好几天米撸了，今天撸篇..音乐后台播放操作及显示封面

按步骤，今天的主题主要是实现后台播放及显示，其他播放音乐步骤略过...

锁屏

上拉

第一步：Info.plist

Info.plist

方便大家复制：上代码

            Required background modes  | App plays audio or streams audio/video using AirPlay

第二步：AppDelegate.swift

      /**注意：记得先在头部写上 import AVFoundation */
    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // 注册后台播放
        let session = AVAudioSession.sharedInstance()
        do {
            try session.setActive(true)
            try session.setCategory(AVAudioSessionCategoryPlayback)
        } catch {
            print(error)
        }
        return true
    }

第三步：ViewController.swift

import AVFoundation

class ViewController: UIViewController {

    var audioPlayer = AVAudioPlayer()
    
    override func viewDidLoad() {
        super.viewDidLoad()

        //1.告诉系统接受远程响应事件，并注册成为第一响应者
        UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
        self.becomeFirstResponder()
    }
    
    override func viewWillDisappear(animated: Bool) {
        UIApplication.sharedApplication().endReceivingRemoteControlEvents()
        self.resignFirstResponder()
    }
    
    override func canBecomeFirstResponder() -> Bool {
        return true
    }
    /*                                                                           
      *   加载音乐文件略 ，定时器定时更新后台信息略....
      *    audioPlayer = try! AVAudioPlayer... //加载
     *     audioPlayer.paly() //播放  audioPlayer.stop() //暂停 
      *    audioPlayer.currentTime //可以更改播放进度
      *    以后有空再来一波
    */
  }


  // MARK: - 设置后台播放显示信息
extension ViewController {
    
    func setBackground() {
        //大标题 - 小标题  - 歌曲总时长 - 歌曲当前播放时长 - 封面
        let settings = [MPMediaItemPropertyTitle: "大标题",
                        MPMediaItemPropertyArtist: "小标题",
                        MPMediaItemPropertyPlaybackDuration: "\(audioPlayer.duration)",
                        MPNowPlayingInfoPropertyElapsedPlaybackTime: "\(audioPlayer.currentTime)",
                        MPMediaItemPropertyArtwork: MPMediaItemArtwork(image: UIImage(named: " cover")!)]

         MPNowPlayingInfoCenter.defaultCenter().setValue(settings, forKey: "nowPlayingInfo")
      }
}


// MARK: - 后台操作
extension ViewController {
    override func remoteControlReceivedWithEvent(event: UIEvent?) {
         
        if event?.type == UIEventType.RemoteControl {
            switch event!.subtype {
            case .RemoteControlTogglePlayPause:
                print("暂停/播放")
            case .RemoteControlPreviousTrack: // ##  <-  ##
                print("上一首")
            case .RemoteControlNextTrack: // ## -> ##
                print("下一首")
            case .RemoteControlPlay: // ## > ##
                print(">")
            case .RemoteControlPause: // ## || ##
                print("||")
            default:
                break
            }
        }
    }
}