ios开发之MPNowPlayingInfoCenter 锁屏显示正在播放的音乐

逃离我推掉我的手 2022-09-20 12:55 362阅读 0赞

# 今天在床上玩唱吧,听着歌锁屏了,当点亮屏幕的时候,锁屏页面出现了我正在听得歌曲 壁纸也换成了唱吧里面的歌手图片.做ios好几年了,从没有做过这个需求 于是好奇就翻看ios的[API文档][API]找到了这个类. #

如下图

![a43af4ffjw1e8r3az0tbaj20g50litai.jpg][] ![a43af4ffjw1e8r3b00x7aj20gj05wq3e.jpg][]

## MPNowPlayingInfoCenter 解释 ##

> 即时播放中心能够用于播放APP中正在播放的媒体信息.  
> 播放的信息会显示在锁屏页面和多任务管理页面.如果用户是用airplay播放的话 会自动投射到相应的设备上.

[下载源码][Link 1]

## 开始动手 ##

### 让App支持后台运行 ###

先创建工程,因为是audio 类型的app 需要支持后台播放 所以得要在plist 中声明属性.  
添加如下属性

Required background modes -> App plays audio  
如下图

![a43af4ffjw1e8r45ojlcuj20l80a2q4l.jpg][]

### 添加播放的Frame ###

1.  AVFoundation.framework
2.  MediaPlayer.framework

![a43af4ffjw1e8r4757worj208c03vq2z.jpg][]

### 开始代码吧 ###

首先创建一个ViewController 和一个用于播放的按钮 playButton

@interface ViewController : UIViewController {
          
    
    IBOutlet UIButton *playButton;
    
    }
    
    @property (nonatomic, retain) IBOutlet UIButton *playButton;
    
    -(IBAction)playButtonPress:(id)sender;

加入播放用的控件audioPlayer 和其相应的头文件

#import <MediaPlayer/MPNowPlayingInfoCenter.h>
    #import <MediaPlayer/MPMediaItem.h>
    #import <AVFoundation/AVFoundation.h>
    MPMoviePlayerController *audioPlayer;
    
    @property (nonatomic, retain) MPMoviePlayerController *audioPlayer;
    
    @synthesize playButton, audioPlayer;

在viewDidLoad 中 我们要把AudioPlayer 进行初始化 此处加载网络上的一首音频

[[AVAudioSession sharedInstance] setDelegate: self];
    
    NSError *myErr;
    
    // Initialize the AVAudioSession here.
    if (![[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:&myErr]) {
        // Handle the error here.
        NSLog(@"Audio Session error %@, %@", myErr, [myErr userInfo]);
    }
    else{
        // Since there were no errors initializing the session, we'll allow begin receiving remote control events
        [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    }
    
        //initialize our audio player
        audioPlayer = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL URLWithString:@"http://www.cocoanetics.com/files/Cocoanetics_031.mp3"]];
    
        [audioPlayer setShouldAutoplay:NO];
        [audioPlayer setControlStyle: MPMovieControlStyleEmbedded];
        audioPlayer.view.hidden = YES;
    
        [audioPlayer prepareToPlay];

点击按钮开始播放,注意因为MPNowPlayingInfoCenter只支持5.0+ 所以为了防止低版本使用 巧妙的应用了NSClassFromString进行了判断

- (IBAction)playButtonPress:(id)sender {
    
        [audioPlayer play];
    
        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 ];
        }
    }

--------------------

[参考 ][Link 2][http://jaysonlane.net/tech-blog/2012/04/lock-screen-now-playing-with-mpnowplayinginfocenter/][Link 2]

更多 [2][]

[API]: https://developer.apple.com/library/ios/documentation/mediaplayer/reference/MPNowPlayingInfoCenter_Class/Reference/Reference.html
[a43af4ffjw1e8r3az0tbaj20g50litai.jpg]: http://ww3.sinaimg.cn/mw690/a43af4ffjw1e8r3az0tbaj20g50litai.jpg
[a43af4ffjw1e8r3b00x7aj20gj05wq3e.jpg]: /images/20220828/a1745bc2d1ae498e8ba47c1a49745117.png
[Link 1]: https://github.com/hufeng825/LockScreenInfo.git
[a43af4ffjw1e8r45ojlcuj20l80a2q4l.jpg]: /images/20220828/0ac8134edc4e43d5833a767ce8b06f12.png
[a43af4ffjw1e8r4757worj208c03vq2z.jpg]: /images/20220828/5beb492b164a49ffae0573cdac8c0f21.png
[Link 2]: http://jaysonlane.net/tech-blog/2012/04/lock-screen-now-playing-with-mpnowplayinginfocenter/
[2]: http://blog.csdn.net/hufengvip/article/details/11823199#