1# UIAbility组件基本用法
2
3
4[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)组件的基本用法包括：指定UIAbility的启动页面以及获取UIAbility的上下文[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)。
5
6
7## 指定UIAbility的启动页面
8
9应用中的[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)在启动过程中，需要指定启动页面，否则应用启动后会因为没有默认加载页面而导致白屏。可以在UIAbility的[onWindowStageCreate()](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md#uiabilityonwindowstagecreate)生命周期回调中，通过[WindowStage](../reference/apis-arkui/js-apis-window.md#windowstage9)对象的[loadContent()](../reference/apis-arkui/js-apis-window.md#loadcontent9)方法设置启动页面。
10
11
12```ts
13import { UIAbility } from '@kit.AbilityKit';
14import { window } from '@kit.ArkUI';
15
16export default class EntryAbility extends UIAbility {
17  onWindowStageCreate(windowStage: window.WindowStage): void {
18    // Main window is created, set main page for this ability
19    windowStage.loadContent('pages/Index', (err, data) => {
20      // ...
21    });
22  }
23  // ...
24}
25```
26
27> **说明：**
28> 在DevEco Studio中创建的UIAbility中，该UIAbility实例默认会加载Index页面，根据需要将Index页面路径替换为需要的页面路径即可。
29
30
31## 获取UIAbility的上下文信息
32
33[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)类拥有自身的上下文信息，该信息为[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)类的实例，[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)类拥有abilityInfo、currentHapModuleInfo等属性。通过UIAbilityContext可以获取UIAbility的相关配置信息，如包代码路径、Bundle名称、Ability名称和应用程序需要的环境状态等属性信息，以及可以获取操作UIAbility实例的方法（如[startAbility()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#uiabilitycontextstartability)、[connectServiceExtensionAbility()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#uiabilitycontextconnectserviceextensionability)、[terminateSelf()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#uiabilitycontextterminateself)等）。
34如果需要在页面中获得当前Ability的Context，可调用[getContext](../reference/apis-arkui/js-apis-getContext.md#getcontext)接口获取当前页面关联的UIAbilityContext或[ExtensionContext](../reference/apis-ability-kit/js-apis-inner-application-extensionContext.md)。
35
36- 在UIAbility中可以通过`this.context`获取UIAbility实例的上下文信息。
37
38  ```ts
39  import { UIAbility, AbilityConstant, Want } from '@kit.AbilityKit';
40
41  export default class EntryAbility extends UIAbility {
42    onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
43      // 获取UIAbility实例的上下文
44      let context = this.context;
45      // ...
46    }
47  }
48  ```
49
50- 在页面中获取UIAbility实例的上下文信息，包括导入依赖资源context模块和在组件中定义一个context变量两个部分。
51
52  ```ts
53  import { common, Want } from '@kit.AbilityKit';
54
55  @Entry
56  @Component
57  struct Page_EventHub {
58    private context = getContext(this) as common.UIAbilityContext;
59
60    startAbilityTest(): void {
61      let want: Want = {
62        // Want参数信息
63      };
64      this.context.startAbility(want);
65    }
66
67    // 页面展示
68    build() {
69      // ...
70    }
71  }
72  ```
73
74  也可以在导入依赖资源context模块后，在具体使用[UIAbilityContext](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md)前进行变量定义。
75
76
77  ```ts
78  import { common, Want } from '@kit.AbilityKit';
79
80  @Entry
81  @Component
82  struct Page_UIAbilityComponentsBasicUsage {
83    startAbilityTest(): void {
84      let context = getContext(this) as common.UIAbilityContext;
85      let want: Want = {
86        // Want参数信息
87      };
88      context.startAbility(want);
89    }
90
91    // 页面展示
92    build() {
93      // ...
94    }
95  }
96  ```
97
98- 当业务完成后，开发者如果想要终止当前[UIAbility](../reference/apis-ability-kit/js-apis-app-ability-uiAbility.md)实例，可以在通过调用[terminateSelf()](../reference/apis-ability-kit/js-apis-inner-application-uiAbilityContext.md#uiabilitycontextterminateself)方法实现。
99
100  ```ts
101  import { common } from '@kit.AbilityKit';
102  import { BusinessError } from '@kit.BasicServicesKit';
103
104  @Entry
105  @Component
106  struct Page_UIAbilityComponentsBasicUsage {
107    // 页面展示
108    build() {
109      Column() {
110        //...
111        Button('FuncAbilityB')
112          .onClick(() => {
113            let context = getContext(this) as common.UIAbilityContext;
114            try {
115              context.terminateSelf((err: BusinessError) => {
116                if (err.code) {
117                  // 处理业务逻辑错误
118                  console.error(`terminateSelf failed, code is ${err.code}, message is ${err.message}`);
119                  return;
120                }
121                // 执行正常业务
122                console.info('terminateSelf succeed');
123              });
124            } catch (err) {
125              // 捕获同步的参数错误
126              let code = (err as BusinessError).code;
127              let message = (err as BusinessError).message;
128              console.error(`terminateSelf failed, code is ${code}, message is ${message}`);
129            }
130          })
131      }
132    }
133  }
134  ```
135