ios app退到播放器退到后台，MPNowPlayingIn

        NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
        //设置歌曲题目
        NSString*titleStr = self.vod.title;
        if (titleStr != nil && titleStr.length != 0) {
            [dict setObject:titleStr forKey:MPMediaItemPropertyTitle];
        }
        //设置歌手名
        [dict setObject:@"" forKey:MPMediaItemPropertyArtist];
        //设置专辑名
        [dict setObject:@"" forKey:MPMediaItemPropertyAlbumTitle];
        //设置显示的图片
        UIImage *newImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:self.vod.imageUrl]]];
        #####//其中设置图片这一块有改动
        ##### //老的代码
//        [dict setObject:[[MPMediaItemArtwork alloc] initWithImage:newImage] forKey:MPMediaItemPropertyArtwork];
   
       #####//新的代码
       #####//CGSizeMake(100, 200) 大小自定义
        [dict setObject:[[MPMediaItemArtwork alloc] initWithBoundsSize:CGSizeMake(100, 200) requestHandler:^UIImage * _Nonnull(CGSize size) {
            return newImage;
        }] forKey:MPMediaItemPropertyArtwork];

        //更新字典
        [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:dict];