1# WindowExtensionContext 2 3The **WindowExtensionContext** module, inherited from [ExtensionContext](js-apis-inner-application-extensionContext.md), is the context environment of the WindowExtensionAbility. 4 5The **WindowExtensionContext** module provides the capabilities of the [WindowExtensionAbility](js-apis-application-windowExtensionAbility.md), including starting the ability. 6 7> **NOTE** 8> 9> - 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. 10> 11> - The APIs provided by this module are system APIs. 12> 13> - The APIs of this module can be used only in the stage model. 14 15## Usage 16 17Before using the **WindowExtensionContext** module, you must define a child class that inherits from **WindowExtensionAbility**. 18 19```ts 20import WindowExtensionAbility from '@ohos.application.WindowExtensionAbility'; 21import WindowExtensionContext from 'application/WindowExtensionContext'; 22 23let context: WindowExtensionContext | null = null; 24 25class WindowExtAbility extends WindowExtensionAbility { 26 onConnect() { 27 context = this.context; // Obtain a WindowExtensionContext instance. 28 } 29} 30``` 31 32## WindowExtensionContext.startAbility 33 34startAbility(want: Want, options: StartOptions, callback: AsyncCallback<void>): void 35 36Starts an ability. This API uses an asynchronous callback to return the result. 37 38**System capability**: SystemCapability.WindowManager.WindowManager.Core 39 40**Parameters** 41 42| Name| Type| Mandatory| Description| 43| -------- | -------- | -------- | -------- | 44| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability.| 45| options | [StartOptions](js-apis-app-ability-startOptions.md) | Yes| Parameters used for starting the ability.| 46| callback | AsyncCallback<void> | Yes| Callback used to return the result.| 47 48**Example** 49 50 ```ts 51import { BusinessError } from '@ohos.base'; 52import Want from '@ohos.app.ability.Want'; 53import StartOptions from '@ohos.app.ability.StartOptions'; 54 55let want: Want = { 56 bundleName: 'com.example.myapplication', 57 abilityName: 'MainAbility' 58}; 59let options: StartOptions = { 60 windowMode: 102 61}; 62 63try { 64 this.context.startAbility(want, options, (error: BusinessError) => { 65 let message = (error as BusinessError).message; 66 let errCode = (error as BusinessError).code; 67 if (errCode) { 68 // Process service logic errors. 69 console.error('startAbility failed, error.code: ${errCode}, error.message: ${message}'); 70 return; 71 } 72 // Carry out normal service processing. 73 console.log('startAbility succeed'); 74 }); 75} catch (paramError) { 76 // Process input parameter errors. 77 let message = (paramError as BusinessError).message; 78 let errCode = (paramError as BusinessError).code; 79 console.error('error.code: ${errCode}, error.message: ${message}'); 80} 81 ``` 82 83## WindowExtensionContext.startAbility 84 85startAbility(want: Want, options?: StartOptions): Promise\<void> 86 87Starts an ability. This API uses a promise to return the result. 88 89**System capability**: SystemCapability.WindowManager.WindowManager.Core 90 91**Parameters** 92 93| Name| Type| Mandatory| Description| 94| -------- | -------- | -------- | -------- | 95| want | [Want](js-apis-app-ability-want.md) | Yes| Want information about the target ability, such as the ability name and bundle name.| 96| options | [StartOptions](js-apis-app-ability-startOptions.md) | No| Parameters used for starting the ability.| 97 98**Return value** 99 100| Type| Description| 101| -------- | -------- | 102| Promise<void> | Promise that returns no value.| 103 104**Example** 105 106 ```ts 107import { BusinessError } from '@ohos.base'; 108import Want from '@ohos.app.ability.Want'; 109import StartOptions from '@ohos.app.ability.StartOptions'; 110 111let want: Want = { 112 bundleName: 'com.example.myapp', 113 abilityName: 'MainAbility' 114}; 115let options: StartOptions = { 116 windowMode: 102, 117}; 118 119try { 120 this.context.startAbility(want, options) 121 .then(() => { 122 // Carry out normal service processing. 123 console.log('startAbility succeed'); 124 }) 125 .catch((error: BusinessError) => { 126 // Process service logic errors. 127 let message = (error as BusinessError).message; 128 let errCode = (error as BusinessError).code; 129 console.error('startAbility failed, error.code: ${errCode}, error.message: ${message}'); 130 }); 131} catch (paramError) { 132 // Process input parameter errors. 133 let message = (paramError as BusinessError).message; 134 let errCode = (paramError as BusinessError).code; 135 console.error('error.code: ${errCode}, error.message: ${message}'); 136} 137 ``` 138