Get current iPhone/iPad ringer switch (mute switch) state and change events

RingerSwitchObserver.h

@import Foundation;

NS_ASSUME_NONNULL_BEGIN

FOUNDATION_EXTERN NSString * const RingerSwitchDidChangedNotification;

@interface RingerSwitchObserver : NSObject

@property (nonatomic, readonly, getter=isSlient) BOOL silent;

+ (instancetype)sharedObserver;

@end

NS_ASSUME_NONNULL_END

RingerSwitchObserver.m

#import "RingerSwitchObserver.h"

#import <notify.h>

NS_ASSUME_NONNULL_BEGIN

NSString * const RingerSwitchDidChangedNotification = @"RingerSwitchDidChangedNotification";

@interface RingerSwitchObserver ()

@property (nonatomic, getter=isSlient) BOOL silent;

@end

@implementation RingerSwitchObserver

+ (instancetype)sharedObserver
{
    static dispatch_once_t onceToken;
    static RingerSwitchObserver *sObserver;
    dispatch_once(&onceToken, ^{
        sObserver = [[RingerSwitchObserver alloc] init];
    });
    return sObserver;
}

- (instancetype)init
{
    if (self = [super init]) {
        int token;
        if (notify_register_dispatch("com.apple.springboard.ringerstate", &token, dispatch_get_main_queue(), ^(int token) {
            [self _updateSilentWithToken:token];
        }) == NOTIFY_STATUS_OK) {
            [self _updateSilentWithToken:token];
        } else {
            // Default to assume the ringer switch is ON.
            _silent = YES;
        }
    }
    return self;
}

- (void)_updateSilentWithToken:(int)token
{
    uint64_t state;
    if (notify_get_state(token, &state) == NOTIFY_STATUS_OK) {
        self.silent = (state == 0);
    } else {
        // Default to assume the ringer switch is ON.
        self.silent = YES;
    }
}

- (void)setSilent:(BOOL)silent
{
    if (_silent == silent) {
        return;
    }
    _silent = silent;

    [[NSNotificationCenter defaultCenter] postNotificationName:RingerSwitchDidChangedNotification object:self];
}

@end

NS_ASSUME_NONNULL_END