QQ音樂播放的過程中，鎖屏狀態下的效果如下:

也就是說，QQ音樂播放過程中，新增鎖屏遠端事件的監聽。

本文只記錄本人知道的小知識點，不提供完整的程式碼。

實現的原理：

（1）獲取鎖屏歌曲資訊中心：MPNowPlayingInfoCenter

（2）設定鎖屏下要顯示的歌曲的資訊

（3）啟動遠端事件的監聽

1.MPNowPlayingInfoCenter簡要說明：

（1）官方文件對MPNowPlayingInfoCenter的解說如下：

上面那段話大體的意思如下：

　　另外，當前播放資訊中心還提供了一個方法和一個屬性如下：

/// Returns the default now playing info center.
/// The default center holds now playing info about the current application.
+ (MPNowPlayingInfoCenter *)defaultCenter;/// The current now playing info for the center.
/// Setting the info to nil will clear it.
@property (nonatomic, copy, nullable) NSDictionary<NSString *, id> *nowPlayingInfo;

　　也就是說，可以用defaultCenter來獲取當前的MPNowPlayingInfoCenter，然後在nowPlayingInfo 以字典的形式設定 鎖屏中的歌曲資訊。

　　其中，這個類，還提供了一些額外的元組屬性，如下：

　　  MP_EXTERN NSString *const MPNowPlayingInfoPropertyElapsedPlaybackTime  當前時間 NSNumber
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyPlaybackRate
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyDefaultPlaybackRate
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyPlaybackQueueIndex
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyPlaybackQueueCount
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyChapterNumber
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyChapterCount
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyAvailableLanguageOptions   MPNowPlayingInfoLanguageOptionGroup
     MP_EXTERN NSString *const MPNowPlayingInfoPropertyCurrentLanguageOptions

　　找到了一個對這些屬性解說不錯的文件：

　　蹩腳英文翻譯系列:（未標註版本的鍵均為iOS8及以下可用）

2.鎖屏下要顯示歌曲資訊的設定

　　從上文中，已經可以知道，用

MPNowPlayingInfoCenter *center = [MPNowPlayingInfoCenter defaultCenter];

來獲取鎖屏資訊控制中心，然後把鎖屏情況下要顯示的圖片、歌曲名字、歌手、歌詞、時間等資訊以字典的形式賦值給center的nowPlayInfo屬性。

示例程式碼如下：

　　MPNowPlayingInfoCenter *center = [MPNowPlayingInfoCenter defaultCenter];
    NSMutableDictionary *infoDic = [NSMutableDictionary dictionary];
    [infoDic setObject:@"泡沫" forKey:MPMediaItemPropertyAlbumTitle];
    [infoDic setObject:@"歌手" forKey:MPMediaItemPropertyArtist];
    [infoDic setObject:[[MPMediaItemArtwork alloc] initWithImage:[UIImage imageNamed:@"61149b0491243c749fc871e67550a7f6"]] forKey:MPMediaItemPropertyArtwork];
    [infoDic setObject:@"200" forKey:MPMediaItemPropertyPlaybackDuration];
    [infoDic setObject:@"歌詞" forKey:MPMediaItemPropertyTitle];
    center.nowPlayingInfo = infoDic;

3.鎖屏遠端事件的監聽的簡要說明：

（1）ios71.版本

　　可以用的是[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

　　然後監聽remoteControlReceivedWithEvent：這個方法，

　　event的類中有UIEventSubtype的subtype。

　　subtype的型別如下：

typedef NS_ENUM(NSInteger, UIEventSubtype) {
    // available in iPhone OS 3.0
    UIEventSubtypeNone                              = 0,
    
    // for UIEventTypeMotion, available in iPhone OS 3.0
    UIEventSubtypeMotionShake                       = 1,
    
    // for UIEventTypeRemoteControl, available in iOS 4.0
    UIEventSubtypeRemoteControlPlay                 = 100,   //播放
    UIEventSubtypeRemoteControlPause                = 101,   //暫停
    UIEventSubtypeRemoteControlStop                 = 102,   //停止
    UIEventSubtypeRemoteControlTogglePlayPause      = 103,   //耳機上的播放暫停命令
    UIEventSubtypeRemoteControlNextTrack            = 104,   //下一首
    UIEventSubtypeRemoteControlPreviousTrack        = 105,   //上一首
    UIEventSubtypeRemoteControlBeginSeekingBackward = 106,   //開始後退
    UIEventSubtypeRemoteControlEndSeekingBackward   = 107,   //後退結束
    UIEventSubtypeRemoteControlBeginSeekingForward  = 108,   //開始快進
    UIEventSubtypeRemoteControlEndSeekingForward    = 109,   //快進結束
};

- (void)remoteControlReceivedWithEvent:(UIEvent *)event {

NSLog(@"---event.type = %ld", (long)event.subtype);

