React實(shí)現(xiàn)多個(gè)場(chǎng)景下鼠標(biāo)跟隨提示框詳解

更新時(shí)間：2022年09月30日 14:13:58 作者：xmanlin

這篇文章主要為大家介紹了React實(shí)現(xiàn)多個(gè)場(chǎng)景下鼠標(biāo)跟隨提示框詳解，有需要的朋友可以借鑒參考下，希望能夠有所幫助，祝大家多多進(jìn)步，早日升職加薪

前言

鼠標(biāo)跟隨框的作用如下圖所示，可以在前端頁(yè)面上，為我們后續(xù)的鼠標(biāo)操作進(jìn)行提示說(shuō)明，提升用戶的體驗(yàn)。本文將通過(guò)多種方式去實(shí)現(xiàn)，從而滿足不同場(chǎng)景下的需求。

實(shí)現(xiàn)原理

實(shí)現(xiàn)鼠標(biāo)跟隨框的原理很簡(jiǎn)單，就是監(jiān)聽(tīng)鼠標(biāo)在頁(yè)面上的坐標(biāo)，然后利用相對(duì)定位（position: relative;）、絕對(duì)定位（position: absolute;）和固定定位（position: fixed;）等相關(guān)知識(shí)。

本文是利用的 React，但只要知道原理，技術(shù)棧什么的問(wèn)題都不大。具體怎么實(shí)現(xiàn)，咱接著往下看。

固定定位實(shí)現(xiàn)

固定定位的好處是，相對(duì)于瀏覽器窗口定位，而鼠標(biāo)跟隨框的通用場(chǎng)景就是跟隨鼠標(biāo)移動(dòng)。

MousePositionDemo

我們先寫一個(gè)頁(yè)面，用來(lái)引入鼠標(biāo)跟隨框：

index.tsx

import React, { useEffect, useState  } from 'react';
import './index.less';
import { Button } from 'antd';
import MousePositionModal from './MousePositionModal';
const MousePositionDemo = () => {
    const [visible, setVisible] = useState(false);
    return (
        <div id="mouse-position-demo" className="mouse-position-demo">
            <Button onClick={() => {
                setVisible(true)
            }}>點(diǎn)擊顯示</Button>
            <Button onClick={() => {
                setVisible(false)
            }}>點(diǎn)擊關(guān)閉</Button>
            {/* 鼠標(biāo)跟隨框 */}
            <MousePositionModal
                visible={visible}
                content="鼠標(biāo)跟隨"
                defaultPosition={{
                    x: 32,
                    y: 32
                }}
            />
        </div>
    )
}
export default MousePositionDemo;

index.less

.mouse-position-demo {
    margin: 0 auto;
    height: 500px;
    width: 500px;
    background-color: #fff;
    padding: 24px 24px;
}

MousePositionModal

這里我們首先通過(guò) clientX, clientY 來(lái)返回當(dāng)事件被觸發(fā)時(shí)鼠標(biāo)指針相對(duì)于瀏覽器頁(yè)面（或客戶區(qū)）的水平和垂直坐標(biāo)。

當(dāng)然，僅這樣可能是不夠的，我們會(huì)發(fā)現(xiàn)在鼠標(biāo)靠近瀏覽器頁(yè)面最右側(cè)的時(shí)候，鼠標(biāo)跟隨框的部分頁(yè)面會(huì)被隱藏掉。為了能夠完整的展示鼠標(biāo)跟隨框中的信息，我們需要進(jìn)行一個(gè)簡(jiǎn)單的計(jì)算，當(dāng) 鼠標(biāo)位置的橫坐標(biāo) > 鼠標(biāo)位置橫坐標(biāo) - 鼠標(biāo)選擇框的寬度 時(shí)，就讓 鼠標(biāo)跟隨框的橫坐標(biāo) = 鼠標(biāo)位置橫坐標(biāo) - 鼠標(biāo)選擇框的寬度。

