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 6 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.

System capability: SystemCapability.Ability.AbilityBase

Name Type Mandatory Description
deviceId string No ID of the device running the ability.
bundleName string No Bundle name. If both bundleName and abilityName are specified in a Want, the Want can directly match the specified ability.
abilityName string No Name of the ability. If both bundleName and abilityName are specified in a Want object, the Want object can match a specific ability. The value of abilityName must be unique in an application.
uri string No URI. If uri is specified in a Want object, the Want object will match the specified URI information, including scheme, schemeSpecificPart, authority, and path.
type string No MIME type, that is, the type of the file to open, for example, 'text/xml' and 'image/*'. For details about the MIME type definition, see https://www.iana.org/assignments/media-types/media-types.xhtml?utm_source=ld246.com.
flags number No How the Want object will be handled. By default, numbers are passed in. For details, see flags.
action string No Action to take, such as viewing and sharing application details. In implicit Want, you can define this field and use it together with uri or parameters to specify the operation to be performed on the data.
parameters {[key: string]: Object} No Want parameters in the form of custom key-value (KV) pairs. By default, the following keys are carried:
- ohos.aafwk.callerPid: PID of the caller.
- ohos.aafwk.param.callerToken: token of the caller.
- ohos.aafwk.param.callerUid: UID in bundleInfo, that is, the application UID in the bundle information.
- component.startup.newRules: whether to enable the new control rule.
- moduleName: module name of the caller. No matter what this field is set to, the correct module name will be sent to the peer.
- ohos.dlp.params.sandbox: available only for DLP files.
entities Array<string> No Additional category information (such as browser and video player) of the target ability. It is a supplement to action in implicit Want and is used to filter ability types.
moduleName9+ string No Module to which the ability belongs.

Example

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

    let want = {
    'deviceId': '', // An empty deviceId indicates the local device.
    'bundleName': 'com.extreme.test',
    'abilityName': 'MainAbility',
    'moduleName': 'entry' // moduleName is optional.
};
this.context.startAbility(want, (error) => {
    // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
    console.log('error.code = ' + error.code)
});

  • Passing a file descriptor (FD) (called in the UIAbility object, where context in the example is the context object of the UIAbility):

    import fs from '@ohos.file.fs';

// ...
let fd;
try {
    fd = fs.openSync('/data/storage/el2/base/haps/pic.png').fd;
} catch(e) {
    console.log('openSync fail:' + JSON.stringify(e));
}
let want = {
    'deviceId': '', // An empty deviceId indicates the local device.
    'bundleName': 'com.extreme.test',
    'abilityName': 'MainAbility',
    'moduleName': 'entry', // moduleName is optional.
    'parameters': {
        'keyFd':{'type':'FD', 'value':fd}
    }
};
this.context.startAbility(want, (error) => {
    // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
    console.log('error.code = ' + error.code)
});
// ...

  • For more details and examples, see Want.