harmony 鸿蒙@ohos.app.ability.Want (Want)
@ohos.app.ability.Want (Want)
Want是对象间信息传递的载体,可以用于应用组件间的信息传递。Want的使用场景之一是作为startAbility的参数,其包含了指定的启动目标,以及启动时需携带的相关数据,例如bundleName和abilityName字段分别指明目标Ability所在应用的包名以及对应包内的Ability名称。当UIAbilityA需要启动UIAbilityB并传入一些数据时,可使用Want作为载体将这些数据传递给UIAbilityB。
说明:
本模块首批接口从API version 9 开始支持。后续版本的新增接口,采用上角标单独标记接口的起始版本。
导入模块
import Want from '@ohos.app.ability.Want';
属性
系统能力:以下各项对应的系统能力均为SystemCapability.Ability.AbilityBase
名称 | 类型 | 必填 | 说明 |
---|---|---|---|
deviceId | string | 否 | 表示运行指定Ability的设备ID。如果未设置该字段,则表明指定本设备。 |
bundleName | string | 否 | 表示待启动Ability所在的应用Bundle名称。 |
moduleName | string | 否 | 表示待启动的Ability所属的模块名称。 |
abilityName | string | 否 | 表示待启动Ability名称。如果在Want中该字段同时指定了BundleName和AbilityName,则Want可以直接匹配到指定的Ability。AbilityName需要在一个应用的范围内保证唯一。 |
action | string | 否 | 表示要执行的通用操作(如:查看、分享、应用详情)。在隐式Want中,您可以定义该字段,配合uri或parameters来表示对数据要执行的操作。隐式Want定义及匹配规则请参见显式Want与隐式Want匹配规则。 |
entities | Array<string> | 否 | 表示目标Ability额外的类别信息(如:浏览器、视频播放器)。在隐式Want中是对action字段的补充。在隐式Want中,您可以定义该字段,来过滤匹配Ability类型。 |
uri | string | 否 | 表示携带的数据,一般配合type使用,指明待处理的数据类型。如果在Want中指定了uri,则Want将匹配指定的Uri信息,包括scheme 、schemeSpecificPart 、authority 和path 信息。 |
type | string | 否 | 表示MIME type类型描述,打开文件的类型,主要用于文管打开文件。比如:’text/xml’ 、 ‘image/*‘等,MIME定义请参见https://www.iana.org/assignments/media-types/media-types.xhtml?utm_source=ld246.com。 |
parameters | {[key: string]: any} | 否 | 表示WantParams描述,由开发者自行决定传入的键值对。默认会携带以下key值: - ohos.aafwk.callerPid:表示拉起方的pid。 - ohos.aafwk.param.callerBundleName:表示拉起方的Bundle Name。 - ohos.aafwk.param.callerToken:表示拉起方的token。 - ohos.aafwk.param.callerUid:表示BundleInfo中的uid,应用包里应用程序的uid。 - component.startup.newRules:表示是否启用新的管控规则。 - moduleName:表示拉起方的模块名,该字段的值即使定义成其他字符串,在传递到另一端时会被修改为正确的值。 - ohos.dlp.params.sandbox:表示dlp文件才会有。 - ability.params.backToOtherMissionStack:表示是否支持跨任务链返回。 |
flags | number | 否 | 表示处理Want的方式。默认传数字。 例如通过wantConstant.Flags.FLAG_ABILITY_CONTINUATION表示是否以设备间迁移方式启动Ability。 |
示例:
- 基础用法:在UIAbility对象中调用,示例中的context的获取方式请参见获取UIAbility的上下文信息。
import common from '@ohos.app.ability.common';
import Want from '@ohos.app.ability.Want';
let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext
let want: Want = {
deviceId: '', // deviceId为空表示本设备
bundleName: 'com.example.myapplication',
abilityName: 'FuncAbility',
moduleName: 'entry' // moduleName非必选
};
context.startAbility(want, (err) => {
// 显式拉起Ability,通过bundleName、abilityName和moduleName可以唯一确定一个Ability
console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`);
});
目前支持的数据类型有:字符串、数字、布尔、对象、数组和文件描述符等。
字符串(String)
import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', parameters: { keyForString: 'str', }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
数字(Number)
import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', parameters: { keyForInt: 100, keyForDouble: 99.99, }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
布尔(Boolean)
import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', parameters: { keyForBool: true, }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
对象(Object)
import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', parameters: { keyForObject: { keyForObjectString: 'str', keyForObjectInt: -200, keyForObjectDouble: 35.5, keyForObjectBool: false, }, }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
