本文主要介绍UIAbility组件的基本用法,包括:
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。
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。
在UIAbility中可以通过this.context获取UIAbility实例的上下文信息。
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。
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前进行变量定义。
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实例,可以通过调用terminateSelf()方法实现。
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 ${message}.`);
}
})
// ...
}
// ...
}
} 拉起方(UIAbilityA)通过startAbility启动目标方(UIAbilityB)时,UIAbilityB可以通过@ohos.app.ability.Want中parameters参数获取UIAbilityA的Pid、BundleName和AbilityName等信息。
通过点击UIAbilityA中的"拉起UIAbilityB"按钮,拉起UIAbilityB。
import { common, Want } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';
@Entry
@Component
struct Index {
@State context: common.UIAbilityContext = this.getUIContext().getHostContext() as common.UIAbilityContext;
build() {
List({ space: 4 }) {
ListItem() {
Button('terminateSelf').onClick(() => {
this.context.terminateSelf()
})
.width('100%')
}
ListItem() {
// 请将$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})
}
} 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.`);
});
}
}