Promoting widget don't create the header
I'm trying promoting widgets and use it in another class, when I try to use mywidget it gives me the error "could not fine mywidget.h". The problem is mywidget.h actually does not exists in my laptop... what I'm missing?
It goes the other way around I guess.
You are designing a wigdet derived from Qt class (e.g. QFrame or any other). This creates the implementation and declaration files (in your case mywidget.h). Than your can place a more generic Qt class into your design (e.g. QFrame). This may be promoted to your mywidget.
You don't understand, the problem is the file "mywidget.h" is not created and no exists in my machine when I promote the widget.
@Daguerreo You're a bit vague as to what you're trying to do. What is 'mywidget' and what do you mean by 'promoting'?
The only thing I'm aware of where you can 'promote', is in qdesigner. That again would imply that 'mywidget' is some widget you designed for use inside qdesigner, which then implies you would have implemented the interface described on http://doc.qt.io/qt-5/qdesignercustomwidgetinterface.html. Did you maybe forget to implement the 'includeFile' method?