Starting a Remote PageAbility (for System Applications Only)

The startAbility() method in the featureAbility class is used to start a remote PageAbility.

In addition to '@ohos.ability.featureAbility', you must import '@ohos.distributedHardware.deviceManager', which provides account-independent distributed device networking capabilities. Then you can use getTrustedDeviceListSync of the DeviceManager module to obtain the remote device ID and pass the remote device ID in the want parameter for starting the remote PageAbility.

The getTrustedDeviceListSync method is available only for system applications. Therefore, non-system applications cannot obtain remote device information or start a remote ability.

Table 1 featureAbility APIs

Table 2 deviceManager APIs

In the cross-device scenario, before starting a remote PageAbility, you must request the data synchronization permission. The related APIs are described in the table below.

Table 3 AtManager APIs

Table 4 context APIs

The following sample code shows how to request the data synchronization permission from users:

import abilityAccessCtrl from "@ohos.abilityAccessCtrl";
import featureAbility from '@ohos.ability.featureAbility';
import bundle from '@ohos.bundle.bundleManager';
async function RequestPermission() {
  console.info('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('ohos.samples.etsDemo', 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]);
    console.info("checkAccessToken result:" + JSON.stringify(result));
    if (result != abilityAccessCtrl.GrantStatus.PERMISSION_GRANTED) {
      requestPermissions.push(array[i]);
    }
  }
  console.info("requestPermissions:" + JSON.stringify(requestPermissions));
  if (requestPermissions.length == 0 || requestPermissions == []) {
    return;
  }
  let context = featureAbility.getContext();
  context.requestPermissionsFromUser(requestPermissions, 1, (error, data)=>{
    console.info("data:" + JSON.stringify(data));
    console.info("data requestCode:" + data.requestCode);
    console.info("data permissions:" + data.permissions);
    console.info("data authResults:" + data.authResults);
  });
  console.info('RequestPermission end');
}

After obtaining the data synchronization permission, obtain the trusted device list for device selection.

The following sample code shows how to use getTrustedDeviceListSync() to obtain the trusted device list.

import deviceManager from '@ohos.distributedHardware.deviceManager';

let dmClass: deviceManager.DeviceManager;

function getDeviceManager() {
  deviceManager.createDeviceManager('ohos.example.distributedService', (error, dm) => {
    if (error) {
      console.info('create device manager failed with ' + error)
    }
    dmClass = dm;
  })
}

function getRemoteDeviceId(): string | undefined {
  if (typeof dmClass === 'object' && dmClass != null) {
    let list: Array<deviceManager.DeviceInfo> = dmClass.getTrustedDeviceListSync();
    if (typeof (list) == 'undefined' || typeof (list.length) == 'undefined') {
      console.info("EntryAbility onButtonClick getRemoteDeviceId err: list is null");
      return;
    }
    console.info("EntryAbility onButtonClick getRemoteDeviceId success:" + list[0].deviceId);
    return list[0].deviceId;
  } else {
    console.info("EntryAbility onButtonClick getRemoteDeviceId err: dmClass is null");
    return;
  }
}

After a device is selected, call startAbility() to explicitly start the remote PageAbility.

The following sample code shows how to explicitly start a remote PageAbility through startAbility().

import featureAbility from '@ohos.ability.featureAbility';
import Want from '@ohos.app.ability.Want';

function onStartRemoteAbility() {
  console.info('onStartRemoteAbility begin');
  let wantValue: Want = {
    bundleName: 'ohos.samples.etsDemo',
    abilityName: 'ohos.samples.etsDemo.RemoteAbility',
    deviceId: getRemoteDeviceId(), // getRemoteDeviceId is defined in the preceding sample code.
  };
  console.info('onStartRemoteAbility want=' + JSON.stringify(wantValue));
  featureAbility.startAbility({
    want: wantValue
  }).then((data) => {
    console.info('onStartRemoteAbility finished, ' + JSON.stringify(data));
  });
  console.info('onStartRemoteAbility end');
}