1# Redirection Rules
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4Generally, UI redirection within an application is triggered by users. However, an application can call **startAbility()** to implement UI redirection.
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7The PageAbility has a UI. It can use **startAbility()** to start an ability that has a UI and is visible to users.
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10The **visible** field under **abilities** in the **config.json** file specifies whether an ability can be started by other application components.
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12**Table 1** Description of visible
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14| Name| Description| Initial Value Allowed|
15| -------- | -------- | -------- |
16| visible | Whether the ability can be called by other applications.<br>**true**: The ability can be called by any application.<br>**false**: The ability can be called only by other components of the same application.| Yes (initial value: **false**)|
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19To enable an ability to be called by any application, configure the **config.json** file as follows:
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21```json
22{
23  "module": {
24    ...
25    "abilities": [
26      {
27        "visible": "true",
28        ...
29      }
30    ]
31  }
32}
33```
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36If the ability contains **skills**, you are advised to set **visible** to **true** so that the ability can be [implicitly started](explicit-implicit-want-mappings.md) by other applications. If this attribute is set to **false**, the system returns **PERMISSION_DENIED** when other applications attempt to start the ability. In this case, a system application can request the <!--Del-->[<!--DelEnd-->START_INVISIBLE_ABILITY<!--Del-->](../security/AccessToken/permissions-for-system-apps.md#ohospermissionstart_invisible_ability)<!--DelEnd--> permission to start the ability. Example abilities with **visible** set to **false** are the home screen, voice assistant, or search assistant.
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