New to Qt. In the official Qt tutorial, it says:
To set up a project, you first have to decide what kind of an application you want to develop: do you want a user interface based on Qt Quick or HTML5 or Qt widgets.
We plan to use Qt to do medical image display, and also use Qt to build a GUI application to control a medical device. They will be two different projects.
Which Qt project type we should use for them?
Docs say:
QWidgets are a better choice if your UI is comprised of a small number of complex and static elements, and QML is a better choice if your UI is comprised of a large number of simple and dynamic elements.
I say:
If you're going for desktop applications I'd suggest Qt Widgets, you don't have to ship the final app with libs for QML and the whole source will be written in C++ (faster, simplier so easier to debug).
QML would be a nice alternative if you want to create phone/tablet (touch experience in general).
I would argue that between Qt Quick and Qt Widgets there is no objectively right answer. In theory, one should be able to replicate any UI using either method - because at the end of the day, they are both using QtGui behind the scenes. So functionality is probably not an issue.
One thing to note is that Qt Quick (i.e., QML) is designed explicitly to make UI programming require much less code, and much less C++ knowledge. I would say it achieves this goal very well.
However, at the end of the day, I think it mostly comes down to what language your developers are already familiar with. If you have a team of C++ pro's, then I would go with Qt Widgets - if only because it's going to be very easy for them to pick up, and it's something they're already familiar with. (I'm guessing this is the case because you're already writing C++ code for your project).
If, on the other hand, your developers are already very good at QML (or, more generally, JavaScript - which QML is heavily influenced by), then I would go with Qt Quick for the same reasons.
I know of two types of Qt UI: Qt Quick and widgets.
Widgets behave like most other UI toolkits out there, you have a GUI editor and a tree of UI objects. They are pretty mature and look like most standard UIs.
Qt Quick is the newer Qt UI toolkit. It uses a domain specific declarative language (QML) to specify the user interface and JavaScript for interactions. There are also plans to offer Qt widgets inside the Qt Quick framework, but I'm not sure how far that project has gotten. Qt Quick is meant to deliver more dynamic / custom user interfaces.
As far as I know Qt will continue to support both approaches in the foreseeable future so which one you pick depends on your use-case.
Related
the QT widget is very time consuming in terms of UI development, my CSS sheets has 3000 lines of code already and it is very time consuming to do UI changes. My application is very demanding in terms of performance, I was thinking of embedding the widgets into QML to have easier and faster control of the UI but I'm really worried about performance, will worth the try or it is just bad practice?
My application is very demanding in terms of performance, I was
thinking of embedding the widgets into QML to have easier and faster
control of the UI but I'm really worried about performance, will worth
the try or it is just bad practice?
Since Qt 5.1 we can easily embed QML view to Qt Widget container. There is a blog I stumbled upon some time ago: Combining Qt Widgets and QML with QWidget::createWindowContainer().
As for performance, unsure what kind of performance is in demand for your application? Overall QML renders to screen via OpenGL or very fast. On the other hand with QML you often need to deal with JavaScript which of course is not comparable to C++. There is Qt Quick Compiler introduced to commercial Qt, though.
As for QWidget-based UI vs. QML: the discussion can be considered an expression of opinion etc. Some consideration points then:
Developing and maintaining one kind of UI, either widget or QML based is easier.
Hybrid UI is possible but it makes sense to understand what you can gain from it.
Most desktop apps are fully satisfied with widgets only.
When the app supposed to be ported to mobile platforms as well then QML makes more sense.
When the app supposed to rely on 'touch' then QML is also more beneficial than widgets.
the QT widget is very time consuming in terms of UI development, my
CSS sheets has 3000 lines of code already and it is very time
consuming to do UI changes.
Hmm... very heavily styled widget-based app? I can only be sure that these two concepts: widgets and QML are very different but both widget stylesheets and QML are declarative language though different. I am also sure that any serious app needs more of C++ and with QML we need to spend time bridging C++ code with QML.
