实现音乐的后台播放。以及播放时，能够控制其暂停，下一首等操作，以及锁屏图片歌曲名等的显示

此实例须要真机调试。效果图例如以下：

project下载：githubproject下载

实现步骤：

1、首先改动info.plist

2、其次引入两个须要的框架

#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) {  //推断是否为远程控制

        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，比如歌曲名字。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];

}