iOS 控制中心和音频播放

需求：在后台播放音频，特别是在直播间或录歌模式下播放音频的时候，只希望后台播放，并不希望后台控制。这里主要是针对这一问题的解决。
代码部分：
.h文件

//控制中心
//在后台播放音频文件，特别是在直播间或录歌模式下播放音频的时候，只希望后台播放，并不希望后台控制

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

typedef enum : NSUInteger {
    NoneEnabled,        //没有可用
    OnlyCenterButton,   //仅中间按钮显示
    AllEnabled,         //所有按钮都可用
} BackstageCtrlType;

typedef enum : NSUInteger {
    CenterButtonPlay,      //播放按钮 ▶️
    CenterButtonPause,     //暂停按钮 ⏸
    PreviousButton,        //左边按钮 ⏮
    NextButton,           //右边按钮 ⏭
} BackstageButtonType;

/**
 后台按钮点击回调

 @param buttonType 按钮类型
 */
typedef void(^BackstageButtonBlock)(BackstageButtonType buttonType);

@interface ControlCenter : NSObject
/**
 控制中心

 @return 控制中心单例
 */
+(instancetype)shareControlCenter;
/**
 开启后台对音频的控制
 */
-(void)openBackstageControlAudio;
/**
 配置后台按钮

 @param type 后台按钮类型
 */
-(void)configBackstageAudioButtons:(BackstageCtrlType)type;
/**
 本地音频文件时长

 @param fileUrl 路径
 @return 时长
 */
-(float)audioSoundDuration:(NSURL *)fileUrl;
/**
 配置控制中心歌曲信息
 
 @param title 歌曲名
 @param artist 歌手
 @param duration 播放时长
 @param artwork 图片
 */
-(void)configControlCenterSongInfo:(NSString *)title artist:(NSString *)artist playbackDuration:(double)duration artwork:(UIImage *)artwork;

/**
 后台按钮点击回调
 */
@property(nonatomic,copy)BackstageButtonBlock buttonCilckBlock;
@end

.m文件

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

@implementation ControlCenter
static ControlCenter *_instance;  //创建静态对象,防止外界访问

#pragma mark - system method
+(instancetype)allocWithZone:(struct _NSZone *)zone{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        if (_instance == nil) {
            _instance = [super allocWithZone:zone];
        }
    });
    return _instance;
}

