# [Unity Engine] 關於我在Unity中踩的一些坑 - UI篇

###### tags: `TODO` `Unity Engine`
:::success
:sunglasses: 持續更新中....因為坑只會越踩越多
:::

## 按鈕點下去沒反應...
:::info
UI Button不能按可能來自以下這幾個原因
==請先利用`EventSystem`查看點到甚麼物件==
1. Button沒有Raycast Target(預設為Image元件)，或是Raycast Target沒有打勾(為false)
2. Iteractable們有打勾(為false)
3. 如果Button的Parent Canvas是巢狀的，則該Canvas需要加上GraphicsRaycaster元件

// nested canvas
RectTransform
|
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+--- Canvas(1)
|
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+--- Canvas(2)
        |
        |
        +--- Button

4. 場景中沒有EventSystem
> Ref: [Can't click item](https://forum.unity.com/threads/cant-click-ui-buttons.431042/)
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## PointerEvent

Inherit from `BaseEventData`

- [Reference](https://www.twblogs.net/a/5c0a93fcbd9eee6fb37bc8ab)