How different is Qt4 from Qt3?

Question

I used to program in Qt3 a long time ago and I had read a great book that I still have by O'reilly on Qt3. I wanted to start using Qt4 again now several years later.

Can I use my Qt3 book to get up to speed again, or has things changed so much that I should buy a Qt4 book?

Answer 1

In a nutshell:

• Qt 4 is (even) better -- and more powerful and flexible -- than Qt 3
• you'll be fine!

The Porting to Qt 4 documentation gives some idea of the many small changes to APIs.

What's New in Qt 4 gives an overview of the big differences between Qt 3 and Qt 4.

Some major changes that noone has mentioned so far:

• Model/View architecture
• template container classes
• a new, modular build system
• a new action-based main window implementation
• widget styling with CSS
• ports for S60 and other platforms

There are also lots of small fixes, improvements and useful new classes such as QFormLayout and QSignalSpy.

Answer 2

You should consult the Qt books page at Nokia.

Two books from that page are available freely:

• C++ GUI Programming with Qt 4 (first edition) by Jasmin Blanchette and Mark Summerfield
• An Introduction to Design Patterns in C++ with Qt 4 by Alan Ezust, Paul Ezust

Answer 3

Qt3 support classes still exist in Qt4 but Qt has developed itself very much. I think using your Qt3 book will slow you down. It is best if you buy a new book.

If you don't want to spend money on a book, examples, tutorials & documentations are very helpful.