PageAbility开发指导

概述

功能简介

PageAbility是具备ArkUI实现的Ability，是开发者具体可见并可以交互的Ability实例。开发者通过IDE创建Ability时，IDE会自动创建相关模板代码。PageAbility相关能力通过单独的featureAbility实现，生命周期相关回调则通过app.js/app.ets中各个回调函数实现。

PageAbility的生命周期

PageAbility生命周期介绍（Ability Life Cycle）：

PageAbility生命周期是PageAbility被调度到INACTIVE、ACTIVE、BACKGROUND等各个状态的统称。

PageAbility生命周期流转如下图所示：

Ability生命周期状态说明：

• UNINITIALIZED：未初始状态，为临时状态，PageAbility被创建后会由UNINITIALIZED状态进入INITIAL状态。

• INITIAL：初始化状态，也表示停止状态，表示当前PageAbility未运行，PageAbility被启动后由INITIAL态进入INACTIVE状态。

• INACTIVE：失去焦点状态，表示当前窗口已显示但是无焦点状态。

• ACTIVE：前台激活状态，表示当前窗口已显示，并获取焦点。

• BACKGROUND：后台状态，表示当前PageAbility退到后台，PageAbility在被销毁后由BACKGROUND状态进入INITIAL状态，或者重新被激活后由BACKGROUND状态进入ACTIVE状态。

PageAbility生命周期回调与生命周期状态的关系如下图所示：

PageAbility提供生命周期回调，开发者可以在app.js/app.ets中重写生命周期相关回调函数 。目前app.js环境中仅支持onCreate和onDestroy回调，app.ets环境支持全量生命周期回调。

启动模式

ability支持单实例和多实例两种启动模式。 在config.json中通过launchType配置项，可以配置具体的启动模式，其中：

缺省情况下是singleton模式。

开发指导

featureAbility接口说明

表1 featureAbility接口介绍

启动本地PageAbility

导入模块

  import featureAbility from '@ohos.ability.featureAbility'

示例

  import featureAbility from '@ohos.ability.featureAbility'
  featureAbility.startAbility({
  want:
  {
    action: "",
    entities: [""],
    type: "",
    options: {
      // Grant the permission to perform read operations on the URI.
      authReadUriPermission: true,
      // Grant the permission to perform write operations on the URI.
      authWriteUriPermission: true,
      // support forwarding the Want result to the ability.
      abilityForwardResult: true,
      // Enable abiligy continuation.
      abilityContinuation: true,
      // Specify that a component does not belong to ohos.
      notOhosComponent: true,
      // Specify that an ability is started.
      abilityFormEnabled: true,
      // Grant the permission for possible persisting on the URI.
      authPersistableUriPermission: true,
      // Grant the permission for possible persisting on the prefix URI.
      authPrefixUriPermission: true,
      // Support distributed scheduling system startup on multiple devices.
      abilitySliceMultiDevice: true,
      // A service ability is started regardless of whether the host application has been started.
      startForegroundAbility: true,
      // Install the specified ability if it is not installed.
      installOnDemand: true,
      // Return the result to the ability slice.
      abilitySliceForwardResult: true,
      // Install the specified ability with background mode if it is not installed.
      installWithBackgroundMode: true
    },
    deviceId: "",
    bundleName: "com.example.startability",
    abilityName: "com.example.startability.MainAbility",
    uri: ""
  },
  },
  );

want参数也可以使用parameters参数，使用key-value的方式输入。

示例

  import featureAbility from '@ohos.ability.featureAbility'
  featureAbility.startAbility({
    want:
    {
        bundleName: "com.example.startability",
        uri: "",
        parameters: {
            abilityName: "com.example.startability.MainAbility"
        }
    },
  },
  );

启动远程PageAbility（当前仅对系统应用开放）

说明：由于DeviceManager的getTrustedDeviceListSync接口仅对系统应用开放，当前启动远程PageAbility仅支持系统应用

导入模块

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

示例

  function onStartRemoteAbility() {
  console.info('onStartRemoteAbility begin');
  let params;
  let wantValue = {
    bundleName: 'ohos.samples.etsDemo',
    abilityName: 'ohos.samples.etsDemo.RemoteAbility',
    deviceId: getRemoteDeviceId(),
    parameters: params
  };
  console.info('onStartRemoteAbility want=' + JSON.stringify(wantValue));
  featureAbility.startAbility({
    want: wantValue
  }).then((data) => {
    console.info('onStartRemoteAbility finished, ' + JSON.stringify(data));
  });
  console.info('onStartRemoteAbility end');
  }

从DeviceManager获取deviceId，具体示例代码如下：

  import deviceManager from '@ohos.distributedHardware.deviceManager';
  let dmClass;
  function getRemoteDeviceId() {
    if (typeof dmClass === 'object' && dmClass != null) {
        let list = dmClass.getTrustedDeviceListSync();
        if (typeof (list) == 'undefined' || typeof (list.length) == 'undefined') {
            console.log("MainAbility onButtonClick getRemoteDeviceId err: list is null");
            return;
        }
        console.log("MainAbility onButtonClick getRemoteDeviceId success:" + list[0].deviceId);
        return list[0].deviceId;
    } else {
        console.log("MainAbility onButtonClick getRemoteDeviceId err: dmClass is null");
    }
  }

在跨设备场景下，需要向用户申请数据同步的权限。具体示例代码如下：

  import abilityAccessCtrl from "@ohos.abilityAccessCtrl";
  import bundle from '@ohos.bundle';
  async function RequestPermission() {
  console.info('RequestPermission begin');
  let array: Array<string> = ["ohos.permission.DISTRIBUTED_DATASYNC"];
  let bundleFlag = 0;
  let tokenID = 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("verifyAccessToken result:" + JSON.stringify(result));
    if (result == abilityAccessCtrl.GrantStatus.PERMISSION_GRANTED) {
    } else {
      requestPermissions.push(array[i]);
    }
  }
  console.info("requestPermissions:" + JSON.stringify(requestPermissions));
  if (requestPermissions.length == 0 || requestPermissions == []) {
    return;
  }
  let context = featureAbility.getContext();
  context.requestPermissionsFromUser(requestPermissions, 1, (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');
  }

生命周期接口说明

表2 生命周期回调函数介绍

示例

开发者需要重写app.js/app.ets中相关生命周期回调函数，IDE模板默认生成onCreate()和onDestroy()方法，其他方法需要开发者自行实现。

export default {
  onCreate() {
    console.info('Application onCreate')
  },
  onDestroy() {
    console.info('Application onDestroy')
  },
  onShow(){
    console.info('Application onShow')
  },
  onHide(){
    console.info('Application onHide')
  },
  onInactive(){
    console.info('Application onInactive')
  },
  onActive(){
    console.info('Application onActive')
  },
}

相关实例

针对PageAbility开发，有以下相关实例可供参考：

• DMS：分布式Demo（eTS）（API8）（Full SDK）