Qt4.5 vs Cocoa for native Mac UI

Question

I've been developing for Windows and *nix platforms for quite some time, and am looking to move into Mac development. I am tossing up between using ObjC/Cocoa and C++/Qt4.5.

The C++/moc semantics make more sense to me, and improving knowledge in Qt seems like a sensible thing to do given that you end up with a skill set that covers more platforms.

Am I likely to handicap my applications by skipping Cocoa?

The sample Qt applications look pretty Mac-native to me, but they are quite simple so potentially don't tell the whole story. Are there other pros to the Xcode way that Qt doesn't have, such as packaging, deployment, etc.?

Answer 1

Here's an easy way to answer it:

If you were developing a Windows app with .NET or MFC, would you handicap your applications by using Qt? If the answer to that is yes, then the situation is likely to be the same on the Mac.

A few negatives I can think of off the top of my head:

• Licensing
• Qt apps, while good, are not completely a native UI experience and there's things a native UI designer can do in Cocoa which boggle the mind. While I can't be sure that all the same functionality isn't available in Qt, I doubt it.
• Qt is always a little behind. If Microsoft or Apple come out with a great new technology, you have to wait for the Qt developers to update Qt.

However, with all that said, only you can determine the business value of using Qt. If you think cross-platform development is going to be a major part of your development, then Qt might be worth it, despite the issues mentioned.

Answer 2

Ask yourself: how many of the best Mac applications that you know of use Qt instead of native Cocoa?

For our robotic systems, we originally wrote our control software in C++ using the cross-platform wxWidgets library (we avoided Qt due to some licensing concerns), because we felt that we had to target Windows, Linux, and Mac platforms for our end users. This is what we shipped for over a year until I started tinkering with Cocoa.

Right away, the thing that most impressed me was how quickly you could develop using Cocoa. Eventually, we decided to drop support for Linux and Windows and rewrite our entire control applications in Cocoa. What had taken us years to put together in C++ required only three months to completely reimplement in Cocoa.

Aside from the "lowest common denominator" interface issues that others have pointed out, the rapid development allowed by Cocoa has become a competitive advantage for our company. Our software has advanced far more quickly since our conversion to Cocoa, and it has allowed us as a new company with one developer to pull even with 10-year-old competitors that have 20-man development teams. This appears to be a common story in the Mac development space, where you see a lot of small teams who are able to create products that compete with those of much larger companies.

As a final note, using Cocoa gives you the ability to stay on top of the new APIs Apple is continually rolling out. We're now working on a new control interface that will make heavy use of Core Animation, something that would be painful to deal with using Qt.