1# @ohos.app.ability.Want (Want) 2 3Want 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 UIAbility A needs to start UIAbility B and transfer some data to UIAbility B, it can use Want a carrier to transfer the data. 4 5> **NOTE** 6> 7> The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version. 8 9## Modules to Import 10 11```ts 12import Want from '@ohos.app.ability.Want'; 13``` 14 15## Attributes 16 17**System capability**: SystemCapability.Ability.AbilityBase 18 19| Name | Type | Mandatory| Description | 20| ----------- | -------------------- | ---- | ------------------------------------------------------------ | 21| deviceId | string | No | ID of the device running the ability. | 22| bundleName | string | No | Bundle name of the ability. If both **bundleName** and **abilityName** are specified in a **Want** object, the **Want** object can match a specific ability. | 23| 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.| 24| uri | string | No| If **uri** is specified in a **Want**, the **Want** will match the specified URI information, including **scheme**, **schemeSpecificPart**, **authority**, and **path** components.| 25| 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.| 26| flags | number | No| How the **Want** object will be handled. By default, a number is passed in. For details, see [flags](js-apis-app-ability-wantConstant.md#wantconstantflags). | 27| 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. | 28| parameters | {[key: string]: any} | No | Want parameters in the form of custom key-value (KV) pairs. By default, the following keys are carried:<br>- **ohos.aafwk.callerPid**: PID of the caller.<br>- **ohos.aafwk.param.callerToken**: token of the caller.<br>- **ohos.aafwk.param.callerUid**: UID in [BundleInfo](js-apis-bundleManager-bundleInfo.md#bundleinfo-1), that is, the application UID in the bundle information.<br>- **component.startup.newRules**: whether to enable the new control rule.<br/>- **moduleName**: module name of the caller. No matter what this field is set to, the correct module name will be sent to the peer.<br/>- **ohos.dlp.params.sandbox**: available only for DLP files. | 29| entities | Array\<string> | No| Additional category information (such as browser and video player) of the ability. It is a supplement to the **action** field for implicit Want. and is used to filter ability types.| 30| moduleName | string | 否 | Module to which the ability belongs. | 31 32**Example** 33 34- Basic usage 35 36 ```ts 37 let want = { 38 'deviceId': '', // An empty deviceId indicates the local device. 39 'bundleName': 'com.extreme.test', 40 'abilityName': 'MainAbility', 41 'moduleName': 'entry' // moduleName is optional 42 }; 43 this.context.startAbility(want, (error) => { 44 // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability. 45 console.log('error.code = ' + error.code); 46 }) 47 ``` 48 49- Data is transferred through user-defined fields. The following data types are supported: 50 51 * String 52 ```ts 53 let want = { 54 bundleName: 'com.example.demo', 55 abilityName: 'com.example.demo.MainAbility', 56 parameters: { 57 keyForString: 'str', 58 }, 59 }; 60 ``` 61 * Number 62 ```ts 63 let want = { 64 bundleName: 'com.example.demo', 65 abilityName: 'com.example.demo.MainAbility', 66 parameters: { 67 keyForInt: 100, 68 keyForDouble: 99.99, 69 }, 70 }; 71 ``` 72 * Boolean 73 ```ts 74 let want = { 75 bundleName: 'com.example.demo', 76 abilityName: 'com.example.demo.MainAbility', 77 parameters: { 78 keyForBool: true, 79 }, 80 }; 81 ``` 82 * Object 83 ```ts 84 let want = { 85 bundleName: 'com.example.demo', 86 abilityName: 'com.example.demo.MainAbility', 87 parameters: { 88 keyForObject: { 89 keyForObjectString: 'str', 90 keyForObjectInt: -200, 91 keyForObjectDouble: 35.5, 92 keyForObjectBool: false, 93 }, 94 }, 95 }; 96 ``` 97 * Array 98 ```ts 99 let want = { 100 bundleName: 'com.example.demo', 101 abilityName: 'com.example.demo.MainAbility', 102 parameters: { 103 keyForArrayString: ['str1', 'str2', 'str3'], 104 keyForArrayInt: [100, 200, 300, 400], 105 keyForArrayDouble: [0.1, 0.2], 106 keyForArrayObject: [{obj1: 'aaa'}, {obj2: 100}], 107 }, 108 }; 109 ``` 110 * File descriptor (FD) 111 ```ts 112 import fileio from '@ohos.fileio'; 113 let fd; 114 try { 115 fd = fileio.openSync('/data/storage/el2/base/haps/pic.png'); 116 } catch(e) { 117 console.log('openSync fail:' + JSON.stringify(e)); 118 } 119 let want = { 120 'deviceId': '', // An empty deviceId indicates the local device. 121 'bundleName': 'com.extreme.test', 122 'abilityName': 'MainAbility', 123 'moduleName': 'entry', // moduleName is optional. 124 'parameters': { 125 'keyFd':{'type':'FD', 'value':fd} // {'type':'FD', 'value':fd} is a fixed usage, indicating that the data is a file descriptor. 126 } 127 }; 128 this.context.startAbility(want, (error) => { 129 // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability. 130 console.log('error.code = ' + error.code); 131 }); 132 ``` 133 134 135 136
