PayPal acquires award-winning and innovative engineering team of Duff Research

Today we’re happy and excited to announce that Duff Research has joined the PayPal team!

1 year ago
Duff localization expertise quoted in FierceDeveloper article

Over the years we’ve localized multiple apps in many languages and have hard-won experience in how to do it the right way. A few of our insights are quoted in this recent article from FierceDeveloper.

FierceDeveloper:  Does your app work in Portuguese or Chinese?

1 year ago
Dealing with Duplicate Certificates

Sometimes I see the following build error : Certificate identity ‘iPhone Distribution: xxx’ appears more than once in the keychain. The codesign tool requires there only be one

Now whenever I see this, I know that I go into the keychain because there really is a duplicate certificate in there - but I didn’t see one at all - I revoked the cert and provisioning profiles, rebooted my mac, and reinstalled everything and same error… but I finally found a mention of this on the net - if you go to the keychain tool and say View->Show Expired Certificates, there *are* a ton of old expired certs in there that will conflict w/ any new certs you are trying to install - I’ve never seen those before - removing those made everything work…

There’s also a related bug where sometimes the duplicate cert isn’t actually deleted, but the Keychain app removes it from the listed certs anyway. You have to refresh the lists by toggling from the login keychain to the system keychain and back to get it to show up. Then try to delete again, and rinse and repeat until the cert is actually deleted and stops showing up anywhere.

1 year ago
OS X Lion and QuickTime video capture

Starting with OSX Lion, the QuickTime player has the ability to capture to video a portion of your desktop.  Just run your application in the simulator of your choice, Android, iOS, etc and capture the video.

1 year ago
New website

Our new web site is on line!  Check it out at

2 years ago
How to handle "Error : icon file must be greater than 0x0 pixels"

if you are seeing this error when submitting to the ios app store, chances are you are on 10.7.3 Lion — many say the fix is to either:
1) install a new application loader
2) uncheck the compress pngs flag in your project

I wouldn’t recommend either - what works is to change your icon.png files to file type “Icon”… absolutely don’t uncompress your pngs.

2 years ago
Symbolication Tip

so I was just running into all sorts of issues w/ symbolicate not symbolicating… my solution (which I have used in the past) was to call:


this worked like a champ in case anybody is wrestling w/ the same problem…

2 years ago
MonoMac tip for iOS Devs

I just wasted hours trying to load a view from a nib file using MonoMac.   Hopefully this will save you some time.

This is something I do all the time on iOS, so I tried to do

NSArray views = NSBundle.MainBundle.LoadNib(@”MyNib”,this,null);

but it was crashing with an unrecognized selector.   

Turns out that what I needed to do was 

bool loaded = NSBundle.LoadNib(@”MyNib”,this);

On the Mac, Mono’s LoadNib (which maps to loadNibNamed) returns a bool whether the nib was loaded or not, while on iOS loadNibNamed returns an array of views.

2 years ago
Mac programming tip for iOS devs

for a UIView, it is easy to set the borderWidth, cornerRadius, etc by doing the following:

myView.layer.cornerRadius = 8.0;

myView.layer.borderWidth = 2.0;

// etc

I tried this on a Mac app, and it didn’t work.   Hmmm.   Turns out there is one extra line of code required to make this work on a Mac app:

myView.wantsLayer = YES;

2 years ago
Rocknor climbs the charts

As an experiment, we made Rocknor’s Donut Factory free, and within 24 hours it zoomed up the charts around world, reaching #1 in puzzle/strategy in some countries, and top 25 in puzzle/strategy games in almost every store in the world!   It also was one of the top grossing apps in many countries as well thanks to in-app purchase.

Whenever an app goes from paid to free, it triggers all sorts of blogs around the internet, and RDF was fortunate enough to be featured on the front page of many of the prominent one and getting some rave reviews.

If you have an app idea with in-app purchase, you may want to consider selling it for 99 cents for a month or two, then making it free and hoping you can ride a free publicity wave.

2 years ago