CODEWITHSUNDEEP
c++qtuser-interface
Nickersoft
Nickersoft

Reputation: 684

How do you programatically update the UI in Qt?

I'm fairly new to Qt, and am trying to wrap my head around signals and slots. Though I've figured out how to create custom slots, I've yet to figure out how do update the GUI from my C++ code. I realized that the entire UI, which I created in the designer, is only written in what appears to be XML based UI code. Do I have to handwrite my own Qt C++ UI in order to update the interface, or can I somehow use C++ to update the XML based UI? I'm just looking to add a widget to the main form on a button click. Any help is appreciated. Thanks!

Upvotes: 1

Views: 947

Answers (3)

Zlatomir
Zlatomir

Reputation: 7034

That xml is used by Qt designer and outside of designer it's only used by uic as a source to generate C++ code, so everything that you do in the designer end-up as C++ code, so it can be updated (or done completely) in C++ code (you can look into the code and see that you most likely have a member called ui that is most likely a pointer, but it can also be an instance of a C++ class that is generated for you by uic, and trough that ui member you can access the widgets and layouts that you created in the designer).

A generic resource that i recommend you to read can be found here and then (if you still can't figure it out) ask a specific question about what exactly are you trying to achieve.
LE: that link contains 3 methods to use the generated code into C++ code, don't try all of them into your working project, you may choose one method or use the default one (ui member pointer)

Upvotes: 0

Wagmare
Wagmare

Reputation: 1406

you dont havfe to update the xml of UI . you can inherit the ui into your own class using setupUi http://crpppc19.epfl.ch/doc/qt4-doc-html/html/qwidget.html#setupUi

now in your C++ class you can update the widgets like changing label text, lineEdit text, setting up spinbox value using Signals & slot.

Upvotes: 0

CapelliC
CapelliC

Reputation: 60004

To add a widget to a form you can simply do 

ui->layout()->addWidget(new Widget);

XML is used by QtDesigner as a mean to create, update, and persist your GUI, enabling a visual approach to development, but in the end you can build your application entirely without it.

Upvotes: 1

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