双非大学生自学鸿蒙5.0零基础入门到项目实战--黑马云音乐下篇

import { avSession } from '@kit.AVSessionKit'
import { wantAgent } from '@kit.AbilityKit';
import backgroundTaskManager from '@ohos.resourceschedule.backgroundTaskManager';
import { GlobalMusic } from '../models/globalMusic';
import { AppStorageV2 } from '@kit.ArkUI';
import { SongItemType } from '../models/music';
import { playerManager } from './AvPlayerManager';

class AvSessionManager{
  session : avSession.AVSession | null = null
  playState:GlobalMusic = AppStorageV2.connect(GlobalMusic,'SONG_KEY',()=>new GlobalMusic())!


  async init(content:Context){
    this.session = await avSession.createAVSession(content,'bgPlay','audio')
    this.registerEvent()
  }

  // 申请长时任务
  async startBackGroundTask(){
    let wantAgentInfo: wantAgent.WantAgentInfo = {
      wants: [
        {
          bundleName: "com.example.von_music",
          abilityName: "EntryAbility"
        }
      ],
      actionType: wantAgent.OperationType.START_ABILITY,
      requestCode: 0,
      actionFlags: [wantAgent.WantAgentFlags.UPDATE_PRESENT_FLAG],
    };
    const want = await wantAgent.getWantAgent(wantAgentInfo)
    await backgroundTaskManager.startBackgroundRunning(getContext(),backgroundTaskManager.BackgroundMode.AUDIO_PLAYBACK,want)
  }

  // 设置元数据
  setAVMetadata(song:SongItemType){
    this.session?.setAVMetadata({
      assetId:song.id,
      title:song.name,
      mediaImage:song.img,
      artist:song.author,
      duration:this.playState.duration
    })
  }

  // 设置播放状态
  setAVPlayBackState(){
    this.session?.setAVPlaybackState({
      state:this.playState.isPlay ? avSession.PlaybackState.PLAYBACK_STATE_PLAY : avSession.PlaybackState.PLAYBACK_STATE_PAUSE,
      speed:1,
      position:{
        elapsedTime:this.playState.time,//歌曲播放时间
        updateTime:new Date().getTime()//系统时间
      },
      duration:this.playState.duration
    })
  }

  // 注册事件
  registerEvent(){
    this.session?.on('play',()=>{
      playerManager.singPlay(this.playState.playList[this.playState.playIndex])
    })
    this.session?.on('pause',()=>{
      playerManager.paused()
    })
    this.session?.on('playPrevious',()=>{
      playerManager.prevPlay()
    })
    this.session?.on('playNext',()=>{
      playerManager.nextPlay()
    })
    this.session?.on('seek',(value:number)=>{
      playerManager.seekPlay(value)
    })
    this.session?.activate()
  }

  // 注销会话
  async destroy(){
    await this.session?.destroy()
  }

}

export const sessionManager : AvSessionManager = new AvSessionManager()

import { media } from '@kit.MediaKit'
import { GlobalMusic } from '../models/globalMusic'
import { SongItemType } from '../models/music'
import { AppStorageV2 } from '@kit.ArkUI'
import { sessionManager } from './AvSessionManager'

class AvPlayerManager{
  // 播放器
  player : media.AVPlayer | null = null
  currentSong : GlobalMusic = AppStorageV2.connect(GlobalMusic,'SONG_KEY',()=>new GlobalMusic())!

  // 定义方法
  async init () {
    if(!this.player){
      this.player = await media.createAVPlayer()
    }
    // 监听状态变化
    this.player.on('stateChange',(state) => {
      if(state === 'initialized'){
        this.player?.prepare()
      }else if(state === 'prepared'){
        this.player?.play()
        this.currentSong.isPlay = true
      } else if(state === 'completed'){
        this.nextPlay(true)
      } else if(state === 'released'){
        this.currentSong.reset()
      }
    })

