目录

UIAbility组件基本用法

本文主要介绍UIAbility组件的基本用法,包括:

指定UIAbility的启动页面

应用中的UIAbility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()生命周期回调中,通过WindowStage对象的loadContent()方法设置启动页面。

import { AbilityConstant, UIAbility, Want } 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) => {
      // ···
    });
  }

// ···
}

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类拥有自身的上下文信息,该信息为UIAbilityContext类的实例,UIAbilityContext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()、connectServiceExtensionAbility()、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()方法获取UIContext对象,再调用UIContext对象的getHostContext()方法获取当前页面关联的UIAbilityContext或ExtensionContext。

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@ohos.app.ability.Want中parameters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。

    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()生命周期中,获取UIAbilityA的Pid、BundleName和AbilityName,并通过日志输出。

    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.`);
        });
      }
    }