@ohos.application.Want (Want)

Want is a carrier for information transfer between objects (application components). Want can be used as a parameter of startAbility() to specify a startup target and information that needs to be carried during startup, for example, bundleName and abilityName, which respectively indicate the bundle name of the target ability and the ability name in the bundle. When ability A needs to start ability B and transfer some data to ability B, it can use Want a carrier to transfer the data.

NOTE

The APIs of this module are supported since API version 8 and deprecated since API version 9. You are advised to use @ohos.app.ability.Want instead. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import Want from '@ohos.application.Want';

Attributes

System capability: SystemCapability.Ability.AbilityBase

Example

• Basic usage (called in a UIAbility object, where context in the example is the context object of the UIAbility).

  import Want from '@ohos.application.Want';
  import { BusinessError } from '@ohos.base';
  import UIAbility from '@ohos.app.ability.UIAbility';
  import AbilityConstant from '@ohos.app.ability.AbilityConstant';
  
  let want: Want = {
  'deviceId': '', // An empty deviceId indicates the local device.
  'bundleName': 'com.example.myapplication',
  'abilityName': 'EntryAbility',
  };
  class MyAbility extends UIAbility{
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam){
      this.context.startAbility(want, (error: BusinessError) => {
      // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
      console.error(`error.code = ${error.code}`);
      });
  }
  }
  

• Data is transferred through user-defined fields. The following data types are supported (called in a UIAbility object, where context in the example is the context object of the UIAbility):

  • String

    import Want from '@ohos.application.Want';
    
    let want: Want = {
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility',
        parameters: {
            keyForString: 'str',
        },
    };
    

  • Number

    import Want from '@ohos.application.Want';
    
    let want: Want = {
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility',
        parameters: {
            keyForInt: 100,
            keyForDouble: 99.99,
        },
    };
    

  • Boolean

    import Want from '@ohos.application.Want';
    
    let want: Want = {
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility',
        parameters: {
            keyForBool: true,
        },
    };
    

  • Object

    import Want from '@ohos.application.Want';
    
    let want: Want = {
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility',
        parameters: {
            keyForObject: {
                keyForObjectString: 'str',
                keyForObjectInt: -200,
                keyForObjectDouble: 35.5,
                keyForObjectBool: false,
            },
        },
    };
    

  • Array

    import Want from '@ohos.application.Want';
    
    let want: Want = {
        bundleName: 'com.example.myapplication',
        abilityName: 'EntryAbility',
        parameters: {
            keyForArrayString: ['str1', 'str2', 'str3'],
            keyForArrayInt: [100, 200, 300, 400],
            keyForArrayDouble: [0.1, 0.2],
            keyForArrayObject: [{obj1: 'aaa'}, {obj2: 100}],
        },
    };
    

  • File descriptor (FD)

    import fs from '@ohos.file.fs';
    import Want from '@ohos.application.Want';
    import { BusinessError } from '@ohos.base';
    import AbilityConstant from '@ohos.app.ability.AbilityConstant';
    import UIAbility from '@ohos.app.ability.UIAbility';
    
    
    let fd: number = 0;
    try {
    fd = fs.openSync('/data/storage/el2/base/haps/pic.png').fd;
    } catch(e) {
    console.error(`openSync fail: ${JSON.stringify(e)}`);
    }
    let want: Want = {
    deviceId: '', // An empty deviceId indicates the local device.
    bundleName: 'com.example.myapplication',
    abilityName: 'EntryAbility',
    parameters: {
        'keyFd':{'type':'FD', 'value':fd}
    }
    };
    
    class MyAbility extends UIAbility{
    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam){
        this.context.startAbility(want, (error: BusinessError) => {
        // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
        console.error(`error.code = ${error.code}`);
        });
    }
    }
    

• For more details and examples, see Want.