　//在這裡面監聽操作的型別

}

（2）iOS7.1以後

　　可以使用MPRemoteCommandCenter這個類的方法，這個類提供了一個類方法：sharedCommandCenter；

　　提供一個不錯可參考的連結：https://www.jianshu.com/p/b9cc97db16b8

　　MPRemoteCommandCenter是獲取到這個單例物件後，使用共享的這個MPRemoteCommand物件，用於響應各種遠端控制事件配置自己的需求。
如：像網易雲音樂一樣，在鎖屏以及多媒體系統UI介面配置滑動播放進度（seekTime），下一曲，上一曲，喜歡，不喜歡等配置；　　　　

　　MPRemoteCommandCenter提供的配置資訊如下：

// Playback Commands
@property (nonatomic, readonly) MPRemoteCommand *pauseCommand;   //暫停
@property (nonatomic, readonly) MPRemoteCommand *playCommand;    //播放
@property (nonatomic, readonly) MPRemoteCommand *stopCommand;    //停止
@property (nonatomic, readonly) MPRemoteCommand *togglePlayPauseCommand;  //耳機線控制暫停和播放
@property (nonatomic, readonly) MPRemoteCommand *enableLanguageOptionCommand MP_API(ios(9.0), macos(10.12.2));  //不知
@property (nonatomic, readonly) MPRemoteCommand *disableLanguageOptionCommand MP_API(ios(9.0), macos(10.12.2)); //不知
@property (nonatomic, readonly) MPChangePlaybackRateCommand *changePlaybackRateCommand;     //不知
@property (nonatomic, readonly) MPChangeRepeatModeCommand *changeRepeatModeCommand;         //不知
@property (nonatomic, readonly) MPChangeShuffleModeCommand *changeShuffleModeCommand;       不知

// Previous/Next Track Commands
@property (nonatomic, readonly) MPRemoteCommand *nextTrackCommand;    //下一首
@property (nonatomic, readonly) MPRemoteCommand *previousTrackCommand;  //上一首

// Skip Interval Commands
@property (nonatomic, readonly) MPSkipIntervalCommand *skipForwardCommand;  //快進幾秒（如果與下一首同時設定，優先顯示快進）
@property (nonatomic, readonly) MPSkipIntervalCommand *skipBackwardCommand; //快退幾秒（如果與上一首同時設定，優先顯示快退）

// Seek Commands
@property (nonatomic, readonly) MPRemoteCommand *seekForwardCommand;   //不知
@property (nonatomic, readonly) MPRemoteCommand *seekBackwardCommand;  //不知
@property (nonatomic, readonly) MPChangePlaybackPositionCommand *changePlaybackPositionCommand MP_API(ios(9.1), macos(10.12.2));

// Rating Command
@property (nonatomic, readonly) MPRatingCommand *ratingCommand;   //設定倍速，不知道在哪裡顯示

// Feedback Commands
// These are generalized to three distinct actions. Your application can provide
// additional context about these actions with the localizedTitle property in
// MPFeedbackCommand.
@property (nonatomic, readonly) MPFeedbackCommand *likeCommand;  //設定喜歡
@property (nonatomic, readonly) MPFeedbackCommand *dislikeCommand;  //設定不喜歡 
@property (nonatomic, readonly) MPFeedbackCommand *bookmarkCommand;  //新增標籤

　　設定的方式如下：

　 MPRemoteCommandCenter *rcc = [MPRemoteCommandCenter sharedCommandCenter];
    //新增暫停監聽
   [rcc.pauseCommand addTarget:self action:@selector(playOrPauseEvent:)];

整體的程式碼如下：

//
//  ViewController.m
//  音效播放
//
//  Created by 珠珠 on 2019/10/31.
//  Copyright © 2019 珠珠. All rights reserved.
//

#import "ViewController.h"

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


@interface ViewController ()

@property (nonatomic,strong) AVAudioPlayer *player ;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //設定音樂的後臺播放，注意background mode中需要勾選上
    AVAudioSession *session = [AVAudioSession sharedInstance];
    [session setCategory:AVAudioSessionCategoryPlayback error:nil];

    //獲取資訊中心
    MPNowPlayingInfoCenter *center = [MPNowPlayingInfoCenter defaultCenter];
    //設定要鎖屏要顯示的基本資訊
    NSMutableDictionary *infoDic = [NSMutableDictionary dictionary];
    [infoDic setObject:@"泡沫" forKey:MPMediaItemPropertyAlbumTitle];
    [infoDic setObject:@"歌手" forKey:MPMediaItemPropertyArtist];
    [infoDic setObject:[[MPMediaItemArtwork alloc] initWithImage:[UIImage imageNamed:@"61149b0491243c749fc871e67550a7f6"]] forKey:MPMediaItemPropertyArtwork];
    [infoDic setObject:@"200" forKey:MPMediaItemPropertyPlaybackDuration];
    [infoDic setObject:@"歌詞" forKey:MPMediaItemPropertyTitle];
    //給資訊中心賦值
    center.nowPlayingInfo = infoDic;
    //新增遠端事件監聽
    NSString *version= [UIDevice currentDevice].systemVersion;
    if(version.doubleValue <=7.1) {
        //iOS版本7.1以下的建議使用這個方法
        [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    }else{
        //iOS版本7.1以上的的建議使用這個方法
         [self addRemoteCommandCenter];
    }
}



