Sure, here is a detailed tutorial on "Creating Basic GUI Applications with Qt".

1. Introduction

In this tutorial, we aim to introduce you to the creation of basic GUI applications using Qt, a cross-platform application framework. By the end of this tutorial, you should be able to:

• Understand the fundamentals of Qt.
• Design a simple GUI using Qt.
• Write the application logic.
• Handle basic user events.

Prerequisites

Before starting, you should have a basic understanding of C++ programming. Familiarity with object-oriented programming concepts would also be helpful. Also, you need to install the Qt framework and the Qt Creator IDE on your computer.

2. Step-by-Step Guide

Setup and Basic Concepts

After installing the Qt framework and Qt Creator IDE, start a new project by selecting "Application" -> "Qt Widgets Application".

Qt applications are typically written in C++, using the Qt toolkit's interfaces and classes. The main building blocks of Qt applications are QObjects, which provide a framework for event handling, signals, slots, properties, and more.

Designing the Interface

Once you've created your project, you can start designing your UI using the Qt Designer. You can drag and drop widgets (like buttons, text fields, etc.) from the widget box onto the form. For instance, you can add a QPushButton and a QLineEdit to create a simple interface with a button and a text field.

Writing Application Logic

To add functionality to your UI elements, you'll need to write some application logic. For example, if you want to show a message when the button is clicked, you would do something like this:

connect(ui->myButton, SIGNAL(clicked()), this, SLOT(showMessage()));

Here, connect is a function that connects a signal (the button being clicked) to a slot (a function that will be called when the signal is emitted).

3. Code Examples

Here's a simple example of a Qt application that shows a message when a button is clicked.

#include <QApplication>
#include <QMessageBox>
#include <QPushButton>

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

    QPushButton button ("Click me!");
    QObject::connect(&button, &QPushButton::clicked, [&]() {
        QMessageBox::information(nullptr, "Clicked", "You clicked the button!");
    });
    button.show();

    return app.exec();
}

When you run this code and click the button, you'll see a message box that says "You clicked the button!".

4. Summary

In this tutorial, you've learned how to create a basic Qt application, design a simple interface, write application logic, and handle user events. The next steps would be to learn more about Qt's advanced features, like layouts, model/view programming, and more.

5. Practice Exercises

1. Create a Qt application with a text field and a button. When the button is clicked, show the text from the text field in a message box.
2. Create a Qt application with two text fields and a button. When the button is clicked, show the sum of the numbers entered in the text fields in a message box.
3. Create a Qt application with a list box and a button. When the button is clicked, add the current time to the list box.

Remember, the key to mastering Qt (or any other framework) is practice. Happy coding!