Apps in OS X that can open files to launch their respective applications often let the user choose the app that'll open the file. An example is the Finder.
I am still unclear about what's the best solution to implement this. The challenges are performance and showing the app's icon.
First, to get the list of apps, I found only LSCopyApplicationURLsForURL().
The major difficulty for me now is to get the app icons. All I have is the URLs (paths) to the apps. The only way I know of to get the icons would be to create a CFBundle object and then read the app's plist to get the icon data. But that appears to invole lots of disk access, and I could imagine it'll be quite inefficient if the app is located on a remote file server.
I believe that there's also a cached database about the apps, which includes icons and display names (without extension), and such. But where is the API for that?
Note: The app is Carbon based, but I can make use of Cocoa (NS...) functions if necessary. Also, Support for 10.5, even 10.4, would be appreciated.
Alright. I solved it eventually.
I now use the Carbon function GetIconRefFromFileInfo(), which still works in Lion, though it's marked deprecated/obsolete.
I had also tried to use QLThumbnailImageCreate(), but that didn't get me any results, oddly. No idea what I did wrong.
For Cocoa apps, [[NSWorkspace sharedWorkspace] iconForFile:path] can be used (thanks to C. Grunenberg of DevonTechnologies for this tip, where it's used with EasyFind).