问题
I have been trying to figure out how to get the iTunes artwork for the currently playing song with scripting bridge. I have gotten to a point where it works for some songs, but for others, I get a SIGABRT. I'm not sure what the issue could be, so any help would be greatly appreciated. Here is what I have so far:
iTunesApplication * iTunes = [SBApplication applicationWithBundleIdentifier:@"com.apple.iTunes"];
NSImage *songArtwork;
iTunesTrack *current = [iTunes currentTrack];
iTunesArtwork *artwork = (iTunesArtwork *)[[[current artworks] get] lastObject];
if(artwork != nil)
songArtwork = [artwork data];
else
songArtwork = [NSImage imageNamed:@"Image.tiff"];
NSMenuItem *artworkMenuItem = [[NSMenuItem alloc] initWithTitle:@"" action:NULL keyEquivalent:@""];
[songArtwork setSize:NSMakeSize(128, 128)];
[artworkMenuItem setImage:songArtwork];
[Menu insertItem:artworkMenuItem atIndex:0];
I for some songs it works, and displays the artwork nicely in the menu item, but for others I get a SIGABRT on the line:
[songArtwork setSize:NSMakeSize(128, 128)];
The output of the console is as follows:
2011-08-12 23:13:20.094 SongViewer[2146:707] -[NSAppleEventDescriptor setSize:]: unrecognized selector sent to instance 0x102827f70
2011-08-12 23:13:20.095 SongViewer[2146:707] An uncaught exception was raised
2011-08-12 23:13:20.096 SongViewer[2146:707] -[NSAppleEventDescriptor setSize:]: unrecognized selector sent to instance 0x102827f70
2011-08-12 23:13:20.097 SongViewer[2146:707] (
0 CoreFoundation 0x00007fff86f11986 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff8b04cd5e objc_exception_throw + 43
2 CoreFoundation 0x00007fff86f9d5ae -[NSObject doesNotRecognizeSelector:] + 190
3 CoreFoundation 0x00007fff86efe803 ___forwarding___ + 371
4 CoreFoundation 0x00007fff86efe618 _CF_forwarding_prep_0 + 232
5 SongViewer 0x0000000100002a83 -[IPMenulet awakeFromNib] + 4483
6 CoreFoundation 0x00007fff86f089e1 -[NSObject performSelector:] + 49
7 CoreFoundation 0x00007fff86f08962 -[NSSet makeObjectsPerformSelector:] + 274
8 AppKit 0x00007fff8d9d9c27 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 1245
9 AppKit 0x00007fff8d9d01b9 loadNib + 322
10 AppKit 0x00007fff8d9cf6b6 +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 217
11 AppKit 0x00007fff8d9cf5d1 +[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:] + 141
12 AppKit 0x00007fff8d9cf514 +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 364
13 AppKit 0x00007fff8dc42355 NSApplicationMain + 398
14 SongViewer 0x0000000100001882 main + 34
15 SongViewer 0x0000000100001854 start + 52
)
2011-08-12 23:13:20.098 SongViewer[2146:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSAppleEventDescriptor setSize:]: unrecognized selector sent to instance 0x102827f70'
*** First throw call stack:
(
0 CoreFoundation 0x00007fff86f11986 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff8b04cd5e objc_exception_throw + 43
2 CoreFoundation 0x00007fff86f9d5ae -[NSObject doesNotRecognizeSelector:] + 190
3 CoreFoundation 0x00007fff86efe803 ___forwarding___ + 371
4 CoreFoundation 0x00007fff86efe618 _CF_forwarding_prep_0 + 232
5 SongViewer 0x0000000100002a83 -[IPMenulet awakeFromNib] + 4483
6 CoreFoundation 0x00007fff86f089e1 -[NSObject performSelector:] + 49
7 CoreFoundation 0x00007fff86f08962 -[NSSet makeObjectsPerformSelector:] + 274
8 AppKit 0x00007fff8d9d9c27 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 1245
9 AppKit 0x00007fff8d9d01b9 loadNib + 322
10 AppKit 0x00007fff8d9cf6b6 +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 217
11 AppKit 0x00007fff8d9cf5d1 +[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:] + 141
12 AppKit 0x00007fff8d9cf514 +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 364
13 AppKit 0x00007fff8dc42355 NSApplicationMain + 398
14 SongViewer 0x0000000100001882 main + 34
15 SongViewer 0x0000000100001854 start + 52
)
terminate called throwing an exception(gdb)
If anyone has any idea what could be wrong, please let me know!!
回答1:
Ok so I figured it out. The solution is to use the NSData raw data provided by the API rather than the NSImage. So I used:
NSImage *songArtwork = [[NSImage alloc] initWithData:[artwork rawData]];
rather than
songArtwork = [artwork data];
回答2:
I have to fetch batch of track artworks from iTunes and use ‘rawData’ too. But this way is inefficient. I found a better way (actually it decreases ‘fetch’ time about 2 times, it’s very significant when fetching artworks for many tracks using ‘valueForKey:’ according to «Improving the Performance of Scripting Bridge Code»).
So I decided to understand what’s wrong with iTunesArtwork ‘data’ property. We expect to get an NSImage object (according to iTunes.h ), but real object is kind of ‘NSAppleEventDescriptor’. And it’s easy to guess, that this object contains an image for us. So we can just use ‘data’ property to get image data. And this is really faster than getting ‘rawData’ from iTunesArtwork. But sometimes iTunes return NSImage object instead NSAppleEventDescriptor. This is an strange behavior, but it's still faster then using rawData.
来源：https://stackoverflow.com/questions/7035350/get-itunes-artwork-for-current-song-with-scriptingbridge