鼠標(biāo)跟隨框的具體實(shí)現(xiàn)如下：

index.tsx

import React, { useState, useEffect } from 'react';
import './index.less';
interface IMousePositionModal {
  visible: boolean;
  content: string;
  defaultPosition: {
    x: number,
    y: number
  }
}
const MousePositionModal = (props: IMousePositionModal) => {
  const { visible, content, defaultPosition } = props;
  const [left, setLeft] = useState(defaultPosition.x);
  const [top, setTop] = useState(defaultPosition.y);
  useEffect(() => {
    if (visible) {
      show();
    }
  }, [visible]);
  const show = () => {
    const modal = document.getElementById('mouse-position-modal');
    if (modal) {
      document.onmousemove = (event) => {
        const { clientX, clientY } = event || window.event;
        const clientWidth = document.body.clientWidth || document.documentElement.clientWidth;
        const { offsetWidth } = modal;
        let x = clientX + 18;
        const y = clientY + 18;
        if (x >= clientWidth - offsetWidth) {
          x = clientWidth - offsetWidth;
        }
        setLeft(x);
        setTop(y);
      };
    }
  };
  return (
    <div
      id="mouse-position-modal"
      className="mouse-position-modal"
      style={{ left: `${left}px`, top: `${top}px`, visibility: `${visible ? 'visible' : 'hidden'}`}}
    >
      <div className="mouse-position-modal-content">{content}</div>
    </div>
  );
};
export default MousePositionModal;

這里有兩個(gè)地點(diǎn)需要注意：一是給鼠標(biāo)跟隨框設(shè)置固定定位，二是要將 z-index 的值設(shè)置的足夠大，不然有可能會(huì)被頁(yè)面上的其他元素遮住。

index.less

.mouse-position-modal {
  min-width: 240px;
  height: 57px;
  background: #fff;
  box-shadow: 0 4px 12px 0 rgba(0, 0, 0, 0.15);
  border-radius: 4px;
  position: fixed;
  z-index: 2000;
  padding: 8px 12px;
  .mouse-position-modal-content {
    font-size: 16px;
    color: #262626;
  }
}

絕對(duì)定位（相對(duì)于整個(gè)瀏覽器窗口）

利用絕對(duì)定位我們可以實(shí)現(xiàn)和上面固定定位相似的效果，但是有個(gè)隱患需要注意，如果鼠標(biāo)跟隨框的某個(gè)相近的父元素用了相對(duì)定位，那鼠標(biāo)跟隨框的實(shí)際位置就可能會(huì)亂套了。

絕對(duì)定位不僅要考慮可視范圍內(nèi)的位置，還需要考慮瀏覽器頁(yè)面滾動(dòng)的距離。

具體實(shí)現(xiàn)如下：

MousePositionDemo

和固定定位一樣

MousePositionModal

index.tsx

import React, { useState, useEffect } from 'react';
import './index.less';
interface IMousePositionModal {
  visible: boolean;
  content: string;
  defaultPosition: {
    x: number,
    y: number
  }
}
const MousePositionModal = (props: IMousePositionModal) => {
  const { visible, content, defaultPosition } = props;
  const [left, setLeft] = useState(defaultPosition.x);
  const [top, setTop] = useState(defaultPosition.y);
  useEffect(() => {
    if (visible) {
      show();
    }
  }, [visible]);
  const show = () => {
    const modal = document.getElementById('mouse-position-modal');
    if (modal) {
      document.onmousemove = (event) => {
        const { clientX, clientY, pageX, pageY } = event || window.event;
        const sl = document.body.scrollLeft || document.documentElement.scrollLeft;
        const st = document.body.scrollTop || document.documentElement.scrollTop;
        const clientWidth = document.body.clientWidth || document.documentElement.clientWidth;
        const { offsetWidth } = modal;
        let x = (pageX || clientX + sl) + 18;
        const y = (pageY || clientY + st) + 18;
        if (x >= clientWidth - offsetWidth) {
          x = clientWidth - offsetWidth;
        }
        setLeft(x);
        setTop(y);
      };
    }
  };
  return (
    <div
      id="mouse-position-modal"
      className="mouse-position-modal"
      style={{ left: `${left}px`, top: `${top}px`, visibility: `${visible ? 'visible' : 'hidden'}`}}
    >
      <div className="mouse-position-modal-content">{content}</div>
    </div>
  );
};
export default MousePositionModal;

index.less

.mouse-position-modal {
  min-width: 240px;
  height: 57px;
  background: #fff;
  box-shadow: 0 4px 12px 0 rgba(0, 0, 0, 0.15);
  border-radius: 4px;
  position: absolute;
  z-index: 2000;
  padding: 8px 12px;
  .mouse-position-modal-content {
    font-size: 16px;
    color: #262626;
  }
}

