问题

I have to create an app in which the iPhone goes silent upon a button press event.

How can you do this programatically?

回答1:

There is nothing in official iOS SDK to do this. Imagine someone miss an important call because an app changed settings and made phone silent without user's knowledge. I don't want to download that application for sure. See this related question too.

From Apple's documentation

People, not applications, should initiate and control actions. Although an application can suggest a course of action or warn about dangerous consequences, it’s usually a mistake for the app to take decision-making away from the user. The best apps find the correct balance between giving people the capabilities they need while helping them avoid dangerous outcomes.

If I am not mistaken, making phone silent is one these kind of action.

Read the sound section of apple documentation.

EDIT : If you want more information.

Go to apple developer forum (You must have a login), and see this thread. The guy who answers there is an apple employee.

回答2:

// "Ambient" makes it respect the mute switch
// Must call this once to init session
if (!gAudioSessionInited)
{
    AudioSessionInterruptionListener    inInterruptionListener = NULL;
    OSStatus    error;
    if ((error = AudioSessionInitialize (NULL, NULL, inInterruptionListener, NULL)))
    {
        NSLog(@"*** Error *** error in AudioSessionInitialize: %d.", error);
    }
    else
    {
        gAudioSessionInited = YES;
    }
}

SInt32  ambient = kAudioSessionCategory_AmbientSound;
if (AudioSessionSetProperty (kAudioSessionProperty_AudioCategory, sizeof (ambient), &ambient))
{
        NSLog(@"*** Error *** could not set Session property to ambient.");
}

Hope this will help you ...

回答3:

-(BOOL)muteSwitchEnabled {

#if TARGET_IPHONE_SIMULATOR
    // set to NO in simulator. Code causes crashes for some reason.
    return NO;
#endif

// go back to Ambient to detect the switch
AVAudioSession* sharedSession = [AVAudioSession sharedInstance];
[sharedSession setCategory:AVAudioSessionCategoryAmbient error:nil];

CFStringRef state;
UInt32 propertySize = sizeof(CFStringRef);
AudioSessionInitialize(NULL, NULL, NULL, NULL);
AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &state);

BOOL muteSwitch = (CFStringGetLength(state) <= 0);
NSLog(@"Mute switch: %d",muteSwitch);

// code below here is just restoring my own audio state, YMMV
_hasMicrophone = [sharedSession inputIsAvailable];
NSError* setCategoryError = nil;

if (_hasMicrophone) {

    [sharedSession setCategory: AVAudioSessionCategoryPlayAndRecord error: &setCategoryError];

    // By default PlayAndRecord plays out over the internal speaker.  We want the external speakers, thanks.
    UInt32 ASRoute = kAudioSessionOverrideAudioRoute_Speaker;
    AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,
                             sizeof (ASRoute),
                             &ASRoute
                             );
}
else
    // Devices with no mike don't support PlayAndRecord - we don't get playback, so use just playback as we don't have a microphone anyway
    [sharedSession setCategory: AVAudioSessionCategoryPlayback error: &setCategoryError];

if (setCategoryError)
    NSLog(@"Error setting audio category! %@", setCategoryError);

return muteSwitch;
}

first switch to ambient, read the switch, and then return to the settings ...

回答4:

there is no public api is open for the developers because when your app is running and you got a call then your app will quit or may be in background but you cann't make any changes to device .because call is also made on the system level event

来源：https://stackoverflow.com/questions/7306790/programmatically-silence-iphone-from-app

标签

iphone