Good reference for editing Qt .ui files? - qt

At times I find myself editing the XML files on Qt creator rather than using the drag and drop interface for example if I can't get my widgets in the correct row of my grid layout. Is there a good reference anywhere on how to lay UIs out using XML? For example, I'd been interested in altering the visibility of a checkbox in the XML rather than in C++ code... is this doable, or am I too much in the WPF mindset? Either way, I'd still be interested in that reference.

You may find the Qt Designer's UI File Format page useful.
I generally just use the designer to prototype something quickly, and then code it up in C++ once the design is correct. Breaking the UI up into custom widgets, rather than one massive form often produces something more manageable.

I've been using Qt for 4 years but I never modified the UI files directly. I always do it using Qt Designer. Not sure why you ever need to modify the XML file directly.
This is not answer to your question, but I believe you're missing how to use Qt Designer. Please check Qt Designer's Manual first.

Related

Can I edit form1.ui.h outside of qt editor?

The Title says everything. I'm pretty new to qt and don't really like the editor it provides.
vim form1.ui.h doesn't work.
Most likely you mean header file generated from your .ui file. Well, since it's generated - editing it is not very good idea, because it will be regenerated from .ui each time you build you program.
But you obviously can:
Edit .ui file with any xml/text editor. Though it's really strange and wouldn't win much over using designer itself.
Do not use .ui files at all - encapsulate creation of desired interfaces in your own classes containing simple C++/Qt code. That way actually is not that bad if you're experienced with Qt layout/widget system and know what you wish to achieve. Because there's no any kind of pixel hunting needs to be done in designer and placing things in appropriate way may actually be done even in more structured manner in code than in form creation. Though as I said it's not the way for everyone and you have to be accurate, also it's better separate interface code from other functionality.

Qt GUI in designer or in code?

When it comes to designing a GUI in Qt, I am hesitating between using the designer in Qt Creator, or doing everything in source code. I'm using Qt widgets and not QML.
If I use the designer I can easily create a GUI using qt standard widgets. But as soon as I need to subclass a widget to extend its functionality I have to build a Designer plugin to support my new widget. Is that correct? Or is there another way to it?
You can build all the GUI in Designer including custom widgets, and you can also build your custom widgets in Designer.
Designer does not need to interpret your custom widgets. Just use the promote functionality. With promote, you start with a plain widget within Designer and then tell the "real" class of it (your custom one) and the header file where it is decleared. The only drawback is that within Designer, it will stay looking like an empty widget.
In my experience, it is much better to use Designer for the GUI than writing source code yourself. You can easily change all the properties afterwards etc., and it is helpful even if you rely on custom widgets. Source code is not a good declarative language for GUI objects, with all the properties etc. Also you cannot play around, you would need to compile all the time just to tell "Is it better to have this text label in bold font?".
Sometimes I edit the XML files that are created by Designer by hand. For example, if I want to put a widget somewhere else in the object tree. If you don't mess up the XML, Designer will still read it and not destroy your changes. The only reason I see for writing GUI in source code is when you have repetitive elements, or dynamic changes based on data input, e.g. a for()-loop that produces elements. In my project I have some Selector Boxes that are filled with options in the source code.
And btw: If you prefer to write your GUI in code instead of using Designer, maybe you are not the right person to craft the GUI. Most programmers don't understand that while they are technically able to design a GUI, they are not always also competent in doing it.
http://hallofshame.gp.co.at/index.php?file=shame.htm&mode=original
It is a bit of a shortcut, but I often use a simple QWidget as a container for my custom widget. This way, I can setup sizing policies, put the whole thing in the layout I want before my custom widget is even in. Then, in C++, I add the custom widget as a child of the container widget.
edit: As ypnos mentioned you can promote the placeholder directly. You can find guidelines here

Using Ui forms:Dynamic Dialogs(runtime) vs adding ui through uic(compile time)

