Basic:

1. What is Qt?
- Qt is a comprehensive C++ framework that enables developers to
create applications with a single codebase that can run across various
platforms, including Windows, macOS, Linux, Android, and iOS.

2. Explain the difference between Qt Widgets and Qt Quick.

- Qt Widgets: This module provides traditional UI components like
buttons, labels, and input fields. It's ideal for desktop-style applications.
- Qt Quick: Utilizes QML, a declarative language, to build modern, fluid
UIs with animations and effects. It's well-suited for mobile and touch-
based interfaces.

3. How does Qt manage events?

- Qt follows an event-driven architecture where events like mouse
clicks or key presses are handled by objects through event handlers or
filters.

4. What are the basic building blocks of a Qt application?

- QObject: The base class for Qt objects, providing features like signals
and slots.
- QWidget: The base class for GUI elements in traditional applications.
- Signals and Slots: A mechanism for inter-object communication.
- QApplication: The main application object handling control flow.
 - Layouts: Used to arrange widgets within containers.

5. Describe the role of signals and slots in Qt.

- Signals and slots enable communication between objects in Qt. A
signal is emitted when an event occurs, and a slot is a function that
responds to that event.

6. What is QML in Qt?

- QML (Qt Modeling Language) is a declarative language used to
design UIs in Qt Quick applications. It provides a way to create and
organize visual items and define their behaviors.

7. Explain the concept of QObject in Qt.

- QObject is the base class for all Qt objects. It provides functionalities
like object name, dynamic properties, signals and slots, and memory
management.

8. How does Qt manage memory?

- Qt manages memory through a parent-child hierarchy. When an
object is assigned a parent, it becomes the responsibility of the parent
to manage the child's memory.
9. What are the main advantages of using Qt for application
development?
- Cross-platform support, a rich set of libraries and tools, strong
community support, and a comprehensive set of functionalities are
some of Qt's key advantages.

10. What is the Qt Resource System?

- The Qt Resource System allows developers to embed external files
(like images or XML) within the application's executable, simplifying
access and distribution.
11. Describe the role of QApplication in a Qt application.
- QApplication manages the application's control flow and main
settings. It handles the event loop, system events, and application-wide
configurations.

12. Discuss the use of QTimer in Qt applications.

- QTimer provides a mechanism to trigger events at regular intervals.
It's often used for tasks like updating UI elements or performing
periodic operations.

13. How are signals and slots connected in Qt?

- Signals and slots are connected using QObject's connect() method.
The connect() function links a signal from one object to a slot in
another, allowing communication between them.
14. What is the QObject::property() method used for in Qt?
- QObject::property() retrieves the value of a dynamic property set on
a QObject. Dynamic properties allow attaching additional metadata to
objects at runtime.

15. Explain the concept of QObject's meta-object system.

- The meta-object system in Qt enables features like signals and slots,
introspection, dynamic properties, and type information at runtime,
enhancing the capabilities of QObject-derived classes.

Intermediate:
1. Describe the Model-View-Controller (MVC) architecture in Qt.
In Qt, the Model-View-Controller (MVC) pattern separates data
(Model), its representation (View), and user interaction
(Controller). QAbstractItemModel and QAbstractItemView are
key components.

2. Explain the role of layouts in Qt Widgets.

Layouts in Qt Widgets help automatically manage the
positioning and resizing of widgets within containers, ensuring
consistent and adaptable UIs.
3. What is the purpose of QVariant in Qt?
QVariant is a type-safe union for handling Qt's data types. It
provides a generic container that can hold values of different
types.

4. How does Qt handle internationalization and localization?

Qt supports internationalization and localization through the
use of Qt Linguist, allowing developers to create applications
that can be easily translated into different languages.

5. Discuss the differences between Qt's QPainter and QML's Canvas.

QPainter is used in QWidget-based applications for drawing 2D
graphics, whereas QML's Canvas provides similar drawing
capabilities within Qt Quick applications using a declarative
approach.

6. Explain the concept of Qt Stylesheets.

Qt Stylesheets provide a mechanism to customize the
appearance of widgets by applying styles similar to CSS,
allowing developers to change colors, fonts, and other visual
attributes.
7. What is the event loop in Qt, and how does it work?
The event loop is the core mechanism in Qt that continuously
checks for events like user input or system notifications and
dispatches them to appropriate objects for handling.

8. Discuss the usage of Qt's model/view classes like

QAbstractItemModel.
QAbstractItemModel provides an abstract interface to data that
can be displayed and edited by views without knowing the
underlying data source, enabling separation of data and
presentation.

9. Explain the role of Qt's moc (Meta-Object Compiler).

moc generates additional C++ code for classes that use Qt's
meta-object system, enabling features like signals and slots,
introspection, and dynamic properties.

10. How does Qt support multi-threading?

Qt provides thread support through classes like QThread and
QtConcurrent, enabling developers to create and manage
threads and handle communication between them.
11. How does Qt handle the integration of 3D content and rendering?
- Qt6 introduced Qt 3D Studio for creating rich 3D user interfaces and
interactive applications. It offers a visual editor and integrates with Qt
Quick.

12. Discuss the usage of QtCharts for data visualization.

- QtCharts is a module providing APIs to create interactive and
customizable charts. It supports various chart types and allows easy
integration into Qt applications.

13. Explain the role of Qt Quick Compiler in optimizing QML

performance.
- Qt Quick Compiler compiles QML files into C++ code, improving
runtime performance by eliminating the need for QML interpretation
and reducing load times.