#pragma mark - 基本播放操作
//開始播放
- (IBAction)player:(id)sender {
    [self.player play];
    
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    [self.view addSubview:view];
}

//暫停播放
- (IBAction)pause:(id)sender {
    [self.player pause];
}

//停止播放
- (IBAction)stop:(id)sender {
    [self.player stop];
}

//前進5秒
- (IBAction)qianJin5s:(id)sender {
    self.player.currentTime += 5;
}

//後退5秒
- (IBAction)houTui5s:(id)sender {
    self.player.currentTime -= 5;
}

//2倍速度播放
- (IBAction)faster:(id)sender {
    self.player.rate = 2;
}

//播放一次
- (IBAction)playOnce:(id)sender {
    self.player.numberOfLoops = 0;
}

//播放3次
- (IBAction)playThirst:(id)sender {
    self.player.numberOfLoops = 2;
}

//迴圈播放
- (IBAction)playAllTheTime:(id)sender {
    self.player.numberOfLoops = -1;
}

//聽筒播放
- (IBAction)tingTongPlay:(id)sender {
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:0 error:nil];
}

//揚聲器播放
- (IBAction)outSpeakerPlayer:(id)sender {
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker error:nil];
}

#pragma mark - MPRemoteCommandCenter相關的方法
- (void)addRemoteCommandCenter {
    MPRemoteCommandCenter *rcc = [MPRemoteCommandCenter sharedCommandCenter];
    //新增暫停監聽
    [rcc.pauseCommand addTarget:self action:@selector(playOrPauseEvent:)];
    //新增播放監聽
    [rcc.playCommand addTarget:self action:@selector(playOrPauseEvent:)];
    //下一首
    [rcc.nextTrackCommand addTarget:self action:@selector(nextCommandEvent:)];
    //上一首
    [rcc.previousTrackCommand addTarget:self action:@selector(previousTrackCommand:)];
    //耳機暫停和播放的監聽
    [rcc.togglePlayPauseCommand addTarget:self action:@selector(togglePlayPauseCommand:)];
    //快進(如果同時設定了下一首和快進，那麼鎖屏下只會顯示快進的按鈕)
    [rcc.skipForwardCommand addTarget:self action:@selector(handleSkipForward:)];
    [rcc.skipForwardCommand setPreferredIntervals:@[@(20)]];    // 設定快進時間(最大 99)
    //快退(如果同時設定了下一首和後退，那麼鎖屏下只會顯示快退的按鈕)
    [rcc.skipBackwardCommand addTarget:self action:@selector(handleSkipBack:)];
    [rcc.skipBackwardCommand setPreferredIntervals:@[@20]];     // 設定快退時間（最大99）
    
//    [self feedbackCommand]
}


- (void)playOrPauseEvent:(MPRemoteCommand *)command
{
    NSLog(@"播放或者暫停");
    if (self.player.isPlaying) {
        [self.player pause];
    }else {
        [self.player play];
    }
}

- (void)nextCommandEvent:(MPRemoteCommand *)command
{
    NSLog(@"%@",@"下一曲");
}

- (void)previousTrackCommand:(MPRemoteCommand *)command
{
    NSLog(@"%@",@"上一曲");
}

- (void)togglePlayPauseCommand:(MPRemoteCommand *)command {
    NSLog(@"耳機的開始和暫停");
    if (self.player.isPlaying) {
        [self.player pause];
    }else {
        [self.player play];
    }
}

- (void)handleSkipForward:(MPRemoteCommand *)command
{
    NSLog(@"快進%@",command);
}

- (void)handleSkipBack:(MPRemoteCommand *)command
{
    NSLog(@" 快退%@",command);
}


-(void)feedbackCommand:(MPRemoteCommandCenter *)rcc
{
    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:)];
}

-(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");
}


#pragma mark - 遠端事件的監聽:[[UIApplication sharedApplication] beginReceivingRemoteControlEvents]
- (void)remoteControlReceivedWithEvent:(UIEvent *)event {
    NSLog(@"---event.type = %ld", (long)event.subtype);
}


#pragma mark - 懶載入播放器
- (AVAudioPlayer *)player {
    if (!_player) {
        //獲取播放的路徑 paomo.mp3   2018-11-27 10_36_51 1.wav
        NSURL *path = [[NSBundle mainBundle] URLForResource:@"paomo.mp3" withExtension:nil];
        //根據路徑建立播放物件
        AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:path error:nil];

        //如果這個屬性不設定的話，那麼不能設定倍速播放的功能
        player.enableRate = YES;
        
        //準備播放
        [player prepareToPlay];
        _player = player;

    }
    return _player;
}

@end

另參考連結：http://www.cocoachina.com/articles/15767

from：https://www.cnblogs.com/lyz0925/p/11792667.html