I want to know which way is efficient if I am having number of UI forms. I don have any idea about memory utilization in both of case I just tried both ways in a simple example.
http://qt-project.org/doc/qt-4.8/designer-using-a-ui-file.html here they described both ways.
Now which one method is more efficient?
I want to know which way is efficient if I am having number of UI forms
Take a look at this thread: Hand Coded GUI Versus Qt Designer GUI (Hand Coded GUI Versus Qt Designer GUI)
I don have any idea about memory utilization in both of case
This is the same in both cases. Apart from that you don't need to care of it if your class is derived from QObject.
UI files are just a simpler way to generate more Qt correct layouts. It's also much easier to work with designer than to hand code your UI and designer allows for previewing your changes so no generation and compilation needed in most cases. Also, designer allows you to insert your custom widgets using the "Promote to..." option in the context menu for each widget.
The net result of designer code may look messier but it's exactly the same as you manually laying out and is much less prone to error.

C++ Qt - Hierarchy in the elements added to a GUI

In general, is the order in which I add my widgets into each other, the same order I access them back?
Example:
If I have a bunch of QPushButton in a QHBoxLayout, and this layout in a Window::ui,
can I access those button by simply ui->button_name? or Do I must do ui->layout->itemAt(idx)?
EDIT: My question aims to find an easy way to access elements that are deep into the hierarchy, like a label in a frame, inside a layout, inside a frame, inside the window etc...
PS: Also, I would really appreciate any documentations about good practices of GUI architecture!
Use ui->object_name you don;t need to worry about the layout!
It's possible to redesign the layout, eg. for different platforms, without changing any of the C++ code.
There are a couple of good books on Qt and the sample code is very good.
C++ GUI Programming with Qt 4
Advanced Qt Programming

