@alifd/overlay/demo/autoAdjust.md

overlay base component

---
title: 自动更换位置
order: 7
---

能够根据空间大小自动更换 placement

> 若调整后位置始终不符合预期，可能是渲染过程中overlay内容宽度发生了变化导致计算错误，可以尝试固定overlay内容宽度来解决

```jsx
import { useState } from 'react';
import Overlay from '@alifd/overlay';

const { Popup } = Overlay;
const style = {
  width: 200,
  height: 100,
  padding: 10,
  background: '#fff',
  borderRadius: 2,
  boxShadow: '2px 2px 20px rgba(0, 0, 0, 0.15)',
};

const App = () => {
  const [position, setPosition] = useState({});

  return (
    <div
      style={{
        position: 'relative',
        height: 200,
        padding: 20,
        border: '1px solid #eee',
        overflow: 'auto',
      }}
    >
      <div>
        <Popup
          overlay={<div style={style}>上面空间不够</div>}
          placement="tl"
          triggerType="click"
          followTrigger
        >
          <button>TL-> BL</button>
        </Popup>
        <Popup
          overlay={<div style={style}>上面空间不够</div>}
          placement="t"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginLeft: 10 }}>T -> B</button>
        </Popup>
        <Popup
          overlay={<div style={style}>上面空间不够</div>}
          placement="tr"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginLeft: 10 }}>TR -> BR</button>
        </Popup>
        <Popup
          overlay={<div style={style}>上面空间不够</div>}
          placement="tl"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginTop: 0, float: 'right', right: 0 }}>TL-> BR</button>
        </Popup>
      </div>

      <br />
      <div>
        <Popup
          overlay={<div style={style}>左边空间不够</div>}
          placement="lt"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginTop: 0 }}>LT-> RT</button>
        </Popup>
        <Popup
          overlay={<div style={style}>右边空间不够</div>}
          placement="rt"
          triggerType="click"
          followTrigger
        >
          <button style={{ float: 'right', right: 0 }}>RT-> LT</button>
        </Popup>

        <br />
        <br />
        <Popup
          overlay={<div style={style}>左边空间不够</div>}
          placement="lb"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginTop: 0 }}>LB-> RB</button>
        </Popup>
        <Popup
          overlay={<div style={style}>右边空间不够</div>}
          placement="rb"
          triggerType="click"
          followTrigger
        >
          <button style={{ float: 'right', right: 0 }}>RB-> LB</button>
        </Popup>
        <br />
        <br />
        <Popup
          overlay={<div style={style}>左边、下边空间不够</div>}
          placement="l"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginTop: 0 }}>L-> R</button>
        </Popup>
        <Popup
          overlay={<div style={style}>右边空间不够</div>}
          placement="r"
          triggerType="click"
          followTrigger
        >
          <button style={{ float: 'right', right: 0 }}>R-> L</button>
        </Popup>
      </div>

      <br />
      <div>
        <Popup
          overlay={<div style={style}>下边/左边空间都不够</div>}
          placement="b"
          triggerType="click"
          followTrigger
        >
          <button>B -> T</button>
        </Popup>
        <Popup
          overlay={<div style={style}>下边/左边空间都不够</div>}
          placement="br"
          triggerType="click"
          followTrigger
        >
          <button style={{ marginLeft: 10 }}>BR -> TL</button>
        </Popup>
        <Popup
          overlay={<div style={style}>右边空间不够</div>}
          placement="bl"
          triggerType="click"
          followTrigger
        >
          <button style={{ float: 'right', right: 0 }}>BL-> TR</button>
        </Popup>
      </div>
    </div>
  );
};

ReactDOM.render(<App />, mountNode);
```