Show a waiting spinner, when loading a signal

[Biehrer]

To indicate that the application is loading a big file from disk(and can't do anything other in the meantime), show a spinner widget on the screen

=>How-to:

1. Load a gif or Qt "movie":

Pseudocode:
QLabel *lbl = new QLabel;
QMovie *movie = new QMovie("G:/loader.gif");
lbl->setMovie(movie);
lbl->show();
movie->start();

Limitation: not resizeable

2. Use widgets which are free on github like:

https://github.com/snowwlex/QtWaitingSpinner
or
https://github.com/mojocorp/QProgressIndicator