1# UIAbility Overview
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3
4## Overview
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6UIAbility is a type of application component that provides the UI for user interactions.
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8The following design philosophy is behind UIAbility:
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101. Native support for cross-device migration and multi-device collaboration at the application component level
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122. Support for multiple device types and window modes
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17UIAbility is the basic unit of scheduling in OpenHarmony and provides a window for applications to draw the UI. An application can contain one or more UIAbility components. For example, for a payment application, you can use separate UIAbility components to carry the entry and payment functionalities.
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19Each UIAbility component instance is displayed as a mission in the system application Recents.
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21You can develop a single UIAbility or multiple UIAbilities for your application based on service requirements.
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23- If you want your application to be displayed as one mission in **Recents**, use the pattern of "one UIAbility + multiple pages" to avoid unnecessary resource loading.
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25- If you want your application to be displayed as multiple missions in **Recents** or to have multiple windows opened simultaneously, use multiple UIAbilities to implement different features.
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27   For example, if you develop the message list and the audio/video call of an instant messaging application using different UIAbilities, users can easily switch from one window to another or display both windows in split-screen mode on the same screen.
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29> **NOTE**
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31> **Recents** is used for quickly viewing and managing all missions or applications running on the current device.
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33## Declaration Configuration
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35To enable an application to properly use a UIAbility component, declare the UIAbility name, entry, and label under [abilities](../quick-start/module-configuration-file.md#abilities) in the [module.json5 file](../quick-start/module-configuration-file.md).
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37
38```json
39{
40  "module": {
41    // ...
42    "abilities": [
43      {
44        "name": "EntryAbility", // Name of the UIAbility component.
45        "srcEntry": "./ets/entryability/EntryAbility.ets", // Code path of the UIAbility component.
46        "description": "$string:EntryAbility_desc", // Description of the UIAbility component.
47        "icon": "$media:icon", // Icon of the UIAbility component.
48        "label": "$string:EntryAbility_label", // Label of the UIAbility component.
49        "startWindowIcon": "$media:icon", // Index of the icon resource file.
50        "startWindowBackground": "$color:start_window_background", // Index of the background color resource file.
51        // ...
52      }
53    ]
54  }
55}
56```
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