HarmonyOS 鸿蒙Next系统蓝牙未开启时，是否有类似Android的系统弹窗，让用户直接打开，而不是手动

鸿蒙目前也是有类似弹窗的，在页面出现时判断当前蓝牙状态，如果是关闭，则调用打开蓝牙的方法：

1、module.json5中配置蓝牙权限：

    "requestPermissions": [
      {
        "name": "ohos.permission.ACCESS_BLUETOOTH",
        "reason": "$string:access_bluetooth_permission",
        "usedScene": {
          "abilities": [
            "EntryAbility"
          ],
          "when":"inuse"
        }
      }
]

2、Index.ets中代码：

import { access } from '@kit.ConnectivityKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { abilityAccessCtrl } from '@kit.AbilityKit';
import { promptAction } from '@kit.ArkUI';

@Entry
@Component
struct TextExample {
  @State btState:string = ''
  aboutToAppear(): void {
    // 申请蓝牙权限
    let atManager = abilityAccessCtrl.createAtManager();
    try {
      atManager.requestPermissionsFromUser(getContext(this), [
        'ohos.permission.ACCESS_BLUETOOTH'
      ])
        .then((data) => {
          console.info(`[EntryAbility], data: ${JSON.stringify(data)}`);
          this.enableBluetooth()
        })
        .catch((err: BusinessError) => {
          console.info(`[EntryAbility], err: ${JSON.stringify(err)}`);
        })
    } catch (err) {
      console.info(`[EntryAbility], catch err->${JSON.stringify(err)}`);
    }

    access.on('stateChange', (data) => {
      let btStateMessage = '';
      switch (data) {
        case 0:
          btStateMessage += 'STATE_OFF';
          this.btState = '蓝牙已关闭'
          promptAction.showToast({
            message: '蓝牙已关闭',
            duration: 2000
          });
          break;
        case 2:
          btStateMessage += 'STATE_ON';
          this.btState = '蓝牙已打开'
          promptAction.showToast({
            message: '蓝牙已打开',
            duration: 2000
          });
          break;
        default:
          btStateMessage += 'unknown status';
          break;
      }
      console.info('bluetooth statues: ' + btStateMessage);
    })
  }

  onPageShow(): void {
    this.enableBluetooth()
  }

  //判断当前蓝牙状态，如果是关闭，则调用打开蓝牙的方法
  enableBluetooth(){
    try {
      let state = access.getState();
      if(state===0){
        access.enableBluetooth();
      }
    } catch (err) {
      console.error('errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
    }
  }

  build() {
    Row() {
      Column({space:20}) {
        Text('测试:'+this.btState).fontSize(20)
        Button('关闭蓝牙').onClick(()=>{
          access.disableBluetooth()
        })
      }
      .width('100%')
    }
    .height('100%')
  }
}