And the distribution of QML apps can also be a bit more complex than purely widget-based: for instance you need to customized Qt build to support OpenGL emulated for certain VMs and platforms: that is one interesting topic. Also with Qt Quick widgets you use should put them either to resource distributed with the app or you need Qt Quick Compiler. And if you use it, be sure that all QML code was compiled by it and no part of the app still uses 'scripted' QML which is missing from resources. I made use of Qt 5.5 Quick Compiler in our app and found not only quite a few bugs with it but also still needs to drag certain Qt Quick files from framework together with the app install package. That is not as bad with standard dynamic link and windeployqt tool. But a serious app often needs to be statically linked with all its dependencies and then we cannot use windeployqt tool.
Overall Qt is departing from widgets to QML but what can we gain and how much we need QML in our real applications is a long discussion.
I've just started learning Qt recently, finding QML quite interesting for implementing UI component. Before the project really kick off, I've got some questions:
For a fresh start project, should I just use QML? Does QML be designed for replacing QWidget?)
If I go with QML, is there anything else must be implemented with C++? Or better implemented with C++ for better performance? (I know some customized UI components can be integrated through plugin) What's the relationship between QML and C++ widget?
As for performance or rendering issue, does QML better than native C++ widget?
When you start a question with 'Should I use', it is quite a good hint that SO might not be the right place to ask it. Even more when there are only answers, which start with 'It depends on...'.
QML is not designed to replace QWidget. It is a different technique. Which one to use, depends on your requirements.
Whether or not you must implement additional stuff in C++ depends on your project. Some things are easier in C++, others in QML. And some stuff is not possible in QML at all.
There is no relationship between QML and C++ widgets.
And the performance of QML is in most cases more than sufficient. In almost every case QML is used to create user interfaces. I doubt that there are many cases where clicking a button or opening a dropbox folder is performance critical.
I had a chance to put this question to a few Qt experts at the World Summit today and the general take was that because QML component rendering can be done through hardware acceleration that it is preferred for apps requiring high performance graphics, eg automotive dashboards. OTOH widgets seem to be used for desktop applications. Another consideration is that while widgets can be styled using Qss (Qt's version of Css), QML components cannot.
In QML based applications computationally intensive functions are generally written in C++.
HTH,
Eric G
I am an iOS / Cocoa developer looking to port one of my apps to PC platform. I don't care to code multiplatform and maintain one app. I will continue using cocoa and cocoa touch for iOS Mac Development.
I have chosen to use QT 5 for PC, I am not sure if its wise choice but its easy and I can understand c++. If its not please point me to the correct direction.
My App is not hugely complicated, but needs some special customization e.g. ListView that looks like an iOS Table View, uses custom rounded windows with twitter bootstrap style search box and I want to monitor some global OS events like keystrokes, and what other applications the user is currently working with. I also use SQLite and AES encryption.
My questions is regarding UI customization.
Should I start studying and use QML for that? I am not sure what exactly it is, seems extremely simple CSS like, but I have the feeling is more designed for embedded devices and have limitations...
Do I have access to the entire power of QT if I use QML ?
What other options I have to customise widgets instead using QML (e.g. in objective C we use subclassing and drawing whatever we want or handling events...)
I am inexperienced in windows platform. Should I use VisualStudio C++ instead of QT5? With the changes in ownership I feel somehow insecure.
Yes you should. QML is declarative language which allows javascript to be executed within it. And you can do almost anything UI related with QML. If you don't have some particular UI element you can draw it in plain C++(Qt) and use it in the QML. So QML is the best choice for Qt development at the moment. It is not like CSS though, it is much more powerful.
Yes you have all the power Qt has and additional power which declarative language may offer - simplification of UI development process as well as modern decomposition of UI&logic.
You have this option in plain C++ Qt, you may subclass widget, redraw them, change behavior etc. This approach is inferior to the QML one.
