[SOLVED] NSSound Delegate implementation

[trev]

Code: Pascal  [Select][+][-]

1. type
2.   NSSound = objcclass external (NSObject)
3.   public  
4.     ...
5.     procedure setDelegate(newValue: NSObject); message 'setDelegate:';
6.     function delegate: NSSoundDelegateProtocol; message 'delegate';    
7.     ...
8.   end;
9.  
10. NSSoundDelegateProtocol = objcprotocol external name 'NSSoundDelegate' (NSObjectProtocol)
11.   optional
12.     procedure sound_didFinishPlaying (sound: NSSound; aBool: ObjCBOOL);
13.        message 'sound:didFinishPlaying:';
14.   end;
15.  
16. NSSoundFinishedDelegate = objcclass(NSObject)
17.   public
18.     procedure didFinishPlaying(Sound: NSSound; FinishedPlaying: Boolean);
19.        message 'sound:didFinishPlaying:';
20.   end;
21.  
22. implementation
23.  
24. var
25.   SoundFinishedDelegate: NSSoundFinishedDelegate;
26.  
27. procedure NSSoundFinishedDelegate.didFinishPlaying(Sound: NSSound; FinishedPlaying: Boolean);
28. begin
29.   if(FinishedPlaying) then
30.      ShowMessage('Sound ' + CFStringToStr(CFStringRef(Sound.Name)) + ' finished');
31. end;                                            
32. ...
33. Initialization
34.   SoundFinishedDelegate := NSSoundFinishedDelegate.alloc.init;
35.   Sound.setDelegate(SoundFinishedDelegate);
36. Finalization
37.   Sound.setDelegate(Nil);
38.   SoundFinishedDelegate.release;
39. end.

Where did I go wrong? All my play/pause/resume procedures work, but my didFinishPlaying procedure never triggers when the sound finishes playing

[skalogryz]

since you're using initialization and finalization sections, I'm assuming you're trying to use them in the console application?

I did a small UI test and it works just fine. (attached). (The path to the sound is hardcoded! you need to change it in the code!)

From the nature of the playing sounds, there's always a problem of synchronization of events. I.e. "end of sounds" can always be reported from a separate thread.
However, the test shows that "end of sounds" is reported to the main thread. That certainly involves having a running event loops.
And such loop typically doesn't exist, if you're writing a console application.

[trev]

Thanks for your working example Dmitry.

Despite 8 errors(!) during the compilation, it succeeds and the application runs without issue...

Compile Project, Target: project1: Success, Errors: 8
Error: <stdin>:1052:10: warning: section "__datacoal_nt" is deprecated
Error: .section __DATA, __datacoal_nt, coalesced
Error: <stdin>:1052:10: note: change section name to "__data"
Error: .section __DATA, __datacoal_nt, coalesced
Error: <stdin>:1092:10: warning: section "__datacoal_nt" is deprecated
Error: .section __DATA, __datacoal_nt, coalesced
Error: <stdin>:1092:10: note: change section name to "__data"
Error: .section __DATA, __datacoal_nt, coalesced

It was in fact a GUI application, not a console application. The initialisation/finalization clauses seemed the way to go, but obviously not! I've now modified it along the lines of your example and... it works!

[skalogryz]

It was in fact a GUI application, not a console application.

here's another thing to try.

In your initial example, class NSSoundFinishedDelegate does implement the method 'sound:didFinishPlaying:', but doesn't implement the protocol. (even though the protocol consists of a single method).

Try your original code, but declare the delegate as implementing the protocol:

Code: Pascal  [Select][+][-]

1. NSSoundFinishedDelegate = objcclass(NSObject, NSSoundDelegateProtocol)
2.   public
3.     procedure sound_didFinishPlaying(Sound: NSSound; FinishedPlaying: Boolean);
4.   end;
5.  

[trev]

That works if I move Sound.setDelegate(SoundFinishedDelegate); from the Initialisation clause to the play procedure.

[skalogryz]

That works if I move Sound.setDelegate(SoundFinishedDelegate); from the Initialisation clause to the play procedure.

when does Sound.initWithXXX occurs? before setting the delegate of after?

[trev]

Code: Pascal  [Select][+][-]

1. procedure TForm1.PlayButtonClick(Sender: TObject);
2. var
3.   audioFilePath: NSString;
4.   status: Boolean;
5. begin
6.   audioFilePath := NSStringUTF8('/Applications/iPhoto.app/Contents/Resources/Music/Barbeque Blues.m4a');
7.   Sound := NSSound.alloc.initWithContentsOfFile_byReference(audioFilePath, True); // File system file
8.  
9.   Sound.setDelegate(SoundFinishedDelegate);
10.  
11.   status := Sound.play;
12.   if(status) then
13.     //
14.   else
15.     ShowMessage('Not OK');
16. end;
17.  

Before ... I just tried after and that doesn't trigger the delegate. Above code works.