HarmonyOS 鸿蒙Next 节拍器切换页面后，第一个声音变小，SoundPool

import Metronome from './Metronome';

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';
  private controller: TabsController = new TabsController()
  @State index: number = 0

  build() {
    Row() {
      Tabs({ barPosition: BarPosition.Start, index: this.index, controller: this.controller }) {
        TabContent() {
          Column() {
          }.backgroundColor(Color.Red)
        }.tabBar("1")

        TabContent() {
          Metronome({ currentIndex: this.index })
        }.tabBar("2")
      }.onChange((index: number) => {
        console.log(`${index}`)
        this.index = index
      })
    }
  }
}
复制
import promptAction from '@ohos.promptAction';
import { create, release, playSoundPool } from './SoundPool'

@Component
export default struct Metronome {
  @State isWorkerStart: boolean = false // 线程是否开启
  @State loopBeat: number | null = null // 闪烁延时器
  @State isTwinkleOn: boolean = true // 是否半屏闪烁
  @State isTwinkleOnText: string = '半屏闪烁' // 半屏闪烁文字
  @State beatCount: number = 4 // 节拍数
  @State beatSpeedList: string[] = this.generateBeatSpeedList() // 节拍速度数组
  @State select: number = 40 // 选中的节拍数下标
  @State selectValue: number = 80 // 选中的节拍数
  @State isPlay: boolean = false // 播放、暂停
  @State toneNum: number = 4 // 音调数
  @State isActiveBeatCount: number = 0 // 当前节拍数高亮
  @State isActiveBeatBg: boolean = false // 半屏闪烁高亮
  @State workerCode: number = 1 // 线程退出code
  @Prop @Watch('onCurrentIndexChange') currentIndex: number = 1; // tabs下标

  aboutToAppear() {
    // this.createSoundPool();
  }

  aboutToDisappear() {
    console.log('ceshiceshi')
    // this.cancelSoundPool()
    // this.cancelSoundPool().then(() => {
    //   this.cancelLoopBeatCount()
    // });
  }

  build() {
    Column() {
      // 跳转到设置
      Row() {
        Button("paly").onClick(() => {
          this.playAudio()
        })
      }
      .width('100%')
      .height('50vp')
      .justifyContent(FlexAlign.SpaceBetween)
      .alignItems(VerticalAlign.Center)
      .padding({ left: '35vp', right: '35vp' })
      .margin({ top: '15vp' })
    }
    .width('100%')
    .height('100%')
  }

  // 监听tabs下标变化
  onCurrentIndexChange() {
    console.log(this.currentIndex + 'val1133')
    if (this.currentIndex === 1) {
      this.createSoundPool();
    } else {
      console.log(`${this.currentIndex}`)
      this.cancelSoundPool()
    }
  }

  // 创建音频池
  async createSoundPool() {
    await create();
  }

  // 释放音频池
  async cancelSoundPool() {
    await release();
  }

  // 生成节拍速度数组
  generateBeatSpeedList() {
    let beatSpeedList: Array<string> = []
    for (let i = 40; i <= 218; i++) {
      beatSpeedList.push(`${i}`)
    }
    return beatSpeedList
  }

  // 播放节拍器声音
  async playAudio() {
    await playSoundPool()
  }

  // 节拍数处理
  handleTextPickerChange(value: string | string[]) {
    this.selectValue = Number(value)
  }

  // 处理是否半屏闪烁
  handleSwitchChange(isOn: boolean) {
    this.isTwinkleOn = isOn
  }

  // 动态节拍宽度
  dynamicBeatWidth(count: number) {
    let width = '20%'
    if (count == 2) {
      width = '48%'
    } else if (count == 3) {
      width = '30.6%'
    } else if (count == 4) {
      width = '22%'
    } else if (count == 5) {
      width = '16.8%'
    } else if (count == 6) {
      width = '13.3%'
    } else if (count == 7) {
      width = '10.8%'
    } else if (count == 8) {
      width = '9%'
    }
    return width
  }

  // 节拍器处理
  handleBeatCountClick() {
    if (this.isPlay) {
      promptAction.showToast({
        message: '请先暂停播放',
        duration: 2000,
        bottom: '50vp'
      });
      return
    } else {
      this.beatCount++
      if (this.beatCount > 8) {
        this.beatCount = 2
      }
    }
  }

  // 音符数处理
  handleTuneNumClick() {
    if (this.isPlay) {
      promptAction.showToast({
        message: '请先暂停播放',
        duration: 2000,
        bottom: '50vp'
      });
      return
    } else {
      this.toneNum = this.toneNum > 4 ? 1 : this.toneNum * 2;
    }
  }

  // 节拍器闪烁
  handleLoopBeatCount() {
    this.isActiveBeatBg = !this.isActiveBeatBg
  }

  // 判断节拍器半屏闪烁是否高亮
  judgeIsActiveBeatBg(idx: number) {
    if (idx === this.isActiveBeatCount) {
      return true
    } else {
      return false
    }
  }
}