AppController.mm
/* |
File: AppController.mm |
Abstract: |
Demonstrates how to enumerate audio devices attached to the system and how to handle device notification. |
This implementation uses the Core Audio Utility Classes and a listener block. |
Version: 2.1.1 |
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*/ |
#import <CoreAudio/CoreAudio.h> |
#import "AppController.h" |
#import "CAHALAudioDevice.h" |
#import "CAHALAudioSystemObject.h" |
#import "CAPropertyAddress.h" |
static void GetAudioDevices(Ptr *devices, UInt32 *devicesAvailable) |
{ |
CAHALAudioSystemObject audioSystemObject; |
*devicesAvailable = audioSystemObject.GetNumberAudioDevices(); |
// make space for the devices we are about to get |
UInt32 theDataSize = *devicesAvailable * sizeof(AudioObjectID); |
if (*devices != NULL) free(*devices); |
*devices = (Ptr)malloc(theDataSize); |
memset(*devices, 0, theDataSize); |
UInt32 ioNumberAudioDevices = *devicesAvailable; |
audioSystemObject.GetAudioDevices(ioNumberAudioDevices, (AudioObjectID *)*devices); |
} |
@implementation AppController |
-(void) awakeFromNib |
{ |
// create empty array to hold device info |
deviceArray = [[NSMutableArray alloc] init]; |
if(!deviceArray) return; |
// generate initial device list |
[self updateDeviceList]; |
// creating the block here allows us access to self so we can call performSelectorOnMainThread when required |
AudioObjectPropertyListenerBlock listenerBlock = ^(UInt32 inNumberAddresses, const AudioObjectPropertyAddress inAddresses[]) { |
for (UInt32 x=0; x<inNumberAddresses; x++) { |
switch (inAddresses[x].mSelector) |
{ |
/* |
* These are the other types of notifications we might receive, however, they are beyond |
* the scope of this sample and we ignore them. |
* |
case kAudioHardwarePropertyDefaultInputDevice: |
fprintf(stderr, "AOPropertyListenerBlock: default input device changed\n"); |
break; |
case kAudioHardwarePropertyDefaultOutputDevice: |
fprintf(stderr, "AOPropertyListenerBlock: default output device changed\n"); |
break; |
case kAudioHardwarePropertyDefaultSystemOutputDevice: |
fprintf(stderr, "AOPropertyListenerBlock: default system output device changed\n"); |
break; |
*/ |
case kAudioHardwarePropertyDevices: |
{ |
fprintf(stderr, "AOPropertyListenerBlock: kAudioHardwarePropertyDevices\n"); |
[self performSelectorOnMainThread:@selector(updateDeviceList) withObject:nil waitUntilDone:NO]; |
} |
break; |
default: |
fprintf(stderr, "AOPropertyListenerBlock: unknown message\n"); |
break; |
} |
} |
}; |
// need to retain the listener block so that we can remove it later |
AOPropertyListenerBlock = Block_copy(listenerBlock); |
// install kAudioHardwarePropertyDevices listener block on the system object |
CAHALAudioSystemObject audioSystemObject; |
audioSystemObject.AddPropertyListenerBlock(CAPropertyAddress(kAudioHardwarePropertyDevices), dispatch_get_main_queue(), AOPropertyListenerBlock); |
} |
- (void)windowWillClose:(NSNotification *)notification |
{ |
// remove kAudioHardwarePropertyDevices listener block |
CAHALAudioSystemObject audioSystemObject; |
audioSystemObject.RemovePropertyListenerBlock(CAPropertyAddress(kAudioHardwarePropertyDevices), dispatch_get_main_queue(), AOPropertyListenerBlock); |
// release the copied block |
Block_release(AOPropertyListenerBlock); |
AOPropertyListenerBlock = NULL; |
} |
- (void)updateDeviceList |
{ |
UInt32 devicesAvailable = 0; |
UInt32 theNumberInputChannels = 0; |
UInt32 theNumberOutputChannels = 0; |
CFNumberRef tempNumberRef = NULL; |
CFStringRef tempStringRef = NULL; |
// clear out any current entries in device array |
[deviceArray removeAllObjects]; |
// fetch a pointer to the list of available devices |
GetAudioDevices((Ptr *)&devices, &devicesAvailable); |
// iterate over each device gathering information |
for (UInt32 loopCount = 0; loopCount < devicesAvailable; loopCount++) { |
// get the object id |
AudioObjectID deviceID = devices[loopCount]; |
// create dictionary to hold device info |
CFMutableDictionaryRef theDict = NULL; |
theDict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); |
if ( theDict == NULL ) { |
fprintf(stderr, "Dictionary Creation Failed\n" ); |
return; |
} |
// save id |
tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type,&deviceID); |
if (tempNumberRef) { |
CFDictionarySetValue(theDict, CFSTR("id"), tempNumberRef); |
CFRelease(tempNumberRef); |
} |
// get current device |
CAHALAudioDevice currentDevice = CAHALAudioDevice::CAHALAudioDevice(deviceID); |
// get device name |
tempStringRef = currentDevice.CopyName(); |
if(tempStringRef) { |
CFDictionarySetValue(theDict, CFSTR("name"), tempStringRef); |
CFRelease(tempStringRef); |
} |
// get number of input channels |
theNumberInputChannels = currentDevice.GetTotalNumberChannels(true); // isInput = true |
tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type,&theNumberInputChannels); |
if (tempNumberRef) { |
CFDictionarySetValue(theDict, CFSTR("ich"), tempNumberRef); |
CFRelease(tempNumberRef); |
} |
// get number of output channels |
theNumberOutputChannels = currentDevice.GetTotalNumberChannels(false); // isInput = false |
tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type,&theNumberOutputChannels); |
if (tempNumberRef) { |
CFDictionarySetValue(theDict, CFSTR("och"), tempNumberRef); |
CFRelease(tempNumberRef); |
} |
[deviceArray addObject:(NSDictionary*)theDict]; |
CFRelease(theDict); |
} |
[myTable reloadData]; |
} |
- (NSUInteger)numberOfRowsInTableView:(NSTableView *)aTableView |
{ |
return [deviceArray count]; |
} |
- (id)tableView:(NSTableView *)aTableView |
objectValueForTableColumn:(NSTableColumn *)aTableColumn |
row:(int)rowIndex |
{ |
NSDictionary *deviceDict = NULL; |
deviceDict = [deviceArray objectAtIndex:rowIndex]; |
return [deviceDict objectForKey:[aTableColumn identifier]]; |
} |
@end |
Copyright © 2012 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2012-11-29