iOS音乐后台播放及锁屏信息显示

实现音乐的后台播放，以及播放时，可以控制其暂停，下一首等操作，以及锁屏图片歌曲名等的显示
此实例需要真机调试，效果图如下：

工程下载：github工程下载

实现步骤：
1、首先修改info.plist

2、其次引入两个需要的框架

#import <AVFoundation/AVFoundation.h>
#import <MediaPlayer/MediaPlayer.h>

3、设置播放器及后台播放

- (void)viewDidLoad {
    [super viewDidLoad];
//    设置后台播放
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];

//    设置播放器
    NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"那些花儿" ofType:@"mp3"] ];
    _player = [[AVPlayer alloc] initWithURL:url];
    [_player play];
    _isPlayingNow = YES;

    //后台播放显示信息设置
    [self setPlayingInfo];
}

#pragma mark - 接收方法的设置
- (void)remoteControlReceivedWithEvent:(UIEvent *)event {
    if (event.type == UIEventTypeRemoteControl) {  //判断是否为远程控制
        switch (event.subtype) {
            case  UIEventSubtypeRemoteControlPlay:
                if (!_isPlayingNow) {
                    [_player play];
                }
                _isPlayingNow = !_isPlayingNow;
                break;
            case UIEventSubtypeRemoteControlPause:
                if (_isPlayingNow) {
                    [_player pause];
                }
                _isPlayingNow = !_isPlayingNow;
                break;
            case UIEventSubtypeRemoteControlNextTrack:
                NSLog(@"下一首");
                break;
            case UIEventSubtypeRemoteControlPreviousTrack:
                NSLog(@"上一首 ");
                break;
            default:
                break;
        }
    }
}

4、设置后台播放时显示的东西，例如歌曲名字，图片等

- (void)setPlayingInfo {
//    <MediaPlayer/MediaPlayer.h>
    MPMediaItemArtwork *artWork = [[MPMediaItemArtwork alloc] initWithImage:[UIImage imageNamed:@"pushu.jpg"]];

    NSDictionary *dic = @{MPMediaItemPropertyTitle:@"那些花儿",
                          MPMediaItemPropertyArtist:@"朴树",
                          MPMediaItemPropertyArtwork:artWork
                          };
    [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:dic];
}

5、远程控制设置

- (void)viewDidAppear:(BOOL)animated {
//    接受远程控制
    [self becomeFirstResponder];
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}

- (void)viewDidDisappear:(BOOL)animated {
//    取消远程控制
    [self resignFirstResponder];
    [[UIApplication sharedApplication] endReceivingRemoteControlEvents];
}