iOS7及以上版本麦克风权限操作

https://www.jianshu.com/p/8d418aea7221

+ (NSInteger)authorizationStatus
{
    if ( @available(iOS 8,*) ){
        return [[AVAudioSession sharedInstance] recordPermission];
    }
    else if (@available(iOS 7,*))
    {
        bool hasBeenAsked =
        [[NSUserDefaults standardUserDefaults] boolForKey:kHasBeenAskedForMicrophonePermission];
        if (hasBeenAsked) {
            dispatch_semaphore_t sema = dispatch_semaphore_create(0);
            __block BOOL hasAccess;
            [[AVAudioSession sharedInstance] requestRecordPermission:^(BOOL granted) {
                hasAccess = granted;
                dispatch_semaphore_signal(sema);
            }];
            dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
            
            return hasAccess ? 2 : 1;
        } else {
            return 0;
        }
    }
    else
        return 2;
}

+ (void)authorizeWithCompletion:(void(^)(BOOL granted,BOOL firstTime))completion
{
    AVAudioSession *audioSession = [AVAudioSession sharedInstance];

    if (@available(iOS 8.0, *)) {

        AVAudioSessionRecordPermission permission = [audioSession recordPermission];
        switch (permission) {
            case AVAudioSessionRecordPermissionGranted: {
                if (completion) {
                    completion(YES, NO);
                }
            }
                break;
            case AVAudioSessionRecordPermissionDenied: {
                if (completion) {
                    completion(NO, NO);
                }
            }
                break;
            case AVAudioSessionRecordPermissionUndetermined:
            {
                AVAudioSession *session = [[AVAudioSession alloc] init];
                NSError *error;
                [session setCategory:@"AVAudioSessionCategoryPlayAndRecord" error:&error];
                [session requestRecordPermission:^(BOOL granted) {
                    if (completion) {
                        dispatch_async(dispatch_get_main_queue(), ^{
                            completion(granted,YES);
                        });
                    }
                }];
            }
                break;
            default:
            {
                completion(NO,YES);
            }
                break;
        }
    }
    else if([audioSession respondsToSelector:@selector(requestRecordPermission:)])
    {
        [audioSession requestRecordPermission:^(BOOL granted) {
            
            NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];

            if (completion) {
                BOOL hasBeenAskedPermission = [ud boolForKey:kHasBeenAskedForMicrophonePermission];
                dispatch_async(dispatch_get_main_queue(), ^{
                    completion(granted,!hasBeenAskedPermission);
                });
            }
            
            [ud setBool:YES forKey:kHasBeenAskedForMicrophonePermission];
            [ud synchronize];
        }];
    }
    else
    {
        completion(YES, NO);
    }
}