打開揚(yáng)聲器：

[[AVAudioSession sharedInstance] overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil];

關(guān)閉揚(yáng)聲器：

[[AVAudioSession sharedInstance] overrideOutputAudioPort:AVAudioSessionPortOverrideNone error:nil];

注意：

1:iPad不需要打開關(guān)閉揚(yáng)聲器：因?yàn)閕Pad只有揚(yáng)聲器

2:在打開和關(guān)閉養(yǎng)生起的時(shí)候，需要對(duì)耳機(jī)做處理，如果當(dāng)前處于耳機(jī)插入的時(shí)候，打開揚(yáng)聲器是沒(méi)有作用的。所以需要監(jiān)聽當(dāng)前音頻軌道變化。
//添加耳機(jī)拔掉偵聽事件

AudioSessionInitialize(NULL, NULL, NULL, NULL);

       AudioSessionAddPropertyListener(kAudioSessionProperty_AudioRouteChange,        audioRouteChangeCallback, (__bridge void *)(self));

//耳機(jī)拔掉偵聽事件回調(diào) [AudioManager 為當(dāng)前類，即為self]

 void audioRouteChangeCallback(void*inClientData,AudioSessionPropertyIDinID, UInt32inDataSize,constvoid*inData)
{
    CFDictionaryRefrouteChangeDictionary = inData;
    CFNumberRefrouteChangeReasonRef =CFDictionaryGetValue(routeChangeDictionary,CFSTR(kAudioSession_AudioRouteChangeKey_Reason));
    SInt32routeChangeReason;
CFNumberGetValue(routeChangeReasonRef,kCFNumberSInt32Type, &routeChangeReason);
    AudioManager*_self = (__bridgeAudioManager*)inClientData;
    if (routeChangeReason == kAudioSessionRouteChangeReason_OldDeviceUnavailable) {    //拔掉耳機(jī)
        [_self setSpeakerOn];
    }else if (routeChangeReason ==kAudioSessionRouteChangeReason_NewDeviceAvailable) {    //插入耳機(jī)
    }
}

//檢測(cè)當(dāng)前是否有耳機(jī)：

- (BOOL)hasHeadset
{
    CFStringRef route;
    UInt32propertySize =sizeof(CFStringRef);
    AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &route);
    if((route ==NULL) || (CFStringGetLength(route) ==0))
    {
        // Silent Mode
    }
    else
    {
        NSString* routeStr = (__bridge_transferNSString*)route;
        NSRangeheadphoneRange = [routeStrrangeOfString:@"Headphone"];
        NSRangeheadsetRange = [routeStrrangeOfString:@"Headset"];
        if(headphoneRange.location!=NSNotFound)
        {
            returnYES;
        }elseif(headsetRange.location!=NSNotFound)
        {
            returnYES;
        }
    }
    return NO;
}