如何在控制中心显示寻道持续时间

Question

如何将歌曲信息（例如歌曲名称和曲目时长）传递给控制中心。 播放器可以正常播放音乐，但播放和暂停控制也可以正常工作。

玩苹果的音乐应用

使用下面的代码玩我的应用程序，如何传递歌曲信息以显示它？

//AppDelegate
    -(void)setupAudio
    {
        // Set AVAudioSession
        NSError *sessionError = nil;
        [[AVAudioSession sharedInstance] setDelegate:self];
        [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:&sessionError];

        // Change the default output audio route
        UInt32 doChangeDefaultRoute = 1;
        AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryDefaultToSpeaker,
                                sizeof(doChangeDefaultRoute), &doChangeDefaultRoute);

            [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
            [self becomeFirstResponder];
    }

    //Make sure we can recieve remote control events
    - (BOOL)canBecomeFirstResponder {
        return YES;
    }

    - (void)remoteControlReceivedWithEvent:(UIEvent *)event
    {
        //if it is a remote control event handle it correctly
        if (event.type == UIEventTypeRemoteControl) {
            if (event.subtype == UIEventSubtypeRemoteControlPlay)
            {
                NSLog(@"UIEventSubtypeRemoteControlPlay");
                [[AppMusicPlayer sharedService]playAudio];
            }
            else if (event.subtype == UIEventSubtypeRemoteControlPause)
            {
                NSLog(@"UIEventSubtypeRemoteControlPause");
                [[AppMusicPlayer sharedService]pauseAudio];
            }
            else if (event.subtype == UIEventSubtypeRemoteControlTogglePlayPause)
            {
                NSLog(@"UIEventSubtypeRemoteControlTogglePlayPause");
            }
        }
    }

    AppMusicPlayer.m
    + (id) sharedService
    {
        static dispatch_once_t _singletonPredicate;
        static AppMusicPlayer *_sharedObject = nil;

        dispatch_once(&_singletonPredicate, ^{
            _sharedObject = [[AppMusicPlayer alloc]init];
        });

        return _sharedObject;
    }

    - (id)init
    {
        self = [super init];

        if (self) {
            // Work your initialising here as you normally would
        }

        return self;
    }

    - (void)playAudio
    {
        [self.audioPlayer play];
    }

    - (void)pauseAudio
    {
        NSLog(@"pause");
        [self.audioPlayer pause];
    }

    - (void)playAudioFromURL:(NSURL *)songURL
    {
        [self.audioPlayer stop];

        //Declare the audio file location and settup the player
        NSError *error;
        self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:songURL error:&error];
        [self.audioPlayer setNumberOfLoops:-1];

        if (error)
        {
            NSLog(@"%@", [error localizedDescription]);
               }
        else
        {
            //Load the audio into memory
            [self.audioPlayer prepareToPlay];
            [self.audioPlayer play];
        }
    }

-(void)setUpRemoteControl
{
    NSDictionary *nowPlaying = @{MPMediaItemPropertyArtist: songItem.artistName,
                                 MPMediaItemPropertyAlbumTitle: songItem.albumTitle,
                                 MPMediaItemPropertyPlaybackDuration:songItem.playbackDuration,
                                 MPNowPlayingInfoPropertyPlaybackRate:@1.0f,
                                 MPMediaItemPropertyArtwork:[songMedia valueForProperty:MPMediaItemPropertyArtwork]

                                 };

    [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:nowPlaying];
}

Answer 1

您正在播放 iPod 音乐库中的歌曲吗？ 如果是，那么您应该使用 MPMusicPlayerViewController，它为搜索栏属性和信息中心提供内置功能。

我可以在你的代码中看到你使用了 AVAudioPlayer， 我们只能使用 AVAudioPlayer 类设置以下详细信息，但无法在我们的应用程序中访问 seekbar 更改事件。

NSMutableDictionary *albumInfo = [[NSMutableDictionary alloc] init];
UIImage *artWork = [UIImage imageNamed:album.imageUrl];
[albumInfo setObject:album.title forKey:MPMediaItemPropertyTitle];
[albumInfo setObject:album.auther forKey:MPMediaItemPropertyArtist];
[albumInfo setObject:album.title forKey:MPMediaItemPropertyAlbumTitle];
[albumInfo setObject:artworkP forKey:MPMediaItemPropertyArtwork];
[albumInfo setObject:album.playrDur forKey:MPMediaItemPropertyPlaybackDuration]
[albumInfo setObject:album.elapsedTime forKey:MPNowPlayingInfoPropertyElapsedPlaybackTime]
[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:albumInfo]

这里我们需要根据需要的格式统计album.playrDur和album.elapsedTime。

Answer 2

你正在寻找这个：

- (IBAction)playButtonTouched:(id)sender {

   Class playingInfoCenter = NSClassFromString(@"MPNowPlayingInfoCenter");

    if (playingInfoCenter) {


        NSMutableDictionary *songInfo = [[NSMutableDictionary alloc] init];


        MPMediaItemArtwork *albumArt = [[MPMediaItemArtwork alloc] initWithImage: [UIImage imagedNamed:@"AlbumArt"]];

        [songInfo setObject:@"Audio Title" forKey:MPMediaItemPropertyTitle];
        [songInfo setObject:@"Audio Author" forKey:MPMediaItemPropertyArtist];
        [songInfo setObject:@"Audio Album" forKey:MPMediaItemPropertyAlbumTitle];
        [songInfo setObject:albumArt forKey:MPMediaItemPropertyArtwork];
        [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songInfo];


    }
}

Answer 3

我今天碰巧在做同样的事情，不知道答案，但在我的应用程序中，控制中心确实显示了应用程序名称。我希望能够显示我正在玩的东西的标题。我什至有一张我想展示的照片，比如专辑封面。我不认为我在做任何与你不同的事情，例如，我没有编写任何代码来向它发送应用名称。

等一下……我看到有一个叫做 MPNowPlayingInfoCenter 的东西，我们应该研究一下……

Answer 4

不确定，但这段代码可能对您有所帮助..

   - (void) handle_NowPlayingItemChanged: (id) notification
{
    MPMediaItem *currentItem = [musicPlayer nowPlayingItem];
    NSString *titleString = [currentItem valueForProperty:MPMediaItemPropertyTitle];
    if (titleString)
    {
        titleLabel.text = [NSString stringWithFormat:@"Title: %@",titleString];
    } 
    else 
    {
        titleLabel.text = @"Title: Unknown title";
    }
}