This point doesn't make sense. Some people count Visual C++ like separate language which is wrong. You may count Visual C++ as C++ + some minor extensions MS compiler has. But it is as ridiculous to refer as GCC C++. So basically you can use Visual Studio with Qt almost without a pain if you use Qt integration add-in which is freely available. Or you can choose Qt creator, which some people count as superior to MSVS. It is up to you what to choose, but I believe for the novice it is much simpler to use Qt creator with Qt. But note you will need to have some compiler because Qt creator is just an IDE it should use some 3rd party compiler(either MS or GNU one)
You can use QML Desktop Components to build easily your application:
https://web.archive.org/web/20121203050945/http://blog.qt.digia.com/blog/2012/06/06/desktop-components-for-qt-5/
http://qt-project.org/wiki/Qt_Quick_Components
Anyway I recommend you use Qt Widgets and Qt Style Sheets to costume your widgets:
http://qt-project.org/doc/qt-4.8/stylesheet-reference.html
I want to develop a desktop program, and one of the most important criteria is having a wonderful user interface - both in terms of usability and style. When I say style, I mean the cool designs (and effects) that one normally associates with Android/Apple applications. I wish to design a user interface, similar (or inspired from) to the one designed for Light Table by Chris Granger. Here's the link to Light Table: http://www.kickstarter.com/projects/ibdknox/light-table
Even Autodesk Maya has been designed using Qt.
Also, I wish to design the interface by drag-n-drop methods, so I finish the interface part quickly and move on to other important parts of the program.
I've worked with Java Swing and AWT. But they provide native interfaces, which are good and easy to use, but doesn't fit the style/cool factor. So I tried Qt. Qt is a major improvement over Swing, I felt. But being new to it, I haven't been able to judge it's full capability. Interfaces of VLC and Maya have been designed with Qt, so I know Qt is the way to go.
Now, Qt provides two major tools for UI design - Qt Designer and Qt Quick.
Their docs and site say that Qt Designer should be used for Desktop applications and that it would give you a native style interface. But I don't want a native style interface. Qt Quick on the other hand, promises to give me exactly what I want (stylish looks etc), but their doc says Qt Quick is to be used for Mobile Application.
Is it possible to use Qt Quick for desktop UI design?
Or, is it possible to extract out of Qt Designer, the kind of design I wish to implement?
I also liked the Autodesk Maya interface design and would like to give my program that kind of touch.
Besides, are there other or better cross-platform tools for UI design. Another reason for me choosing Qt is it is cross-platform. I want my program to run on Linux/Windows/Mac all the same.
After 4 years of absence I'm finally coming back to Qt development again. I'm quite impressed by the development it has gone through, but also a bit confused by Qt Quick, which got just introduced in Qt 4.7
For me it seems like something to build a quick, appealing GUI with some logic in Java Script. However, if I'm going to build a C++ application, is Qt Quick also the modern way of building a GUI for that or should I follow the classic path by using the .ui files?
Qt Quick should fill a much needed gap but whether that means it will become the way to build applications will largely be determined on the type of applications you intend to build.
Qt has provided .ui files for a long time. These files are easy to work with when you need to create applications based on standard widgets. Designer makes it easy to layout the widgets and do other basic operations.
Qt 4.2 introduce style sheets (qss) that made it possible to style existing widgets. These styles are convenient ways of styling the standard widgets to get away from the standard widgets' look-and-feel, while retaining basic functionality.
But sometimes you need to create custom widgets, widgets that don't exist. Before Qt quick, the only way to do this was to write native code (be it C++ or, with language bindings, Python or Ruby). With Qt Quick it's now quite possible to write widgets and full blown UIs that would otherwise be somewhat painful to write in code. Because Qt quick's focus is on the UI, it's becomes a better development language for that goal. The Qt Quick paradigm also transcends the idea of strict standard widgets, adding support for transitions and boundary-less widgets.
The answer really depends on the type of application you're planning to build and I consider the description provided on the page you linked to very accurate:
"Qt Quick helps programmers and designers collaborate to build the fluid user interfaces that are becoming common in portable consumer devices, such as mobile phones, media players, set-top boxes and netbooks."
At the moment, Qt Quick is certainly not the most obvious choice if you're planning on building a classical desktop application, an area of development which the Qt library traditionally excels at, and in this case you're probably better off using what you call "the classic .ui approach"; at the same time, I think that's the exact reason why Qt Quick was introduced: to add a new tool to facilitate the development (or rapid prototyping) of applications not focused on the desktop.