Qt Designer vs Handcoding

Every time I start a project with some graphical toolkit, one of the first conflicts happen with the decision of how to deal with the visual design and the widget layout: A graphical tool or handcoding?
This is a quite tricky/subjective question because most people will decide based on personal preference. It also depends greatly on the quality of the graphical tool. In this case I would like to focus just on the latest version of the QT library. I do not intend to discuss which method is better. I am convinced that the best answer is: depends on the project.
What I want is a reference to a good non biased article, based on experience after several projects. The article should just describe the tradeoffs of both choices
I started with doing everything hand-coded, and of late have been switching to using Qt Designer for most forms. Here are some benefits for each position:
Using Qt Designer
The biggest time saver for me is managing complex layouts; it saves a lot of tedious coding. Simply (very roughly) arrange your widgets, select them, right-click, and put them in the correct type of layout. Especially as layouts become nested, this is so much easier.
It tends to keep your implementation files cleaner instead of filling them with all the boilerplate layout code. I'm type-A, so I like that.
If you are translating your application, it is possible to send your translators the .ui files so they can see on your GUI where the text they are translating will be. (Assuming they are using Qt Linguist.)
Hand-coding
Control. If you have a layout where you need to instantiate / initialize the controls in a very particular order, or dynamically create the controls based on other criteria (database lookup, etc.), this is the easiest way.
If you have custom widgets, you can kind-of-sort-of use the Designer, adding the closest built-in QWidget from which your class derived and then "upgrading" it. But you won't see a preview of your widget unless you make it a designer plugin in a separate project, which is way too much work for most use cases.
If you have custom widgets that take parameters in their constructor beyond the optional QWidget parent, Designer can't handle it. You have no choice but to add that control manually.
Miscellaneous
I don't use the auto-connect SLOTS and SIGNALS feature (based on naming convention such as "on_my_button_clicked".) I have found that I almost invariably have to set up this connection at a determinate time, not whenever Qt does it for me.
For QWizard forms, I have found that I need to use a different UI file for each page. You can do it all in one, but it becomes very awkward to communicate between pages in any kind of custom way.
In summary, I start with Qt Designer and let it take me as far as it can, then hand-code it from there. That's one nice thing about what Qt Designer generates--it is just another class that becomes a member of your class, and you can access it and manipulate it as you need.
My answer is based on two years developing biochemistry applications using PyQt4 (Python bindings to Qt 4) and OpenGL. I have not done C++ Qt, because we only used C++ for performance-critical algorithms. That said, the PyQt4 API greatly resembles Qt4, so much here still applies.
Qt Designer
Good
Exploration. Discover what widgets are available, the names for those widgets, what properties you can set for each, etc.
Enforces separation of UI logic from application logic.
Bad
If you need to add or remove widgets at run-time, you have to have that logic in code. I think it's a bad idea to put your UI logic in two places.
Making changes to nested layouts. When a layout has no widgets in it, it collapses, and it can be really hard to drag and drop a widget in to the location you want.
Hand coding
Good
Fast if you are very familiar with Qt.
Best choice if you need to add or remove widgets at run-time.
Easier than Qt Designer if you have your own custom widgets.
With discipline, you can still separate UI layout from behavior. Just put your code to create and layout widgets in one place, and your code to set signals and slots in another place.
Bad
Slow if you are new to Qt.
Does not enforce separation of layout from behavior.
Tips
Don't just jump into creating your windows. Start by quickly sketching several possible designs, either on paper or using a tool like Balsamiq Mockups. Though you could do this in Qt Designer, I think it is too tempting to spend a lot of time trying to get your windows to look just right before you've even decided if it is the best design.
If you use Qt Designer for PyQt, you have the extra step of running pyuic4 to compile your *.ui files to Python source files. I found it easy to forget this step and scratch my head for a second why my changes didn't work.
If you code your UI by hand, I suggest putting your layout code in one place and your signals and slots in another place. Doing this makes it easier to change the way your widgets are arranged on a window without affecting any of your application logic. Or you can change some behavior without having to wade through all the layout code.
Enjoy Qt! Now that I am using Java Swing for work, I miss it.
I tend to layout dialogs using the designer but I do all the event handling stuff in the main code. I also do all the main windows, toolbars, menus in direct code.
The designer is just frustrating - a pity since decent drag and drop sizer based designers have been around for more than a decade
It depends on the number of different windows/panels you need for your application. If the number is small, use a graphical tool. It is much faster to get a few windows designed perfectly. If the number is large, the graphical tool can (and should) only be used for prototypes. You need to code the layout to be able to make application-wide changes at acceptable cost.
That includes creating a model of how the UI of the application works and dynamically adding and removing widgets at runtime. For an excellent example of such a model (in a different environment), take a look at the glamour model for creating object browsers.
I object to the suggestion that it is tricky/subjective (at least more than other development choices). It is easy to come up with criteria to decide on. Personal experience and preference are important for that, as they decide when the number of different windows should be considered small. The same goes for tool quality.
My personal opinion (just personal), all GUI based development distracts me too much, my imagination or my mind works very bad when i'm seeing gui objects, i prefer to hand-coding most the time because my imagination works better, you know, is like you were reading a book with no images... when i see nothing else than code its looks like i finish faster...
Second reason, i like c++ so much, so I see the good side of hand-coding, is that I keep my c++ practice no matter if I'm writing something redundant... Coding skill is improved when you only use text... Indeed, i could use nano or vim, but that is too far slow for debuging.
Hand-coding here ++vote
I use a combination of both:
I find for x,y coordinates, Designer is the way to go.
A lot of the other UI properties etc can be set in your code.
I think trying to do UI completely by hand-coding would be a very time consuming project. It's not as simple as setting up HTML tables.
Yes version 4 is bad, but people at work who have used version 3 said it was REALLY bad. Lots of crashing.
I, along with my fellow QTers, are truly hoping that version 5 will be an improvement.
I know this is an old question, but I hope this helps! One man's experience.

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