数组(Array)
import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', parameters: { keyForArrayString: ['str1', 'str2', 'str3'], keyForArrayInt: [100, 200, 300, 400], keyForArrayDouble: [0.1, 0.2], keyForArrayObject: [{ obj1: 'aaa' }, { obj2: 100 }], }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
文件描述符(FD)
import fs from '@ohos.file.fs'; import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; import { BusinessError } from '@ohos.base'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let fd: number = 0; try { fd = fs.openSync('/data/storage/el2/base/haps/pic.png').fd; } catch(err) { let code = (err as BusinessError).code; let message = (err as BusinessError).message; console.error(`Failed to openSync. Code: ${code}, message: ${message}`); } let want: Want = { deviceId: '', // deviceId为空表示本设备 bundleName: 'com.example.myapplication', abilityName: 'FuncAbility', moduleName: 'entry', // moduleName非必选 parameters: { 'keyFd': { 'type': 'FD', 'value': fd } // {'type':'FD', 'value':fd}是固定用法,用于表示该数据是FD } }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
parameter参数用法:
- 以ability.params.backToOtherMissionStack为例,ServiceExtension在拉起UIAbility的时候,可以支持跨任务链返回。
// (1) UIAbility1启动一个ServiceExtension import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication1', abilityName: 'ServiceExtensionAbility', }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
// (2) 该ServiceExtension去启动另一个UIAbility2,并在启动的时候携带参数ability.params.backToOtherMissionStack为true import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.ServiceExtensionContext; // ServiceExtensionContext let want: Want = { bundleName: 'com.example.myapplication2', abilityName: 'MainAbility', parameters: { "ability.params.backToOtherMissionStack": true, }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
说明:上例中,如果ServiceExtension启动UIAbility2时不携带ability.params.backToOtherMissionStack参数,或者携带的ability.params.backToOtherMissionStack参数为false,则UIAbility1和UIAbility2不在同一个任务栈里面,在UIAbility2的界面点back键,不会回到UIAbility1的界面。如果携带的ability.params.backToOtherMissionStack参数为true,则表示支持跨任务链返回,此时在UIAbility2的界面点back键,会回到UIAbility1的界面。
- parameter携带开发者自定义参数,由UIAbilityA传递给UIAbilityB,并在UIAbilityB中进行获取。
// (1) UIAbilityA通过startability启动UIAbilityB import common from '@ohos.app.ability.common'; import Want from '@ohos.app.ability.Want'; let context = getContext(this) as common.UIAbilityContext; // UIAbilityContext let want: Want = { bundleName: 'com.example.myapplication', abilityName: 'UIAbilityB', parameters: { developerParameters: 'parameters', }, }; context.startAbility(want, (err) => { console.error(`Failed to startAbility. Code: ${err.code}, message: ${err.message}`); });
// (2) 以UIAbilityB实例首次启动为例,会进入到UIAbilityB的onCreate生命周期 import UIAbility from '@ohos.app.ability.UIAbility'; import AbilityConstant from '@ohos.app.ability.AbilityConstant'; import Want from '@ohos.app.ability.Want'; class UIAbilityB extends UIAbility { onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) { console.log(`onCreate, want parameters: ${want.parameters.developerParameters}`); } }
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