# UIAbility组件基本用法 本文主要介绍[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)组件的基本用法，包括： - 指定UIAbility的启动页面。 - 获取UIAbility的上下文[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)。 - 获取UIAbility拉起方的信息。 ## 指定UIAbility的启动页面 应用中的[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)在启动过程中，需要指定启动页面，否则应用启动后会因为没有默认加载页面而导致白屏。可以在UIAbility的[onWindowStageCreate()](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md#onwindowstagecreate)生命周期回调中，通过[WindowStage](../reference/apis-arkui/arkts-apis-window-WindowStage.md)对象的[loadContent()](../reference/apis-arkui/arkts-apis-window-WindowStage.md#loadcontent9)方法设置启动页面。 ``` TypeScript import { UIAbility } from '@kit.AbilityKit'; import { window } from '@kit.ArkUI'; // ··· export default class EntryAbility extends UIAbility { // ··· onWindowStageCreate(windowStage: window.WindowStage): void { // Main window is created, set main page for this ability windowStage.loadContent('pages/Index', (err) => { // ··· }); } // ··· } ``` > **说明：** > 在DevEco Studio中创建的UIAbility中，该UIAbility实例默认会加载Index页面，根据需要将Index页面路径替换为需要的页面路径即可。 ## 获取UIAbility的上下文信息 [UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)类拥有自身的上下文信息，该信息为[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)类的实例，[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)类拥有abilityInfo、currentHapModuleInfo等属性。通过UIAbilityContext可以获取UIAbility的相关配置信息，如包代码路径、Bundle名称、Ability名称和应用程序需要的环境状态等属性信息，以及可以获取操作UIAbility实例的方法（如[startAbility()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#startability)、[connectServiceExtensionAbility()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#connectserviceextensionability)、[terminateSelf()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#terminateself)等）。 如果需要在页面中获得当前Ability的Context，需要通过调用组件的[getUIContext](../reference/apis-arkui/arkui-ts/ts-custom-component-api.md#getuicontext)方法获取[UIContext](../reference/apis-arkui/arkts-apis-uicontext-uicontext.md)对象，再调用UIContext对象的[getHostContext](../reference/apis-arkui/arkts-apis-uicontext-uicontext.md#gethostcontext12)方法获取当前页面关联的UIAbilityContext或[ExtensionContext](../reference/apis-ability-kit/js-apis-inner-application-extensionContext.md)。 - 在UIAbility中可以通过`this.context`获取UIAbility实例的上下文信息。 ``` TypeScript import { AbilityConstant, UIAbility, Want } from '@kit.AbilityKit'; // ··· export default class EntryAbility extends UIAbility { onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void { // 获取UIAbility实例的上下文 let context = this.context; } // ··· } ``` - 在页面中获取UIAbility实例的上下文信息，包括导入依赖资源context模块和在组件中定义一个context变量两个部分。 ``` TypeScript import { common, Want } from '@kit.AbilityKit'; @Entry @Component struct EventHubPage { private context = this.getUIContext().getHostContext() as common.UIAbilityContext; startAbilityTest(): void { let want: Want = { // Want参数信息 // ... }; this.context.startAbility(want); } // 页面展示 build() { // ... } } ``` 也可以在导入依赖资源context模块后，在具体使用[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)前进行变量定义。 ``` TypeScript import { common, Want } from '@kit.AbilityKit'; // ... @Entry @Component struct BasicUsage { startAbilityTest(): void { let context = this.getUIContext().getHostContext() as common.UIAbilityContext; let want: Want = { // Want参数信息 // ... }; context.startAbility(want); } // 页面展示 build() { // ... } } ``` - 当业务完成后，开发者如果想要终止当前[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)实例，可以通过调用[terminateSelf()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#terminateself)方法实现。 ``` TypeScript import { common, Want } from '@kit.AbilityKit'; import { BusinessError } from '@kit.BasicServicesKit'; import { hilog } from '@kit.PerformanceAnalysisKit'; const DOMAIN = 0x0000; @Entry @Component struct BasicUsage { // ... // 页面展示 build() { Column() { // ... Button('FuncAbilityB') .onClick(() => { let context = this.getUIContext().getHostContext() as common.UIAbilityContext; try { context.terminateSelf((err: BusinessError) => { if (err.code) { // 处理业务逻辑错误 hilog.error(DOMAIN, 'terminateSelf', `terminateSelf failed, code is ${err.code}, message is ${err.message}.`); return; } // 执行正常业务 hilog.info(DOMAIN, 'terminateSelf', `terminateSelf succeed.`); }); } catch (err) { // 捕获同步的参数错误 let code = (err as BusinessError).code; let message = (err as BusinessError).message; hilog.error(DOMAIN, 'terminateSelf', `terminateSelf failed, code is ${code}, message is ${message}.`); } }) // ... } // ... } } ``` ## 获取UIAbility拉起方的信息 拉起方（UIAbilityA）通过startAbility启动目标方（UIAbilityB）时，UIAbilityB可以通过[parameters](../reference/apis-ability-kit/js-apis-app-ability-want.md)参数获取UIAbilityA的Pid、BundleName和AbilityName等信息。 1. 通过点击UIAbilityA中的"拉起UIAbilityB"按钮，拉起UIAbilityB。 ``` TypeScript import { common, Want } from '@kit.AbilityKit'; import { BusinessError } from '@kit.BasicServicesKit'; @Entry @Component struct Index { @State context: common.UIAbilityContext = this.getUIContext().getHostContext() as common.UIAbilityContext; build() { List({ space: 4 }) { ListItem() { Button('terminateSelf').onClick(() => { this.context.terminateSelf() }) .width('100%') } ListItem() { // 请将$r('app.string.Start_UIAbilityB')替换为实际资源文件，在本示例中该资源文件的value值为"拉起UIAbilityB" Button($r('app.string.Start_UIAbilityB')) .onClick((event: ClickEvent) => { let want: Want = { bundleName: this.context.abilityInfo.bundleName, abilityName: 'UIAbilityB', }; this.context.startAbility(want, (err: BusinessError) => { if (err.code) { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}.`); } }); }) .width('100%') } } .listDirection(Axis.Vertical) .backgroundColor(0xDCDCDC).padding(20) .margin({top:250}) } } ``` 2. 在UIAbilityB的[onCreate](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md#oncreate)生命周期中，获取UIAbilityA的Pid、BundleName和AbilityName，并通过日志输出。 ``` TypeScript import { AbilityConstant, UIAbility, Want } from '@kit.AbilityKit'; import { window } from '@kit.ArkUI'; import { hilog } from '@kit.PerformanceAnalysisKit'; const DOMAIN = 0x0000; export default class UIAbilityB extends UIAbility { onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void { // 调用方无需手动传递parameters参数，系统会自动向Want对象中传递调用方信息。 hilog.info(DOMAIN, 'UIAbilityB', `onCreate, callerPid: ${want.parameters?.['ohos.aafwk.param.callerPid']}.`); hilog.info(DOMAIN, 'UIAbilityB', `onCreate, callerBundleName: ${want.parameters?.['ohos.aafwk.param.callerBundleName']}.`); hilog.info(DOMAIN, 'UIAbilityB', `onCreate, callerAbilityName: ${want.parameters?.['ohos.aafwk.param.callerAbilityName']}.`); } onDestroy(): void { hilog.info(DOMAIN, 'UIAbilityB', `UIAbilityB onDestroy.`); } onWindowStageCreate(windowStage: window.WindowStage): void { hilog.info(DOMAIN, 'UIAbilityB', `Ability onWindowStageCreate.`); windowStage.loadContent('context/BasicUsage', (err) => { if (err.code) { hilog.error(DOMAIN, 'UIAbilityB', `Failed to load the content, error code: ${err.code}, error msg: ${err.message}.`); return; } hilog.info(DOMAIN, 'UIAbilityB', `Succeeded in loading the content.`); }); } } ```