vue3使用自定义指令实现eldialog拖拽功能示例详解

import dialogDrag from './_dialog-drag'
import { watch } from 'Vue'
const _dialogDrag = {
  // mounted 
  mounted (el: any, binding: any) {
    // 监听 dialog 是否显示的状态
    watch (binding.value, () => {
      // dialog 不可见，退出
      if (!binding.value.visible) return
      // 寻找 el-dialog 组件
      const container = el.firstElementChild.firstElementChild
      // 已经设置拖拽事件，退出
      if (container.onmousemove) return
      // 等待 DOM 渲染完毕
      setTimeout(() => {
        // 拖拽的 “句柄”
        const _dialogTitle = el.getElementsByClassName('el-dialog__header')
        if (_dialogTitle.length === 0) {
          // 还没有渲染完毕，或则其他原因
          console.warn('没有找到要拖拽的 el-dialog', el)
        } else {
          const { setDialog } = dialogDrag()
          const dialogTitle = _dialogTitle[0]
          // 弹窗
          const dialog = el.firstElementChild.firstElementChild.firstElementChild
          // 通过 CSS 寻找 el-dialog 设置的宽度
          const arr = dialog.style.cssText.split(';')
          const width = arr[0].replace('%', '').replace('--el-dialog-width:', '') //
          // 设置 el-dialog 组件、弹窗、句柄、宽度
          setDialog(container, dialog, dialogTitle, width)
        }
      },300)
    })
  },
}

const install = (app: any, options: any) => {
  app.directive('dialogDrag', _dialogDrag)
}
export {
  _dialogDrag,
  install
}

export default function dialogDrag () {
  
  const setDialog = (container: any, dialog: any, dialogTitle: any, width: number) => {
    const oldCursor = dialogTitle.style.cursor
    // 可视窗口的宽度
    const clientWidth = document.documentElement.clientWidth
    // 可视窗口的高度
    const clientHeight = document.documentElement.clientHeight
    // 根据百分数计算宽度
    const tmpWidth = clientWidth * (100 - width) / 200
    // 默认宽度和高度
    const domset = {
      x: tmpWidth,
      y: clientHeight * 15 / 100 // 根据 15vh 计算
    }
    // 查看dialog 当前的宽度和高低
    if (dialog.style.marginLeft === '') {
      dialog.style.marginLeft = domset.x + 'px'
    } else {
      domset.x = dialog.style.marginLeft.replace('px','') * 1
    }
    if (dialog.style.marginTop === '') {
      dialog.style.marginTop = domset.y + 'px'
    } else {
      domset.y = dialog.style.marginTop.replace('px','') * 1
    }
    // 记录拖拽开始的光标坐标，0 表示没有拖拽
    const start = { x: 0, y: 0 }
    // 移动中记录偏移量
    const move = { x: 0, y: 0 }
    // 经过时改变鼠标指针形状
    dialogTitle.onmouseover = () => {
      dialogTitle.style.cursor = 'move' // 改变光标形状
    }
    // 鼠标按下，开始拖拽
    dialogTitle.onmousedown = (e: any) => {
      start.x = e.clientX
      start.y = e.clientY
      dialogTitle.style.cursor = 'move' // 改变光标形状
    }
    // 鼠标移动，实时跟踪 dialog
    container.onmousemove = (e: any) => {
      if (start.x === 0) { // 不是拖拽状态
        return
      }
      move.x = e.clientX - start.x
      move.y = e.clientY - start.y
      // 初始位置 + 拖拽距离
      dialog.style.marginLeft = (domset.x + move.x) + 'px'
      dialog.style.marginTop = (domset.y + move.y) + 'px'
    }
    // 鼠标抬起，结束拖拽
    container.onmouseup = (e: any) => {
      if (start.x === 0) { // 不是拖拽状态
        return
      }
      move.x = e.clientX - start.x
      move.y = e.clientY - start.y
      // 记录新坐标，作为下次拖拽的初始位置
      domset.x += move.x
      domset.y += move.y
      dialogTitle.style.cursor = oldCursor
      dialog.style.marginLeft = domset.x + 'px'
      dialog.style.marginTop = domset.y + 'px'
      // 结束拖拽
      start.x = 0
    }
  }
  return {
    setDialog // 设置
  }
}

<template>
  <!--拖拽-->
  <el-button @click="dialog.visible = true">打开</el-button>
  <div v-dialog-drag="dialog" >
    <el-dialog
      v-model="dialog.visible"
      title="自定义拖拽2"
      width="25%"
    >
      <span>拖拽测试</span>
      <template #footer>
        <span class="dialog-footer">
          <el-button @click="dialog.visible = false">Cancel</el-button>
          <el-button type="primary" @click="dialog.visible = false">Confirm</el-button>
        </span>
      </template>
    </el-dialog>
  </div>
</template>
<script lang="ts">
  import { defineComponent, ref, reactive } from 'vue'
  import { _dialogDrag } from '../../../lib/main'
  export default defineComponent({
    name: 'nf-dialog-move',
    directives: {
      dialogDrag: _dialogDrag
    },
    props: {
    },
    setup(props, context) {
      const dialog = reactive({
        visible: false
      })
      return {
        meta,
        dialog
      }
    }
  })
</script>