QT Framework Overview

Qt is a powerful cross-platform application framework used for developing GUI (Graphical User Interface) applications Qt provides various tools, libraries, and APIs for building applications that can run on multiple platforms, including Windows, macOS, Linux, Android, and iOS.

Qt has its "write once, run anywhere" philosophy, which allows developers to write code once and deploy it on different platforms without significant modifications. Qt has this cross-compatible feature set.

Qt's architecture is based on the concept of signals and slots, which enables easy communication between different components of an application both between the C++ backend parts and with the frontend Code components.

Many times we get confused about the different QT tools and terms because maybe they all start with Qt. I have made the following table can help you have some more information in this regard

.ui format	Ui file is the old format for designing desktop GUI App	It is the older QT Gui file format
.qml format	QML is the new format to design cross platform applications . materialistic design	QML is kind if of a programming language
QtQuick	Qt Quick is a software framework holding buttons , text fields etc	QML is the language to work with Qt Quick
Qt Designer	This is a graphical tool to make ui file	Ui file is older Qt Widget desktop application type
Qt Design Studio	Can work with both .qml and .ui format file	Previously it was known as Qt Quick Designer
QtCreator	It is an IDE where you can write both C++ code and it has Design options to work on QML and ui file  It is used for creating a project out of QT SDK versions  You need to Link a SDK to Creator IDE	But there are dependencies for example using QtCreator 11 you cannot create a project targeting Qt SDK version 5.14 . You need to use QtCreator 4.14 for that
QT SDK	This is the main SDK . it has different versions	For example QT 5.14 SDK
QT Maintenance Tool	You can use this to add/remove/update all the above components	To use it you need an online registration

QT Widget vs QML 

widget is powerful for native classic desktop applications and QML is for overall all platforms . Qt Creator IDE itself is created using Qt Widgets .

Qt Widget file format is ui format and can be designed using Qt Designer .

QT Creator Examples

There are a lot of QML examples in QT Creator.Search by QML and you will find many

In QTCreator you can enable QT Design option in the following way. Afterwards you can design QML in QT Creator IDE itself .

With QML, you can create rich, dynamic UIs using a declarative syntax that's more intuitive

Moreover, QML seamlessly integrates with Qt's C++ backend, enabling you to leverage the full power of the Qt framework while benefiting from the flexibility and agility of QML for UI design.

Additionally, QML offers excellent support for different user interfaces that can easily scale across different screen sizes and orientations on a wide range of devices, from smartphones and tablets to desktops and embedded systems Displays.

So if you're starting a new Qt project or considering migrating an existing one, embracing QML would be the Ideal choice