How does the "PREVIEW" option in Qt Designer work?

[Charvi]

Thanks for your efforts but I think you are misled.

Whether its 2006 or 2012, I believe writing code for a custom slots is not supported in Qt Designer. Well here are some latest posts which may not be objectionable:

1) http://stackoverflow.com/questions/7...de-to-a-button
2) http://stackoverflow.com/questions/4...qt-designer-go

etcetera.

QUiLoader may be working in the following manner:

A) The Signal/ Slots connections made using the predefined signals and slots in the Designer are between the tags <signal></signal> and <slot></slot> within the <connection></connection> tag int he .ui file.
B) Next while loading the .ui file first the QUiLoader will parse the tags and look for the code of the signals and slots (with name in between the tags) in the Qt Library. It will fetch the code from from there and display the UI.

This way when the particular signal is emitted the code of the slot will be executed. So if I need to implement my custom signals and slots I have to write the corresponding class files (.cpp and .h) which will contain its code.