这个代码在iOS 4和5中工作,但更新到6后,它不工作(

我发现以下,但不知道如何解决它在代码中.

从iOS 6开始,应用程序需要在其UIBackgroundModes中具有音频密钥才能使用CoreMIDI的MIDISourceCreate和MIDIDestinationCreate函数.没有密钥集,这些功能将返回kMIDINotPermitted(-10844).

2012-09-23 03：40：04.773 MidiStudio [1017：907]错误(创建MIDI虚拟源)：-10844：错误域= NSMachErrorDomain代码= -10844“操作无法完成(Mach error -10844. )”

2012-09-23 03：40：04.777 MidiStudio [1017：907]错误(创建MIDI虚拟目的地)：-10844：错误域= NSMachErrorDomain代码= -10844“操作无法完成(Mach error -10844. )”

这里是’source’的代码：

-(void)setVirtualSourceEnabled:(BOOL)virtualSourceEnabled {
    if ( virtualSourceEnabled == self.virtualSourceEnabled ) return;

    if ( virtualSourceEnabled ) {
        NSString *name = virtualEndpointName ? virtualEndpointName : [[[NSBundle mainBundle] infoDictionary] valueForKey:(NSString*)kcfBundleNameKey];

        OSStatus s = MIDISourceCreate(client,(CFStringRef)name,&virtualSourceEndpoint);
        NSLogError(s,@"Create MIDI virtual source");
        if ( s != noErr ) return;

        virtualSourceDestination = [[PGMidiVirtualSourceDestination alloc] initWithMidi:self endpoint:virtualSourceEndpoint];

        [delegate midi:self destinationAdded:virtualSourceDestination];
        [[NSNotificationCenter defaultCenter] postNotificationName:PGMidiDestinationAddedNotification
                                                            object:self 
                                                          userInfo:[NSDictionary dictionaryWithObject:virtualSourceDestination
                                                                                               forKey:PGMidiEndpointKey]];

    } else {
        [delegate midi:self destinationRemoved:virtualSourceDestination];

        [[NSNotificationCenter defaultCenter] postNotificationName:PGMidiDestinationRemovedNotification
                                                            object:self 
                                                          userInfo:[NSDictionary dictionaryWithObject:virtualSourceDestination
                                                                                               forKey:PGMidiEndpointKey]];

        [virtualSourceDestination release]; virtualSourceDestination = nil;
        OSStatus s = MIDIEndpointDispose(virtualSourceEndpoint);
        NSLogError(s,@"Dispose MIDI virtual source");
        virtualSourceEndpoint = NULL;
    }
}