iOS音频播放 (二)：AudioSession 转

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extern OSStatus AudioSessionInitialize(CFRunLoopRef inRunLoop,
CFStringRef inRunLoopMode,
AudioSessionInterruptionListener inInterruptionListener,
void *inClientData);

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typedef void (*AudioSessionInterruptionListener)(void * inClientData, UInt32 inInterruptionState);

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extern OSStatus AudioSessionAddPropertyListener(AudioSessionPropertyID inID,
AudioSessionPropertyListener inProc,
void *inClientData);

typedef void (*AudioSessionPropertyListener)(void * inClientData,
AudioSessionPropertyID inID,
UInt32 inDataSize,
const void * inData);

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//AudioSession的AudioRouteChangeReason枚举
enum {
kAudioSessionRouteChangeReason_Unknown = 0,
kAudioSessionRouteChangeReason_NewDeviceAvailable = 1,
kAudioSessionRouteChangeReason_OldDeviceUnavailable = 2,
kAudioSessionRouteChangeReason_CategoryChange = 3,
kAudioSessionRouteChangeReason_Override = 4,
kAudioSessionRouteChangeReason_WakeFromSleep = 6,
kAudioSessionRouteChangeReason_NoSuitableRouteForCategory = 7,
kAudioSessionRouteChangeReason_RouteConfigurationChange = 8
};

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//AVAudioSession的AudioRouteChangeReason枚举
typedef NS_ENUM(NSUInteger, AVAudioSessionRouteChangeReason)
{
AVAudioSessionRouteChangeReasonUnknown = 0,
AVAudioSessionRouteChangeReasonNewDeviceAvailable = 1,
AVAudioSessionRouteChangeReasonOldDeviceUnavailable = 2,
AVAudioSessionRouteChangeReasonCategoryChange = 3,
AVAudioSessionRouteChangeReasonOverride = 4,
AVAudioSessionRouteChangeReasonWakeFromSleep = 6,
AVAudioSessionRouteChangeReasonNoSuitableRouteForCategory = 7,
AVAudioSessionRouteChangeReasonRouteConfigurationChange NS_ENUM_AVAILABLE_IOS(7_0) = 8
}

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+ (BOOL)usingHeadset
{
#if TARGET_IPHONE_SIMULATOR
return NO;
#endif

CFStringRef route;
UInt32 propertySize = sizeof(CFStringRef);
AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &route);

BOOL hasHeadset = NO;
if((route == NULL) || (CFStringGetLength(route) == 0))
{
// Silent Mode
}
else
{
/* Known values of route:
* "Headset"
* "Headphone"
* "Speaker"
* "SpeakerAndMicrophone"
* "HeadphonesAndMicrophone"
* "HeadsetInOut"
* "ReceiverAndMicrophone"
* "Lineout"
*/
NSString* routeStr = (__bridge NSString*)route;
NSRange headphoneRange = [routeStr rangeOfString : @"Headphone"];
NSRange headsetRange = [routeStr rangeOfString : @"Headset"];

if (headphoneRange.location != NSNotFound)
{
hasHeadset = YES;
}
else if(headsetRange.location != NSNotFound)
{
hasHeadset = YES;
}
}

if (route)
{
CFRelease(route);
}

return hasHeadset;
}

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+ (BOOL)isAirplayActived
{
CFDictionaryRef currentRouteDescriptionDictionary = nil;
UInt32 dataSize = sizeof(currentRouteDescriptionDictionary);
AudioSessionGetProperty(kAudioSessionProperty_AudioRouteDescription, &dataSize, ¤tRouteDescriptionDictionary);

BOOL airplayActived = NO;
if (currentRouteDescriptionDictionary)
{
CFArrayRef outputs = CFDictionaryGetValue(currentRouteDescriptionDictionary, kAudioSession_AudioRouteKey_Outputs);
if(outputs != NULL && CFArrayGetCount(outputs) > 0)
{
CFDictionaryRef currentOutput = CFArrayGetValueAtIndex(outputs, 0);
//Get the output type (will show airplay / hdmi etc
CFStringRef outputType = CFDictionaryGetValue(currentOutput, kAudioSession_AudioRouteKey_Type);

airplayActived = (CFStringCompare(outputType, kAudioSessionOutputRoute_AirPlay, 0) == kCFCompareEqualTo);
}
CFRelease(currentRouteDescriptionDictionary);
}
return airplayActived;
}

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extern OSStatus AudioSessionSetProperty(AudioSessionPropertyID inID,
UInt32 inDataSize,
const void *inData);

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UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;
AudioSessionSetProperty (kAudioSessionProperty_AudioCategory,
sizeof(sessionCategory),
&sessionCategory);

