how to set an icon on a Main window and action with QT

Question

Honestly I do not understand resource files and how to get so that my things can get done, because it was partially explained to me and I'm quite confused where to put icon and how to make it visible on my programs.

setWindowIcon(QIcon(":/images/icon.png")); 

It doesn't show up or even show a error.

Answer 1

Create a resources file named resources.qrc:

<!DOCTYPE RCC>
<RCC version="1.0">
  <qresource>
    <file>path/to/icon.png</file>
  </qresource>
</RCC>

Make sure that path/to/icon.png is an actual path, relative to the directory that contains resources.qrc.

In your .pro file, include the resource:

TARGET = your_app
TEMPLATE = app
QT += widgets 
RESOURCES += path/to/resources.qrc

Again, make sure that path/to/resources.qrc exists, relative to the directory that contains the project file.

After compiling, your resource will be embedded into your executable. It can be accessed like:

setWindowIcon(QIcon(":/path/to/icon.png"));

If the icon is not appearing, try this stackoverflow question or this one.

Another approach would be to use the Application Icon. This will set the application icon for your application on the desktop and start menus, and also on the top left corner of QMainWindows and QDialogs

Answer 2

Wouldn't it be the simplest to use QtCreator's Designer window? In the lower right corner you can find 3 tabs - click on the most righthand one, then click on the pen:

This will open Resources editor:

Define new resources file (below the left pane), than add a "namespace" (rigth pane) and add your files. You can set aliases for them, so that when you decide to replace your icon with somethin else - you only have to switch the path, as long as alias is kept the same. You can then reference your resources via their alias to set your icon where needed, eg: setWindowIcon(QIcon(":/HurBudClientGUI/plug"));

Also - take your time to read this: http://doc.qt.io/qt-5/resources.html and that: http://doc.qt.io/qt-5/designer-resources.html

Good luck!