概述

功能描述：锁屏歌曲信息、控制台远程控制音乐播放：暂停/播放、上一首/下一首、快进/快退、列表菜单弹框和拖拽控制台的进度条调节进度（结合了QQ音乐和网易云音乐在锁屏状态下的效果）、歌词解析并随音乐滚动显示。

详细

功能描述：锁屏歌曲信息、控制台远程控制音乐播放：暂停/播放、上一首/下一首、快进/快退、列表菜单弹框和拖拽控制台的进度条调节进度（结合了QQ音乐和网易云音乐在锁屏状态下的效果）、歌词解析并随音乐滚动显示。

第一部分：锁屏效果包括：锁屏歌曲信息和远程控制音乐播放

① 锁屏歌曲信息显示

//展示锁屏歌曲信息：图片、歌词、进度、歌曲名、演唱者、专辑、（歌词是绘制在图片上的）
- (void)showLockScreenTotaltime:(float)totalTime andCurrentTime:(float)currentTime andLyricsPoster:(BOOL)isShow{   NSMutableDictionary * songDict = [[NSMutableDictionary alloc] init];    //设置歌曲题目[songDict setObject:@"多幸运" forKey:MPMediaItemPropertyTitle];    //设置歌手名[songDict setObject:@"韩安旭" forKey:MPMediaItemPropertyArtist];    //设置专辑名[songDict setObject:@"专辑名" forKey:MPMediaItemPropertyAlbumTitle];    //设置歌曲时长[songDict setObject:[NSNumber numberWithDouble:totalTime]  forKey:MPMediaItemPropertyPlaybackDuration];    //设置已经播放时长[songDict setObject:[NSNumber numberWithDouble:currentTime] forKey:MPNowPlayingInfoPropertyElapsedPlaybackTime];   UIImage * lrcImage = [UIImage imageNamed:@"backgroundImage5.jpg"];    if (isShow) {             //制作带歌词的海报if (!_lrcImageView) {_lrcImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 480,800)];}      if (!_lockScreenTableView) {_lockScreenTableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 800 - 44 * 7 + 20, 480, 44 * 3) style:UITableViewStyleGrouped];_lockScreenTableView.dataSource = self;_lockScreenTableView.delegate = self;_lockScreenTableView.separatorStyle = NO;_lockScreenTableView.backgroundColor = [UIColor clearColor];[_lockScreenTableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cellID"];}        //主要为了把歌词绘制到图片上，已达到更新歌词的目的[_lrcImageView addSubview:self.lockScreenTableView];_lrcImageView.image = lrcImage;_lrcImageView.backgroundColor = [UIColor blackColor];        //获取添加了歌词数据的海报图片UIGraphicsBeginImageContextWithOptions(_lrcImageView.frame.size, NO, 0.0);     CGContextRef context = UIGraphicsGetCurrentContext();[_lrcImageView.layer renderInContext:context];lrcImage = UIGraphicsGetImageFromCurrentImageContext();_lastImage = lrcImage;     UIGraphicsEndImageContext();}else{       if (_lastImage) {lrcImage = _lastImage;}}    //设置显示的海报图片[songDict setObject:[[MPMediaItemArtwork alloc] initWithImage:lrcImage]forKey:MPMediaItemPropertyArtwork];   //加入正在播放媒体的信息中心[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:songDict];}

② 远程控制音乐播放

在此之前需先满足后台播放音乐的条件:

    //后台播放音频设置,需要在Capabilities->Background Modes中勾选Audio,Airplay,and Picture in Picture ，如下图1、2AVAudioSession *session = [AVAudioSession sharedInstance];[session setActive:YES error:nil];[session setCategory:AVAudioSessionCategoryPlayback error:nil];

• 在iOS7.1之前, App如果需要在锁屏界面开启和监控远程控制事件,可以通过重写- (void)remoteControlReceivedWithEvent:(UIEvent *)event这个方法来捕获远程控制事件，并根据event.subtype来判别指令意图并作出反应。具体用法如下：

//在具体的控制器或其它类中捕获处理远程控制事件,当远程控制事件发生时触发该方法, 该方法属于UIResponder类，iOS 7.1 之前经常用- (void)remoteControlReceivedWithEvent:(UIEvent *)event{    NSLog(@"%ld",event.type);[[NSNotificationCenter defaultCenter] postNotificationName:@"songRemoteControlNotification" object:self userInfo:@{@"eventSubtype":@(event.subtype)}];
} /* iOS 7.1之前*///让App开始接收远程控制事件, 该方法属于UIApplication类[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];     //结束远程控制,需要的时候关闭//     [[UIApplication sharedApplication] endReceivingRemoteControlEvents];//处理控制台的暂停/播放、上/下一首事件[[NSNotificationCenter defaultCenter] addObserverForName:@"songRemoteControlNotification" object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *notification) {  NSInteger  eventSubtype = [notification.userInfo[@"eventSubtype"] integerValue];  switch (eventSubtype) {    case UIEventSubtypeRemoteControlNextTrack:    NSLog(@"下一首");   break;   case UIEventSubtypeRemoteControlPreviousTrack:   NSLog(@"上一首");  break;  case  UIEventSubtypeRemoteControlPause:[self.player pause];    break;    case  UIEventSubtypeRemoteControlPlay:[self.player play];  break;     //耳机上的播放暂停case  UIEventSubtypeRemoteControlTogglePlayPause:   NSLog(@"播放或暂停");     break;     //后退case UIEventSubtypeRemoteControlBeginSeekingBackward:  break;    case UIEventSubtypeRemoteControlEndSeekingBackward:  NSLog(@"后退");    break;     //快进case UIEventSubtypeRemoteControlBeginSeekingForward:    break;    case UIEventSubtypeRemoteControlEndSeekingForward:   NSLog(@"前进");  break;    default:  break;}}];