    // 监听时间变化
    this.player.on('durationUpdate',(duration)=>{
      this.currentSong.duration = duration
      sessionManager.setAVMetadata((this.currentSong.playList[this.currentSong.playIndex]))
    })
    this.player.on('timeUpdate',(time)=>{
      this.currentSong.time = time
      sessionManager.setAVPlayBackState()
    })

  }

  // 播放歌曲
  singPlay(song:SongItemType){
    // 申请长时任务
    sessionManager.startBackGroundTask()
    sessionManager.setAVPlayBackState()
    const inList = this.currentSong.playList.some(item => item.id === song.id)
    // 歌曲在列表里
    if(inList){
      // 正在播放
      if(this.currentSong.url === song.url){
        this.player?.play()
        this.currentSong.isPlay = true
      }else {
        // 如果没有播放根据索引找到歌曲进行播放
        this.currentSong.playIndex = this.currentSong.playList.findIndex(item => item.id === song.id)

        // 切歌
        this.changeSong()
      }
    } else { // 歌曲不在列表
      this.currentSong.playList.unshift(song) // 将歌曲添加到列表并且设置为索引为0
      this.currentSong.playIndex = 0
      // 切歌
      this.changeSong()
    }
  }

  // 切歌
  async changeSong() {
    await this.player?.reset()
    this.currentSong.duration = 0
    this.currentSong.time = 0
    this.currentSong.img = this.currentSong.playList[this.currentSong.playIndex].img
    this.currentSong.name = this.currentSong.playList[this.currentSong.playIndex].name
    this.currentSong.author = this.currentSong.playList[this.currentSong.playIndex].author
    this.currentSong.url = this.currentSong.playList[this.currentSong.playIndex].url
    this.player!.url = this.currentSong.url
  }

  // 跳转进度 seek
  seekPlay(value:number){
    this.player?.seek(value)
  }

  // 暂停
  paused() {
    this.player?.pause()
    this.currentSong.isPlay = false
    sessionManager.setAVPlayBackState()

  }

  // 上一首
  prevPlay(){
    if(this.currentSong.playMode === 'random'){
      // 随机播放
      // Math.random : [0,1)
      this.currentSong.playIndex = Math.floor(Math.random() * this.currentSong.playList.length)
    }else {
      this.currentSong.playIndex--
      if(this.currentSong.playIndex < 0){
        this.currentSong.playIndex = this.currentSong.playList.length - 1
      }
    }
    this.singPlay(this.currentSong.playList[this.currentSong.playIndex])
  }

  // 下一首
  nextPlay(autoNextPlay ?: boolean){
    if(this.currentSong.playMode === 'repeat' && autoNextPlay){// 重复播放：当前模式为repeat并且autoNextPlay为true
      this.currentSong.playIndex = this.currentSong.playIndex
    }else if(this.currentSong.playMode === 'random'){
      // 随机播放
      // Math.random : [0,1)
      this.currentSong.playIndex = Math.floor(Math.random() * this.currentSong.playList.length)
    } else {
      this.currentSong.playIndex++
      if(this.currentSong.playIndex >=  this.currentSong.playList.length){
        this.currentSong.playIndex = 0
      }
    }
    this.singPlay(this.currentSong.playList[this.currentSong.playIndex])
  }

  // 列表移除歌曲
  removeSong(index:number){
    if(index === this.currentSong.playIndex){
      // 删除的是正在播放的歌曲
      if(this.currentSong.playList.length > 1){
        // 列表有多首歌
        this.currentSong.playList.splice(index,1)
        // 目前播放的歌曲的最后一首
        if(this.currentSong.playIndex >= this.currentSong.playList.length){
          this.currentSong.playIndex = 0
        }
        this.singPlay(this.currentSong.playList[this.currentSong.playIndex])
      }else{
        // 列表只有一首歌
        this.player?.reset()
        this.currentSong.reset()
      }
    } else {
      if(index < this.currentSong.playIndex){
        // 要删除歌曲在播放的前面
        this.currentSong.playIndex--
      }
      this.currentSong.playList.splice(index,1)
    }
  }

  // 释放播放器
  async release() {
    await this.player?.release()
  }
}

export const playerManager : AvPlayerManager = new AvPlayerManager()