Is there a public way to force MPNowPlayingInfoCen

Question

I would like Control Center (via MPNowPlayingInfoCenter) to show the forward 15 seconds / back 15 seconds controls that Apple shows with podcasts, like so:

The utter lack of documentation tells me that there's no obvious way to do this, but has anyone out there found any non-obvious way to force this without resorting to a private method?

I've already got my handling for the forward/back button set up to advance appropriately, I'd just like to use the more appropriate UI. Any help would be greatly appreciated.

Answer 1

Oooooooh. Marco Arment got this to work in Overcast, and at least left a breadcrumb trail for the Castro guys with this tweet:

It’s MPRemoteCommandCenter. Good luck with the documentation, though.

Here's said documentation for anyone who's been following this question - I'm guessing it has to do with skipBackwardCommand and skipForwardCommand. I don't have time to look into it this very second, so I'll leave this here in case anyone wants to poke at it and give a more thorough answer.

Answer 2

OK so I had a bit of time on my hands and so I followed the breadcrumb.… This is what I found.

Include the MediaPlayer framework and get hold of the RemoteCommandCenter:

MPRemoteCommandCenter *rcc = [MPRemoteCommandCenter sharedCommandCenter];

then if you wanted to set the skip controls as per Overcast you can do the following:

MPSkipIntervalCommand *skipBackwardIntervalCommand = [rcc skipBackwardCommand];
[skipBackwardIntervalCommand setEnabled:YES];
[skipBackwardIntervalCommand addTarget:self action:@selector(skipBackwardEvent:)];
skipBackwardIntervalCommand.preferredIntervals = @[@(42)];  // Set your own interval

MPSkipIntervalCommand *skipForwardIntervalCommand = [rcc skipForwardCommand];
skipForwardIntervalCommand.preferredIntervals = @[@(42)];  // Max 99
[skipForwardIntervalCommand setEnabled:YES];
[skipForwardIntervalCommand addTarget:self action:@selector(skipForwardEvent:)];

and in the event handlers do what you need to do to skip by the interval:

-(void)skipBackwardEvent: (MPSkipIntervalCommandEvent *)skipEvent
{
    NSLog(@"Skip backward by %f", skipEvent.interval);
}

-(void)skipForwardEvent: (MPSkipIntervalCommandEvent *)skipEvent
{
    NSLog(@"Skip forward by %f", skipEvent.interval);
}

Note: The preferredIntervals property is an NSArray but I haven’t figured out how extra intervals can be utilised by the command center unless you do something with this yourself.

Things to note that I’ve found so far. When you do this you are taking control of all the controls so the default play and pause buttons won't show unless you do the same for them:

MPRemoteCommand *pauseCommand = [rcc pauseCommand];
[pauseCommand setEnabled:YES];
[pauseCommand addTarget:self action:@selector(playOrPauseEvent:)];
//    
MPRemoteCommand *playCommand = [rcc playCommand];
[playCommand setEnabled:YES];
[playCommand addTarget:self action:@selector(playOrPauseEvent:)];

(there is also a togglePlayPauseCommand defined but I could’t get this to fire from the Command Centre - it does fire from headphones though.)

Other discoveries: The buttons are in fixed positions left / middle / right so you cant have (for example) a previousTrack and a skipBackward as they both occupy the left position.

There are seekForward / seekBackward commands that need a prevTrack and nextTrack command to be triggered. When you set up both then a single tap triggers next / previous and a press and hold triggers a begin seek and an end seek when you lift your finger.

    // Doesn’t show unless prevTrack is enabled
    MPRemoteCommand *seekBackwardCommand = [rcc seekBackwardCommand];
    [seekBackwardCommand setEnabled:YES];
    [seekBackwardCommand addTarget:self action:@selector(seekEvent:)];

    // Doesn’t show unless nextTrack is enabled
    MPRemoteCommand *seekForwardCommand = [rcc seekForwardCommand];
    [seekForwardCommand setEnabled:YES];
    [seekForwardCommand addTarget:self action:@selector(seekEvent:)];

-(void) seekEvent: (MPSeekCommandEvent *) seekEvent
{
    if (seekEvent.type == MPSeekCommandEventTypeBeginSeeking) {
        NSLog(@"Begin Seeking");
    }
    if (seekEvent.type == MPSeekCommandEventTypeEndSeeking) {
        NSLog(@"End Seeking");
    }
}

There is also a feedback mechanism that I haven’t seen before (occupies left position)

    MPFeedbackCommand *likeCommand = [rcc likeCommand];
    [likeCommand setEnabled:YES];
    [likeCommand setLocalizedTitle:@"I love it"];  // can leave this out for default
    [likeCommand addTarget:self action:@selector(likeEvent:)];