• 在iOS7.1之后，出现了MPRemoteCommandCenter、MPRemoteCommand 及其相关的一些类 ，锁屏界面开启和监控远程控制事件就更方便了，而且还扩展了一些新功能：网易云音乐的列表菜单弹框功能和QQ音乐的拖拽控制台的进度条调节进度功能等等.....
  官方文档：https://developer.apple.com/documentation/mediaplayer/mpremotecommandcenter

   //锁屏界面开启和监控远程控制事件- (void)createRemoteCommandCenter{/**///远程控制命令中心 iOS 7.1 之后  详情看官方文档：https://developer.apple.com/documentation/mediaplayer/mpremotecommandcenterMPRemoteCommandCenter *commandCenter = [MPRemoteCommandCenter sharedCommandCenter];//   MPFeedbackCommand对象反映了当前App所播放的反馈状态. MPRemoteCommandCenter对象提供feedback对象用于对媒体文件进行喜欢, 不喜欢, 标记的操作. 效果类似于网易云音乐锁屏时的效果//添加喜欢按钮MPFeedbackCommand *likeCommand = commandCenter.likeCommand;likeCommand.enabled = YES;likeCommand.localizedTitle = @"喜欢";[likeCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {NSLog(@"喜欢");return MPRemoteCommandHandlerStatusSuccess;}];//添加不喜欢按钮，假装是“上一首”MPFeedbackCommand *dislikeCommand = commandCenter.dislikeCommand;dislikeCommand.enabled = YES;dislikeCommand.localizedTitle = @"上一首";[dislikeCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {NSLog(@"上一首");return MPRemoteCommandHandlerStatusSuccess;}];//标记MPFeedbackCommand *bookmarkCommand = commandCenter.bookmarkCommand;bookmarkCommand.enabled = YES;bookmarkCommand.localizedTitle = @"标记";[bookmarkCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {NSLog(@"标记");return MPRemoteCommandHandlerStatusSuccess;}];//    commandCenter.togglePlayPauseCommand 耳机线控的暂停/播放[commandCenter.pauseCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {[self.player pause];return MPRemoteCommandHandlerStatusSuccess;}];[commandCenter.playCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {[self.player play];return MPRemoteCommandHandlerStatusSuccess;}];//    [commandCenter.previousTrackCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {//        NSLog(@"上一首");//        return MPRemoteCommandHandlerStatusSuccess;//    }];[commandCenter.nextTrackCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {NSLog(@"下一首");return MPRemoteCommandHandlerStatusSuccess;}];//快进//    MPSkipIntervalCommand *skipBackwardIntervalCommand = commandCenter.skipForwardCommand;//    skipBackwardIntervalCommand.preferredIntervals = @[@(54)];//    skipBackwardIntervalCommand.enabled = YES;//    [skipBackwardIntervalCommand addTarget:self action:@selector(skipBackwardEvent:)];//在控制台拖动进度条调节进度（仿QQ音乐的效果）[commandCenter.changePlaybackPositionCommand addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {CMTime totlaTime = self.player.currentItem.duration;MPChangePlaybackPositionCommandEvent * playbackPositionEvent = (MPChangePlaybackPositionCommandEvent *)event;[self.player seekToTime:CMTimeMake(totlaTime.value*playbackPositionEvent.positionTime/CMTimeGetSeconds(totlaTime), totlaTime.timescale) completionHandler:^(BOOL finished) {}];return MPRemoteCommandHandlerStatusSuccess;}];}-(void)skipBackwardEvent: (MPSkipIntervalCommandEvent *)skipEvent
{NSLog(@"快进了 %f秒", skipEvent.interval);
}

第二部分：歌词解析

• 根据上图的歌词样式，思路就是：先根据换行符“\n“分割字符串，获得包含每一行歌词字符串的数组，然后解析每一行歌词字符，获得时间点和对应的歌词，再用创建的歌词对象wslLrcEach来存储时间点和歌词，最后得到一个存储wslLrcEach对象的数组.

• //每句歌词对象
  @interface wslLrcEach : NSObject
  @property(nonatomic, assign) NSUInteger time ;
  @property(nonatomic, copy) NSString * lrc ;
  @end

  接下来就是要让歌词随歌曲的进度来滚动显示,主要代码如下：

   self.tableView  显示歌词的currentTime  当前播放时间点self.currentRow  当前时间点歌词的位置//歌词滚动显示for ( int i = (int)(self.lrcArray.count - 1); i >= 0 ;i--) {wslLrcEach * lrc = self.lrcArray[i];if (lrc.time < currentTime) {self.currentRow = i;[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow: self.currentRow inSection:0] atScrollPosition:UITableViewScrollPositionMiddle animated:YES];[self.tableView reloadData];break;}}

第三部分：项目截图