启动远程PageAbility（仅对系统应用开放）

启动远程PageAbility同样通过featureAbility中的startAbility接口实现。

除引入'@ohos.ability.featureAbility'外，还需引入'@ohos.distributedHardware.deviceManager'，通过DeviceManager（该组件提供帐号无关的分布式设备的认证组网能力）的getTrustedDeviceListSync接口（获取信任设备列表）获取远端的deviceId，写入want中，用于启动远程PageAbility。

由于当前DeviceManager的getTrustedDeviceListSync接口仅对系统应用开放，故现阶段非系统应用无法获取其他设备信息，无远程启动设备选择入口，远程启动Ability开发。

表1 featureAbility接口说明

表2 deviceManager接口说明

在跨设备场景下，启动远程PageAbility首先需要向用户申请数据同步的权限，相关接口说明如下：

表3 AtManager接口说明

表4 context接口说明

如下示例代码展示了向用户申请数据同步权限的方法：

import abilityAccessCtrl from "@ohos.abilityAccessCtrl";
import featureAbility from '@ohos.ability.featureAbility';
import bundle from '@ohos.bundle.bundleManager';
import Logger from '../../utils/Logger';

const TAG: string = 'PagePageAbilitySecond';

async requestPermission(): Promise<void> {
  Logger.info(TAG, 'RequestPermission begin');
  let array: Array<string> = ['ohos.permission.DISTRIBUTED_DATASYNC'];
  let bundleFlag = 0;
  let tokenID: number | undefined = undefined;
  let userID = 100;
  let appInfo = await bundle.getApplicationInfo('com.samples.famodelabilitydevelop', bundleFlag, userID);
  tokenID = appInfo.accessTokenId;
  let atManager = abilityAccessCtrl.createAtManager();
  let requestPermissions: Array<string> = [];
  for (let i = 0;i < array.length; i++) {
    let result = await atManager.verifyAccessToken(tokenID, array[i]);
    Logger.info(TAG, 'checkAccessToken result:' + JSON.stringify(result));
    if (result != abilityAccessCtrl.GrantStatus.PERMISSION_GRANTED) {
      requestPermissions.push(array[i]);
    }
  }
  Logger.info(TAG, 'requestPermissions:' + JSON.stringify(requestPermissions));
  if (requestPermissions.length == 0) {
    return;
  }
  let context = featureAbility.getContext();
  context.requestPermissionsFromUser(requestPermissions, 1, (error, data) => {
    Logger.info(TAG, 'error:' + error.message + ',data:' + JSON.stringify(data));
    Logger.info(TAG, 'data requestCode:' + data.requestCode);
    Logger.info(TAG, 'data permissions:' + data.permissions);
    Logger.info(TAG, 'data authResults:' + data.authResults);
  });
  Logger.info(TAG, 'RequestPermission end');
}

在获取数据同步权限后，需要获取可信设备列表，进行设备选择。

如下示例展示了通过getAvailableDeviceListSync获取可信设备列表，选择设备的方法。

import deviceManager from '@ohos.distributedDeviceManager';
import promptAction from '@ohos.promptAction';
import Logger from '../../utils/Logger';

const TAG: string = 'PagePageAbilitySecond';

@State deviceID: string = '';

getRemoteDeviceId(): void {
  let dmClass: deviceManager.DeviceManager;
  dmClass = deviceManager.createDeviceManager('com.samples.famodelabilitydevelop');
  try {
    if (typeof dmClass === 'object' && dmClass !== null) {
      let list = dmClass.getAvailableDeviceListSync();
      if (typeof (list) == undefined || list.length == 0) {
        Logger.info(TAG, 'EntryAbility onButtonClick getRemoteDeviceId err: list is null');
        return;
      }
      Logger.info(TAG, `EntryAbility onButtonClick getRemoteDeviceId success[${list.length}]:` + JSON.stringify(list[0]));
      if (list[0].networkId != undefined) {
        this.deviceID = list[0].networkId;
      }
      promptAction.showToast({
        message: this.deviceID
      });
    } else {
      Logger.info(TAG, 'EntryAbility onButtonClick getRemoteDeviceId err: dmClass is null');
    }
  } catch (error) {
    Logger.info(TAG, `getRemoteDeviceId error, error=${error}, message=${error.message}`);
  }
}

设备选择完成后，通过调用startAbility接口，显式启动远程PageAbility。

如下示例展示了通过startAbility显式启动远程PageAbility的方法。

import featureAbility from '@ohos.ability.featureAbility';
import Want from '@ohos.app.ability.Want';
import promptAction from '@ohos.promptAction';
import { BusinessError } from '@ohos.base';
import Logger from '../../utils/Logger';

const TAG: string = 'PagePageAbilitySecond';;

@State deviceID: string = '';

onStartRemoteAbility(): void {
  Logger.info(TAG, 'onStartRemoteAbility begin');
  let wantValue: Want = {
    bundleName: 'ohos.samples.distributedmusicplayer',
    abilityName: 'ohos.samples.distributedmusicplayer.MainAbility',
    deviceId: this.deviceID, // this.deviceID的获取方式在前面的示例代码中
  };
  Logger.info(TAG, 'onStartRemoteAbility want=' + JSON.stringify(wantValue));
  featureAbility.startAbility({
    want: wantValue
  }).then((data) => {
    promptAction.showToast({
      message: $r('app.string.start_remote_success_toast')
    });
    Logger.info(TAG, 'onStartRemoteAbility finished, ' + JSON.stringify(data));
  }).catch((error: BusinessError) => {
    promptAction.showToast({
      message: JSON.stringify(error)
    });
    Logger.error(TAG, 'onStartRemoteAbility failed: ' + JSON.stringify(error));
  });
  Logger.info(TAG, 'onStartRemoteAbility end');
}