How to change track position on lock screen/control center?

Question

When playing a song with the ios 7 music app the user can use slider to change song position in the lock screen/the control center. Slider is active:

Answer 1

You can change track position with help of MPRemoteCommandCenter on iOS 9.1 and higher.

if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_9_0) {
            MPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];
            [commandCenter.changePlaybackPositionCommand setEnabled:true];
            [commandCenter.changePlaybackPositionCommand addTarget:self action:@selector(changedThumbSliderOnLockScreen:)];
        }

and method

- (MPRemoteCommandHandlerStatus)changedThumbSliderOnLockScreen:(MPChangePlaybackPositionCommandEvent *)event
{
    // change position
    [self setCurrentPlaybackTime:event.positionTime];
    // update MPNowPlayingInfoPropertyElapsedPlaybackTime
    [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo];

    return MPRemoteCommandHandlerStatusSuccess;
}