Re: Problems with ScriptingBridge and iTunes

FROM : Adam P Jenkins
DATE : Mon Mar 03 00:40:54 2008

On Mar 2, 2008, at 6:16 PM, Adam P Jenkins wrote:

> Just call the "get" method on the track object that currentTrack 
> returns to get the iTunesFileTrack object.  I.e. this works
>
> iTunesFileTrack *currentTrack = [[iTunes currentTrack] get];
> NSLog("location is %@", currentTrack.location);
>
> The documentation for the "get" method from the SBObject.h header is:
>
>     // Evaluate the object by sending it to the target application. 
> Depending on what
>     // the object points to, the result may be a Foundation object such 
> as an NSString
>     // (for most properties), an NSAppleEventDescriptor (for properties 
> of a type with
>     // no Foundation equivalent), or another SBObject (for most 
> elements).
>
> Another example of where you need to use it in the iTunes SB 
> interface is when accessing iTunes.selection property, which returns 
> an SBObject, but then if you call "get" on it,  you get an NSCFArray 
> of tracks, which is what you wanted in the first place.  I'm not 
> sure what the logic is behind the "get" method, but there it is.


I just read the detailed and very informative post that "has" just 
posted about AppleScript's event semantics and scripting bridge, and 
now I understand what the "get" method is for and why it needs to be 
called.  This also made me realize that what I posted above isn't 
really safe since currentTrack won't always be a iTunesFileTrack.  So 
really you'd want something like:

iTunesTrack *currentTrack = [iTunes.currentTrack get];
if ([currentTrack isKindOfClass:[iTunesFileTrack class]]) {
  iTunesFileTrack *fileTrack = (iTunesFileTrack*)currentTrack;
  NSLog("location = %@", fileTrack.location);
}