絕對(duì)定位和相對(duì)定位（相對(duì)于鼠標(biāo)跟隨框的父元素）

有時(shí)候我們可能并不需要在整個(gè)頁(yè)面進(jìn)行鼠標(biāo)跟隨框的提示，在某些情況下只需要鼠標(biāo)在進(jìn)入頁(yè)面的部分區(qū)域才進(jìn)行提示。

如下圖所示：

這個(gè)時(shí)候就需要同時(shí)用到絕對(duì)定位和相對(duì)定位以及 offsetX 和 offsetY。

offsetX：規(guī)定了事件對(duì)象與目標(biāo)節(jié)點(diǎn)的內(nèi)填充邊（padding edge）在 X 軸方向上的偏移量 offsetY：規(guī)定了事件對(duì)象與目標(biāo)節(jié)點(diǎn)的內(nèi)填充邊（padding edge）在 Y 軸方向上的偏移量

具體實(shí)現(xiàn)如下：

MousePositionDemo

index.tsx

import React, { useEffect, useState  } from 'react';
import './index.less';
import { Button } from 'antd';
import MousePositionModal2 from './MousePositionModal2';
// 兼容offsetX
const getOffsetX = (e: any) =>{
    const event = e || window.event;
    const srcObj = e.target || e.srcElement;
    if (event.offsetX){
        return event.offsetX;
    }else{
        const rect = srcObj.getBoundingClientRect();
        const clientx = event.clientX;
        return clientx - rect.left;
    }
}
// 兼容offsetY
const getOffsetY = (e: any) => {
    const event = e || window.event;
    const srcObj = e.target || e.srcElement;
    if (event.offsetY){
        return event.offsetY;
    }else{
        const rect = srcObj.getBoundingClientRect();
        const clientx = event.clientY;
        return clientx - rect.top;
    }
}
const MousePositionDemo = () => {
    const [visible, setVisible] = useState(false);
    const [defaultPosition, setDefaultPosition] = useState({
        x: 32,
        y: 32
    })
    useEffect(() => {
        const ele = document.getElementById('mouse-position-demo') as HTMLElement;
        ele.addEventListener('mouseenter', show)
        ele.addEventListener('mousemove', mouseMove)
        ele.addEventListener('mouseleave', hide)
        return () => {
            ele.removeEventListener('mouseenter', show)
            ele.removeEventListener('mousemove', mouseMove)
            ele.removeEventListener('mouseleave', hide)
        }
    }, [])
    const show = () => {
        setVisible(true)
    }
    const hide = () => {
        setVisible(false)
    }
    const mouseMove = (e: MouseEvent) => {
        let x = getOffsetX(e) + 18;
        const y = getOffsetY(e) + 18;
        setDefaultPosition({ x, y });
    }
    return (
        <div id="mouse-position-demo" className="mouse-position-demo">
            <MousePositionModal2
                visible={visible}
                content="鼠標(biāo)跟隨"
                defaultPosition={defaultPosition}
            />
        </div>
    )
}
export default MousePositionDemo;

注意要將這里 position 設(shè)置為 relative 。

index.less

.mouse-position-demo {
    margin: 0 auto;
    height: 500px;
    width: 500px;
    background-color: #fff;
    padding: 24px 24px;
    position: relative;
}

MousePositionModal2

index.tsx

import React, { useState, useEffect } from 'react';
import './index.less';
interface IMousePositionModal {
  visible: boolean;
  content: string;
  defaultPosition: {
    x: number,
    y: number
  }
}
const MousePositionModal2 = (props: IMousePositionModal) => {
  const { visible, content, defaultPosition } = props;
  const { x, y } = defaultPosition;
  return (
    <div
      id="mouse-position-modal"
      className="mouse-position-modal"
      style={{ left: `${x}px`, top: `${y}px`, visibility: `${visible ? 'visible' : 'hidden'}` }}
    >
      <div className="mouse-position-modal-content">{content}</div>
    </div>
  );
};
export default MousePositionModal2;

注意要將這里 position 設(shè)置為 absolute 。

index.less

.mouse-position-modal {
  min-width: 240px;
  height: 57px;
  background: #fff;
  box-shadow: 0 4px 12px 0 rgba(0, 0, 0, 0.15);
  border-radius: 4px;
  position: absolute;
  z-index: 2000;
  padding: 8px 12px;
  .mouse-position-modal-content {
    font-size: 16px;
    color: #262626;
  }
}