14. How does Qt handle multimedia functionalities such as audio and

video playback?
- Qt Multimedia module provides APIs to handle multimedia
functionalities like audio and video playback, camera access, and
multimedia streaming.
15. Describe the usage of QtLocation for integrating mapping and
location-based services.
- QtLocation provides access to mapping and positioning features,
allowing developers to integrate maps, geocoding, and navigation
functionalities into their applications.

16. Discuss the role of QtSerialBus in working with industrial serial

buses.
- QtSerialBus offers classes to communicate with industrial serial
buses like CAN bus, Modbus, and others, facilitating communication
with industrial devices.

17. Explain the concept of Qt Remote Objects for inter-process

communication.
- Qt Remote Objects enables inter-process communication by
allowing objects residing in different processes or devices to interact
transparently using Qt's meta-object system.

18. How does Qt support gesture recognition and touch input?

- Qt provides gesture recognition APIs and touch event handling to
support multi-touch and gesture-based interactions in applications
across different platforms.
19. Discuss the usage of Qt's Bluetooth module for device connectivity.
- Qt's Bluetooth module provides APIs to enable Bluetooth
communication, allowing applications to connect and communicate
with Bluetooth-enabled devices.

20. Explain the process of integrating Qt applications with machine

learning frameworks.
- Qt offers integration possibilities with various machine learning
frameworks like TensorFlow or ONNX by allowing the use of C++ APIs
and libraries.

Advanced:
1. Discuss the changes introduced in Qt6 compared to previous
versions.
- Qt6 brought several enhancements including improved modularity,
better C++ support, removal of deprecated APIs, and performance
improvements.

2. Explain the usage of Qt Quick Controls 2 and their advantages over Qt

Widgets.
- Qt Quick Controls 2 offer a set of pre-designed UI controls optimized
for touch-based interfaces, providing better performance and modern
UI elements compared to Qt Widgets.
3. Describe the process of creating custom QML components.
- Custom QML components are created by defining new types or
extending existing ones using QML syntax, allowing developers to build
reusable components.

4. How does Qt handle platform-specific functionality and cross-

platform development?
- Qt uses the Qt Platform Abstraction (QPA) layer to abstract platform-
specific code, allowing developers to write cross-platform applications
with minimal platform-specific code.

5. Discuss the role of Qt Concurrent in handling concurrent

programming.
- Qt Concurrent provides high-level APIs for parallel programming,
making it easier to write multi-threaded applications by managing
concurrent tasks and synchronization.

6. Explain the performance differences between using QGraphicsView

and Qt Quick for complex UIs.
- Qt Quick tends to offer better performance for complex UIs due to
its use of hardware-accelerated rendering and modern graphics
techniques compared to QGraphicsView.
7. Describe the use of Qt's networking classes for TCP/IP
communication.
- Qt provides classes like QTcpSocket and QNetworkAccessManager
for handling TCP/IP communication, making it straightforward to
implement network functionality in applications.

8. Explain the process of integrating C++ code with QML.

- C++ code can be integrated with QML by exposing C++ classes to
QML using QObject-derived types, allowing interaction between QML
and C++ through signals, slots, and properties.

9. Discuss the mechanisms provided by Qt for handling database

operations.
- Qt provides the Qt SQL module with classes like QSqlDatabase and
QSqlQuery to interact with databases, supporting various database
engines and facilitating database operations.

10. How does Qt6 support modern C++ features?

- Qt6 embraces modern C++ standards by adding support for new C++
features like lambda expressions, constexpr, and enhanced support for
C++11 and beyond.
11. Discuss the use of Qt Virtual Keyboard for on-screen input.
- Qt Virtual Keyboard provides a fully customizable on-screen
keyboard solution, suitable for touch-based devices and platforms
where a physical keyboard is not available.

12. Explain the role of QtWebEngine for web content integration.

- QtWebEngine allows integration of web content by providing APIs to
embed web pages or web-based applications using the Chromium-
based browser engine.

13. Describe the process of deploying Qt applications on mobile

platforms.
- Qt applications for mobile platforms can be deployed using Qt's
build tools like qmake or CMake, creating packages compatible with app
stores or sideloading.

14. Discuss the use of Qt Sensors for accessing device sensors.

- Qt Sensors module provides APIs to access various sensors like
accelerometer, gyroscope, compass, etc., enabling developers to utilize
device sensor data in applications.
15. Explain the purpose of Qt MultimediaWidgets for multimedia
playback.
- Qt MultimediaWidgets module offers widgets for multimedia
playback controls, facilitating the integration of multimedia
functionalities within the UI.

16. How does Qt handle accessibility features for differently-abled

users?
- Qt supports accessibility features by providing APIs to assistive
technologies, ensuring applications are accessible to users with
disabilities.

17. Discuss the usage of Qt Quick Compiler for optimizing QML

performance.
- Qt Quick Compiler translates QML files into C++ code, improving
runtime performance by precompiling QML resources, reducing startup
times, and optimizing execution.

18. Explain the role of Qt Network Authorization for OAuth-based

authentication.
- Qt Network Authorization module provides support for OAuth-
based authentication flows, enabling secure authentication and
authorization mechanisms in Qt applications.
19. Describe the use of Qt Speech for text-to-speech and speech
recognition.
- Qt Speech module offers APIs to perform text-to-speech and speech
recognition functionalities, allowing integration of speech-related
features into applications.

20. How does Qt support integration with other development

frameworks or tools?
- Qt supports integration with various third-party tools and
frameworks through APIs, libraries, and plugins, enabling collaboration
and extension of functionalities.