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/* set session category */
- (BOOL)setCategory:(NSString *)category error:(NSError **)outError;
/* set session category with options */
- (BOOL)setCategory:(NSString *)category withOptions: (AVAudioSessionCategoryOptions)options error:(NSError **)outError NS_AVAILABLE_IOS(6_0);

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//AudioSession的AudioSessionCategory枚举
enum {
kAudioSessionCategory_AmbientSound               = 'ambi',
kAudioSessionCategory_SoloAmbientSound           = 'solo',
kAudioSessionCategory_MediaPlayback              = 'medi',
kAudioSessionCategory_RecordAudio                = 'reca',
kAudioSessionCategory_PlayAndRecord              = 'plar',
kAudioSessionCategory_AudioProcessing            = 'proc'
};

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//AudioSession的AudioSessionCategory字符串
/*  Use this category for background sounds such as rain, car engine noise, etc.
Mixes with other music. */
AVF_EXPORT NSString *const AVAudioSessionCategoryAmbient;

/*  Use this category for background sounds.  Other music will stop playing. */
AVF_EXPORT NSString *const AVAudioSessionCategorySoloAmbient;

/* Use this category for music tracks.*/
AVF_EXPORT NSString *const AVAudioSessionCategoryPlayback;

/*  Use this category when recording audio. */
AVF_EXPORT NSString *const AVAudioSessionCategoryRecord;

/*  Use this category when recording and playing back audio. */
AVF_EXPORT NSString *const AVAudioSessionCategoryPlayAndRecord;

/*  Use this category when using a hardware codec or signal processor while
not playing or recording audio. */
AVF_EXPORT NSString *const AVAudioSessionCategoryAudioProcessing;

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//AudioSession的启动方法
extern OSStatus AudioSessionSetActive(Boolean active);
extern OSStatus AudioSessionSetActiveWithFlags(Boolean active, UInt32 inFlags);

//AVAudioSession的启动方法
- (BOOL)setActive:(BOOL)active error:(NSError **)outError;
- (BOOL)setActive:(BOOL)active withFlags:(NSInteger)flags error:(NSError **)outError NS_DEPRECATED_IOS(4_0, 6_0);
- (BOOL)setActive:(BOOL)active withOptions:(AVAudioSessionSetActiveOptions)options error:(NSError **)outError NS_AVAILABLE_IOS(6_0);

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#import <Endian.h>

NSString * OSStatusToString(OSStatus status)
{
size_t len = sizeof(UInt32);
long addr = (unsigned long)&status;
char cstring[5];

len = (status >> 24) == 0 ? len - 1 : len;
len = (status >> 16) == 0 ? len - 1 : len;
len = (status >>  8) == 0 ? len - 1 : len;
len = (status >>  0) == 0 ?

len - 1 : len;

addr += (4 - len);

status = EndianU32_NtoB(status);        // strings are big endian

strncpy(cstring, (char *)addr, len);
cstring[len] = 0;

return [NSString stringWithCString:(char *)cstring encoding:NSMacOSRomanStringEncoding];
}

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static void MyAudioSessionInterruptionListener(void *inClientData, UInt32 inInterruptionState)
{
AudioSessionInterruptionType interruptionType = kAudioSessionInterruptionType_ShouldNotResume;
UInt32 interruptionTypeSize = sizeof(interruptionType);
AudioSessionGetProperty(kAudioSessionProperty_InterruptionType,
&interruptionTypeSize,
&interruptionType);

NSDictionary *userInfo = @{MyAudioInterruptionStateKey:@(inInterruptionState),
MyAudioInterruptionTypeKey:@(interruptionType)};

[[NSNotificationCenter defaultCenter] postNotificationName:MyAudioInterruptionNotification object:nil userInfo:userInfo];
}

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- (void)interruptionNotificationReceived:(NSNotification *)notification
{
UInt32 interruptionState = [notification.userInfo[MyAudioInterruptionStateKey] unsignedIntValue];
AudioSessionInterruptionType interruptionType = [notification.userInfo[MyAudioInterruptionTypeKey] unsignedIntValue];
[self handleAudioSessionInterruptionWithState:interruptionState type:interruptionType];
}

- (void)handleAudioSessionInterruptionWithState:(UInt32)interruptionState type:(AudioSessionInterruptionType)interruptionType
{
if (interruptionState == kAudioSessionBeginInterruption)
{
//控制UI。暂停播放
}
else if (interruptionState == kAudioSessionEndInterruption)
{
if (interruptionType == kAudioSessionInterruptionType_ShouldResume)
{
OSStatus status = AudioSessionSetActive(true);
if (status == noErr)
{
//控制UI，继续播放
}
}
}
}