#pragma mark - public method
+(instancetype)shareControlCenter{
    return  [[self alloc]init];
}
-(void)openBackstageControlAudio{
    //设置后台播放音频
    AVAudioSession *session = [AVAudioSession sharedInstance];
    [session setActive:YES error:nil];
    [session setCategory:AVAudioSessionCategoryPlayback error:nil];
    //开启响应后台控制
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}
-(void)configBackstageAudioButtons:(BackstageCtrlType)type{
    //注意:只有添加响应事件之后,在控制中心才会显示按钮;中间按钮暂停和播放都要添加事件
    MPRemoteCommand *playButton = [[MPRemoteCommandCenter sharedCommandCenter] playCommand]; //播放
    MPRemoteCommand *pauseButton = [[MPRemoteCommandCenter sharedCommandCenter] pauseCommand];  //暂停
    MPRemoteCommand *nextButton = [[MPRemoteCommandCenter sharedCommandCenter] nextTrackCommand];  //下一首
    MPRemoteCommand *previousButton = [[MPRemoteCommandCenter sharedCommandCenter] previousTrackCommand];  //上一首
    playButton.enabled = YES;
    pauseButton.enabled = YES;
    nextButton.enabled = YES;
    previousButton.enabled = YES;
    [playButton removeTarget:self action:@selector(playAction:)];
    [pauseButton removeTarget:self action:@selector(pauseAction:)];
    [nextButton removeTarget:self action:@selector(nextAction:)];
    [previousButton removeTarget:self action:@selector(previousAction:)];
    switch (type) {
        case NoneEnabled:
            playButton.enabled = NO;
            pauseButton.enabled = NO;
            [playButton addTarget:self action:@selector(playAction:)];
            [pauseButton addTarget:self action:@selector(pauseAction:)];
            break;
        case OnlyCenterButton:
            playButton.enabled = YES;
            pauseButton.enabled = YES;
            [playButton addTarget:self action:@selector(playAction:)];
            [pauseButton addTarget:self action:@selector(pauseAction:)];
            break;
        case AllEnabled:
            [playButton addTarget:self action:@selector(playAction:)];
            [pauseButton addTarget:self action:@selector(pauseAction:)];
            [nextButton addTarget:self action:@selector(nextAction:)];
            [previousButton addTarget:self action:@selector(previousAction:)];
            break;
        default:
            break;
    }
}
-(float)audioSoundDuration:(NSURL *)fileUrl{
    NSDictionary *options = @{AVURLAssetPreferPreciseDurationAndTimingKey: @YES};
    AVURLAsset *audioAsset = [AVURLAsset URLAssetWithURL:fileUrl options:options];
    CMTime audioDuration = audioAsset.duration;
    float audioDurationSeconds = CMTimeGetSeconds(audioDuration);
    return audioDurationSeconds;
}
-(void)configControlCenterSongInfo:(NSString *)title artist:(NSString *)artist playbackDuration:(double)duration artwork:(UIImage *)artwork{
    //注意： 如果你没配置歌曲信息，点击暂停，锁屏状态下的控制中心界面消失
    NSMutableDictionary *infoDic = [NSMutableDictionary dictionary];
    if (title.length) {         //设置歌曲题目
        [infoDic setObject:title forKey:MPMediaItemPropertyTitle];
    }
    if (artist.length) {    //设置歌手名
        [infoDic setObject:artist forKey:MPMediaItemPropertyArtist];
    }
    if (duration) {     //设置播放时间
        [infoDic setObject:[NSNumber numberWithDouble:duration] forKey:MPMediaItemPropertyPlaybackDuration];
    }
    if (artwork) {  //设置显示的图片
        [infoDic setObject:artwork forKey:MPMediaItemPropertyArtwork];
    }
    [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:infoDic];
}
#pragma mark - private method
-(void)playAction:(MPRemoteCommandEvent *)event{
    if (_buttonCilckBlock) {
        _buttonCilckBlock(CenterButtonPlay);
    }
}
-(void)pauseAction:(MPRemoteCommandEvent *)event{
    if (_buttonCilckBlock) {
        _buttonCilckBlock(CenterButtonPause);
    }
}
-(void)previousAction:(MPRemoteCommandEvent *)event{
    if (_buttonCilckBlock) {
        _buttonCilckBlock(PreviousButton);
    }
}
-(void)nextAction:(MPRemoteCommandEvent *)event{
    if (_buttonCilckBlock) {
        _buttonCilckBlock(NextButton);
    }
}
@end

调用：

    [[ControlCenter shareControlCenter]openBackstageControlAudio];
    [[ControlCenter shareControlCenter]configBackstageAudioButtons:NoneEnabled];
    [ControlCenter shareControlCenter].buttonCilckBlock = ^(BackstageButtonType type){
        switch (type) {
            case CenterButtonPlay:
                [self playOrParseMusic:YES];
                break;
            case CenterButtonPause:
                [self playOrParseMusic:NO];
                break;
            case PreviousButton:
                _playerIndex--;
                if (_playerIndex<0) {
                    _playerIndex = _playerDataArr.count-1;
                }
                [self prepareAndPlayMusic:_playerDataArr[_playerIndex]];
                break;
            case NextButton:
                _playerIndex++;
                if (_playerIndex>(_playerDataArr.count-1)) {
                    _playerIndex = 0;
                }
                [self prepareAndPlayMusic:_playerDataArr[_playerIndex]];
                break;
            default:
                break;
        }
        
    };

期待你的评论建议O(∩_∩)O~