Qt Widgets and more…

GridLayout in Qt Designer

Welcome to our brand new video series about...Qt Widgets! Yes, widgets are still alive and kicking. In the many years we have worked with them, we have gathered quite a number of tips and tricks that we'd love to share with you.

Whether it's some handy snippet in C++ or a hidden button in a graphical tool, these suggestions will make your development life considerably easier.
In this first video, we will show you a few ways to improve your workflow when using a QGridLayout inside Qt Designer. Sounds simple, doesn't it? Well, there are a few subtleties involved.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

70 17

Populating a Combobox from Qt Designer

Let's revisit Qt Designer once more, this time to discuss combo boxes. Mapping a QComboBox's entry to a specific value is easy in C++, but not so easy when the combo box is populated from within Qt Designer. How do we improve the situation?

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

20 10

Sessions in Qt Creator

This video is private.

20 6

Using Clang-Format to Ensure Style Guidelines

If you're submitting code for a review, there's nothing worse than getting nitpicked because you violated some style guideline of the project.
If you're doing a code review, there's nothing more annoying than nitpicking on small code style inconsistencies.

This is where clang-format can help us. clang-format is a tool (based on the clang/LLVM compiler infrastructure) that can automatically reformat our source code. Not only we can run it manually to apply a given formatting, but we can set it up so that it automatically reformats the code when committing into git, or when saving in Qt Creator.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

40 3

Un-sorting headers in QTableView

Today's video falls in the proverbial "removing the pebble in one's shoes" category. We'll talk about headers in a QTableView. Were you ever slightly annoyed by the fact that you can click on a header and sort the table by the corresponding column, but then you cannot undo the sorting? Let's fix that!

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

17 1

Using GammaRay to Find the Class of an UI Element

Remember this tip: when an application is being introspected by GammaRay, you can use Control + Shift + Mouse click on any of its widgets to select it for further inspection. This lets you check all the properties for the widget, its positioning, as well as simply get an answer to the question: of which class is this widget?

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

5 2

Understanding Contents Margins in Qt Layouts

We know that we should use layouts to arrange chidren widgets inside a container widget. Layouts do the right thing for us automatically. Except when... they don't! Sometimes we need to fine tune some of the decisions that layouts take; usually, the one that they take wrong is deciding how much padding/margins should be applied to contents. Let's see how to fix it.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

14 0

Starting the application from GammaRay

You've seen me constantly use GammaRay, when checking: item sizes, visibility, and layout margins. In this video, let me share with you a little trick: You can launch GammaRay right from within Qt Creator, with a convenient keyboard shortcut.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

Link to the GammaRay Tutorials: https://www.youtube.com/playlist?list=PL6CJYn40gN6itybeSJb5FvRWOxVW5PCUX

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

9 2

Spell checking in Qt Creator

This video is private.

13 2

Communicating between a View/Delegate and a Model

Sometimes a view would like to have more data for a cell than what is in a cell, examples includes:

A view that offer special context menu entries if the cell contains an employee. The text in the cell itself might just be the employees name, and from that alone it would be very hard to come to the conclusion that this the cell indeed holds an employee.

A delegate which shows an annotation symbol (think cut of corner like in excel) if the data behind the cell is annotated. Again the cell text do not reveal this information.

One way to implement this is for the view or delegate to reach out to the model in question using a regular function call, but that will break in case there are proxy models in between.

This video shows how to obtain the effect by using custom roles.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

You can contact us regarding our services at info@kdab.com

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:

KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

29 17

Visualizing the Model Stack in GammaRay

Got a stack of proxy models where there is a subtle bug somewhere in there? No worries --GammaRay to the rescue!

It can visualize the stack of models for you, but there is one thing you better remember in your code --watch this video to find out what it is! 🙂

Link to download GammaRay: https://www.kdab.com/development-resources/qt-tools/gammaray/

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

6 0

Traversing Proxy Models to Get to the Source Model at the Bottom

Sometimes a view or delegate need to ask the model providing the data (at the bottom of a proxy model stack) some questions.

In the previous video 'Communicating between a View/Delegate and a Model': https://youtu.be/q6eOEz_UfTI I showed how custom roles can be used for this.

However, if the data isn't related to a specific cell, a better approach might be to traverse the proxy models yourself, to get to the actual source model.
This video shows this approach.

Link to download KDReports: https://www.kdab.com/development-resources/qt-tools/kd-reports/

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

8 0

Changing the Font to Jetbrains Mono in Qt Creator

This video is private.

9 5

Using Custom Types with Model/View

In this episode I'll show how you can use your own custom types to communicate between a model and a delegate editing these custom types. My example is a Money class which contains a currency and an amount, the delegate will see Money instances, rather than parse them from their string representation.

NOTE: This video was filmed before Qt6 was out and it seems that contrary to rumors the function registerConverter is still there: https://doc.qt.io/qt-6/qmetatype.html#registerConverter

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv .

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

21 0

Top 7 Shortcuts in Qt Creator

As a developer your toolbox should help you as much as possible, and you ought to invest the time it takes to figure out what is in there. This episodes gives you my top seven shortcuts in Qt Creator that helps me save hours (OK, maybe just minutes) every single day, but much more important ensures I stay focused on whatever problem I'm solving right now.

Download our Qt Creator Reference Card that lists lots more useful shortcuts here: https://www.kdab.com/development-resources/qtcreator/

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

35 7

Avoiding QVariant::fromValue around your Own Types

In my code I have a lot of custom classes I use with model/view, including Money, PercentageValue, TimeValue just to name a few.

For years I've written code like this in my data methods of QAbstractItemModel subclasses:
return QVariant::fromValue(cost); // cost is an instance of the class Money
In this short video you will learn a very simple trick to avoid this.

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

22 6

Document Templates in Qt Creator - Part 1

It is possible to have your own document templates in Qt Creator, learn in these four videos how to set that up.

In this first episode, I will create a simple template for new classes based on the "C++ class" template. Further, I'll explain how to use macros, and show the one expanding into the class name specified in the "new file" dialog.

Link to Qt Documentation: https://doc.qt.io/qtcreator/creator-project-wizards.html

The resulting template for these four episodes is in github. You can download it here https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:
KDAB offers experienced software experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

17 2

Document Templates in Qt Creator - Part 2

It is possible to have your own document templates in Qt Creator, learn in these four videos how to set that up.
In this episode I'll show you how to add a new file (namely a .ui file) to the set of files generated, which among other things will teach us a bit more about how the macro system works.

The resulting template for these four episodes is in github. You can download it here https://github.com/KDAB/kdabtv

The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

About KDAB:

KDAB offers experienced software experts to help you deliver functional, high-performing and innovative softwae experts to help you deliver functional, high-performing and innovative software across embedded, mobile and desktop platforms for projects using C++, Qt, QML/Qt Quick, OpenGL, Qt 3D and more. https://www.kdab.com/software-services

KDAB experts regularly take time out to deliver KDAB’s world class training, in-house or at open enrollment courses around the world. We are the market leaders for training in Qt, OpenGL and C++.

Contact us to find out more at training@kdab.com or visit our website: https://www.kdab.com/software-services/scheduled-training/

We are about 90 people, located all around the world. Our Head Office is in Sweden and we have other offices in Germany, France, the UK and the USA. https://www.kdab.com/about/contact/

7 4

Document Templates in Qt Creator - Part 3

This video is private.

6 0

Document Templates in Qt Creator - Part 4

This video is private.

2 0