# PageAbility开发说明

## PageAbility介绍

Page模板（以下简称“Page”）是FA唯一支持的模板，用于提供与用户交互的能力。

## PageAbility的生命周期

**Ability生命周期介绍**（Ability Life Cycle）是Ability被调度到INACTIVE、ACTIVE、BACKGROUND等各个状态的统称（主要涉及PageAbility类型和ServiceAbility类型的Ability）。

  - **PageAbility类型的Ability生命周期流转如下图所示**

![PageAbility-Lifecycle](figures/page-ability-lifecycle.png)


**Ability生命周期状态说明：**

  - **UNINITIALIZED**：未初始状态，为临时状态，Ability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Ability未运行，Ability被启动后由INITIAL态进入INACTIVE状态。

  - **INACTIVE**：未激活状态，表示当前窗口已显示但是无焦点状态，由于Window暂未支持焦点的概念，当前状态与ACTIVE一致。

  - **ACTIVE**：前台激活状态，表示当前窗口已显示，并获取焦点，Ability在退到后台之前先由ACTIVE状态进入INACTIVE状态。

  - **BACKGROUND**: 后台状态，表示当前Ability退到后台，Ability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类型Ability生命周期回调如下图所示：**

![PageAbility-Lifecycel-Callbacks](figures/page-ability-lifecycle-callbacks.png)

  

## 启动本地PageAbility

 导入模块

```
import featureAbility from '@ohos.ability.featureAbility'
```
```
 FeatureAbility.startAbility(parameter: StartAbilityParameter, callback: AsyncCallback<number>)
```

* 接口说明

  启动新的ability(callback形式)

* 示例

```javascript
import featureAbility from '@ohos.ability.featureAbility'
featureAbility.startAbility(
        {
        want:
        {
            action: "",
            entities: [""],
            type: "",
            options: {
                // indicates the grant to perform read operations on the URI
                authReadUriPermission: true,
                // indicates the grant to perform write operations on the URI
                authWriteUriPermission: true,
                // support forward intent result to origin ability
                abilityForwardResult: true,
                // used for marking the ability start-up is triggered by continuation
                abilityContinuation: true,
                // specifies whether a component does not belong to ohos
                notOhosComponent: true,
                // specifies whether an ability is started
                abilityFormEnabled: true,
                // indicates the grant for possible persisting on the URI.
                authPersistableUriPermission: true,
                // indicates the grant for possible persisting on the URI.
                authPrefixUriPermission: true,
                // support distributed scheduling system start up multiple devices
                abilitySliceMultiDevice: true,
                // indicates that an ability using the service template is started regardless of whether the
                // host application has been started.
                startForegroundAbility: true,
                // install the specified ability if it's not installed.
                installOnDemand: true,
                // return result to origin ability slice
                abilitySliceForwardResult: true,
                // install the specified ability with background mode if it's not installed.
                installWithBackgroundMode: true
            },
            deviceId: "",
            bundleName: "com.example.startability",
            abilityName: "com.example.startability.MainAbility",
            uri: ""
        },
    },
  );
)
```
## 启动远程PageAbility

 导入模块

```
import featureAbility from '@ohos.ability.featureAbility'
```

```
FeatureAbility.startAbility(parameter: StartAbilityParameter)
```
* 接口说明

  启动远程的ability(promise形式)
  前提：通过deviceManager获取远程deviceid

* 示例

```javascript
        var promise = await ability.startAbility(
            {
                want:
                {
                    deviceId: this.deviceId,
                    bundleName: "com.example.test",
                    abilityName: "com.example.test.MainAbility",
                },
            }
        );
```