApplication>, but in Qt 5.5 it is #include <QtCore/QCoreApplication>.

Qt 5.5 uses #include <QApplication> too.

Scroll down the wiki article, and you'll see the line greaterThan(QT_MAJOR_VERSION, 4): QT += widgets. Add this, and the article should work for Qt 5.5. (However, I would still recommend an official guide, instead of the wiki).

Where can I find "new and fresh" tutorial for beginners for Qt 5.5?

You can find an official beginners' guide at http://doc.qt.io/qt-5/gettingstartedqt.html

Now i have better understood the dynamics of connect.

Thanks for your patience.

Then it's just a matter of removing from the list items that are already added. Something like this:

//get the list from somewhere QStringList fileNames = ... //remove the temp item you mentioned fileNames.removeOne(temp); //remove the items already in the widget int numItems = listWidget->count(); for(int i = 0; i < numItems; ++i) fileNames.removeOne(listWidget->item(i)->text()); //now that the list is "clean" all there is left to do is add the new items listWidget->addItems(fileNames);

Welcome to the world of Qt :) Happy coding!

@Chris-Kawa

Thank you very much!

@mcosta Hi,

I'll certainly take a look at it. So I guess it's not only changing the font xD

Thank you.

Since you talked about QML I will assume that you work with embedded devices so SQLite is probably the database for you.
Here is an example of how to connect to a database, hope this helps:

QSqlDatabase db = QSqlDatabase::addDatabase("SQLITE"); db.setDatabaseName("path/to/database.db"); db.open(); //This will create the database if it doesent exist

Make sure to include

#include <QSqlDatabase>

Also add

QT += sql

To your project file

Thanks a lot for your pointers (no pun intended :-)

If you want to do it widget style you might be interested by this

Otherwise, are you going to use QML ?