    MPFeedbackCommand *dislikeCommand = [rcc dislikeCommand];
    [dislikeCommand setEnabled:YES];
    [dislikeCommand setActive:YES];
    [dislikeCommand setLocalizedTitle:@"I hate it"]; // can leave this out for default
    [dislikeCommand addTarget:self action:@selector(dislikeEvent:)];

    BOOL userPreviouslyIndicatedThatTheyDislikedThisItemAndIStoredThat = YES;

    if (userPreviouslyIndicatedThatTheyDislikedThisItemAndIStoredThat) {
        [dislikeCommand setActive:YES];
    }

    MPFeedbackCommand *bookmarkCommand = [rcc bookmarkCommand];
    [bookmarkCommand setEnabled:YES];
    [bookmarkCommand addTarget:self action:@selector(bookmarkEvent:)];

// Feedback events also have a "negative" property but Command Center always returns not negative
-(void)dislikeEvent: (MPFeedbackCommandEvent *)feedbackEvent
{
    NSLog(@"Mark the item disliked");
}

-(void)likeEvent: (MPFeedbackCommandEvent *)feedbackEvent
{
    NSLog(@"Mark the item liked");
}

-(void)bookmarkEvent: (MPFeedbackCommandEvent *)feedbackEvent
{
    NSLog(@"Bookmark the item or playback position");
}

This displays three horizontal bars and brings up an alert sheet - you can highlight these individually by setting the active property.

There is also a rating command defined - but I couldn't get this to show in the Command Center

//    MPRatingCommand *ratingCommand = [rcc ratingCommand];
//    [ratingCommand setEnabled:YES];
//    [ratingCommand setMinimumRating:0.0];
//    [ratingCommand setMaximumRating:5.0];
//    [ratingCommand addTarget:self action:@selector(ratingEvent:)];

and a playback rate change command - but again couldn’t get this to show in Command Center

//    MPChangePlaybackRateCommand *playBackRateCommand = [rcc changePlaybackRateCommand];
//    [playBackRateCommand setEnabled:YES];
//    [playBackRateCommand setSupportedPlaybackRates:@[@(1),@(1.5),@(2)]];
//    [playBackRateCommand addTarget:self action:@selector(remoteControlReceivedWithEvent:)];

There is also a block-based target action mechanism if you prefer

// @property (strong, nonatomic) id likeHandler;
    self.likeHandler = [likeCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent *event) {
        NSLog(@"They like it");
        return MPRemoteCommandHandlerStatusSuccess;  // or fail or no such content
    }];

One final point to be aware of: If you have registered to receive remote events via [[UIApplication sharedApplication] beginReceivingRemoteControlEvents]; then some of these commands also trigger events in the - (void)remoteControlReceivedWithEvent:(UIEvent *)receivedEvent handler. These are UIEvents though with type UIEventTypeRemoteControl and a subtype to distinguish the event. You can't mix and match these with MPRemoteCommandEvents in this method. There are hints that MPRemoteCommandEvents will replace the UIEvents at some point.

All of this based on trial and error so feel free to correct.

Gareth

Answer 3

For Swift developers

import MediaPlayer

let rcc = MPRemoteCommandCenter.shared()

let skipBackwardCommand = rcc.skipBackwardCommand
skipBackwardCommand.isEnabled = true
skipBackwardCommand.addTarget(handler: skipBackward)
skipBackwardCommand.preferredIntervals = [42]

let skipForwardCommand = rcc.skipForwardCommand
skipForwardCommand.isEnabled = true
skipForwardCommand.addTarget(handler: skipForward)
skipForwardCommand.preferredIntervals = [42]

func skipBackward(_ event: MPRemoteCommandEvent) -> MPRemoteCommandHandlerStatus {
    guard let command = event.command as? MPSkipIntervalCommand else {
        return .noSuchContent
    }

    let interval = command.preferredIntervals[0]

    print(interval) //Output: 42

    return .success
}

func skipForward(_ event: MPRemoteCommandEvent) -> MPRemoteCommandHandlerStatus {
    guard let command = event.command as? MPSkipIntervalCommand else {
        return .noSuchContent
    }

    let interval = command.preferredIntervals[0]

    print(interval) //Output: 42

    return .success
}

Other command would be the similar and they can be checked here

Answer 4

Apple has no documentation because there is no way to change this. Again, Apple is keeping the best stuff to itself (Siri comes to mind also).

The jailbroken version supports changing Control Center buttons, which I found on this site. I have a feeling that you want to use this app on the actual iOS 7, not a jailbroken version, so this does not help you at all.

These private API's get in the way of developing good apps way too often. Unless Apple gives us more freedom to use currently-private API's, you are out of luck.