演示地址:

https://elementui.github.io/theme-chalk-preview/#/zh-CN

原理:

element ui 2.0版本之后是基于scss实现的,所有到颜色都是通过变量进行定义,所以我们可以通过修改变量来达到动态换肤的目的.

代码:

1.换肤组件:

ThemePicker

<template>
  <el-color-picker
    v-model="theme"
    :predefine="['#409EFF', '#1890ff', '#304156','#212121','#11a983', '#13c2c2', '#6959CD', '#f5222d', ]"
    class="theme-picker"
    popper-class="theme-picker-dropdown"
  />
</template>

<script>
const version = require('element-ui/package.json').version // element-ui version from node_modules
const ORIGINAL_THEME = '#409EFF' // default color

export default {
  data() {
    return {
      chalk: '', // content of theme-chalk css
      theme: ''
    }
  },
  computed: {
    defaultTheme() {
      return this.$store.state.settings.theme
    }
  },
  watch: {
    defaultTheme: {
      handler: function(val, oldVal) {
        this.theme = val
      },
      immediate: true
    },
    async theme(val) {
      const oldVal = this.chalk ? this.theme : ORIGINAL_THEME
      if (typeof val !== 'string') return
      const themeCluster = this.getThemeCluster(val.replace('#', ''))
      const originalCluster = this.getThemeCluster(oldVal.replace('#', ''))
      console.log(themeCluster, originalCluster)

      const $message = this.$message({
        message: '  Compiling the theme',
        customClass: 'theme-message',
        type: 'success',
        duration: 0,
        iconClass: 'el-icon-loading'
      })

      const getHandler = (variable, id) => {
        return () => {
          const originalCluster = this.getThemeCluster(ORIGINAL_THEME.replace('#', ''))
          const newStyle = this.updateStyle(this[variable], originalCluster, themeCluster)

          let styleTag = document.getElementById(id)
          if (!styleTag) {
            styleTag = document.createElement('style')
            styleTag.setAttribute('id', id)
            document.head.appendChild(styleTag)
          }
          styleTag.innerText = newStyle
        }
      }

      if (!this.chalk) {
        const url = `https://unpkg.com/element-ui@${version}/lib/theme-chalk/index.css`
        await this.getCSSString(url, 'chalk')
      }

      const chalkHandler = getHandler('chalk', 'chalk-style')

      chalkHandler()

      const styles = [].slice.call(document.querySelectorAll('style'))
        .filter(style => {
          const text = style.innerText
          return new RegExp(oldVal, 'i').test(text) && !/Chalk Variables/.test(text)
        })
      styles.forEach(style => {
        const { innerText } = style
        if (typeof innerText !== 'string') return
        style.innerText = this.updateStyle(innerText, originalCluster, themeCluster)
      })

      this.$emit('change', val)

      $message.close()
    }
  },

  methods: {
    updateStyle(style, oldCluster, newCluster) {
      let newStyle = style
      oldCluster.forEach((color, index) => {
        newStyle = newStyle.replace(new RegExp(color, 'ig'), newCluster[index])
      })
      return newStyle
    },

    getCSSString(url, variable) {
      return new Promise(resolve => {
        const xhr = new XMLHttpRequest()
        xhr.onreadystatechange = () => {
          if (xhr.readyState === 4 && xhr.status === 200) {
            this[variable] = xhr.responseText.replace(/@font-face{[^}]+}/, '')
            resolve()
          }
        }
        xhr.open('GET', url)
        xhr.send()
      })
    },

    getThemeCluster(theme) {
      const tintColor = (color, tint) => {
        let red = parseInt(color.slice(0, 2), 16)
        let green = parseInt(color.slice(2, 4), 16)
        let blue = parseInt(color.slice(4, 6), 16)

        if (tint === 0) { // when primary color is in its rgb space
          return [red, green, blue].join(',')
        } else {
          red += Math.round(tint * (255 - red))
          green += Math.round(tint * (255 - green))
          blue += Math.round(tint * (255 - blue))

          red = red.toString(16)
          green = green.toString(16)
          blue = blue.toString(16)

          return `#${red}${green}${blue}`
        }
      }

      const shadeColor = (color, shade) => {
        let red = parseInt(color.slice(0, 2), 16)
        let green = parseInt(color.slice(2, 4), 16)
        let blue = parseInt(color.slice(4, 6), 16)

        red = Math.round((1 - shade) * red)
        green = Math.round((1 - shade) * green)
        blue = Math.round((1 - shade) * blue)

        red = red.toString(16)
        green = green.toString(16)
        blue = blue.toString(16)

        return `#${red}${green}${blue}`
      }

      const clusters = [theme]
      for (let i = 0; i <= 9; i++) {
        clusters.push(tintColor(theme, Number((i / 10).toFixed(2))))
      }
      clusters.push(shadeColor(theme, 0.1))
      return clusters
    }
  }
}
</script>

<style>
.theme-message,
.theme-picker-dropdown {
  z-index: 99999 !important;
}

.theme-picker .el-color-picker__trigger {
  height: 26px !important;
  width: 26px !important;
  padding: 2px;
}

.theme-picker-dropdown .el-color-dropdown__link-btn {
  display: none;
}
</style>

该组件将选择到颜色保存到vuex的state中, 代码: "this.$store.state.settings.theme"

2.添加store/modules/setting.js文件

import variables from '@/styles/element-variables.scss'

const state = {
  theme: variables.theme
}

const mutations = {
  CHANGE_SETTING: (state, { key, value }) => {
    if (state.hasOwnProperty(key)) {
      state[key] = value
    }
  }
}

const actions = {
  changeSetting({ commit }, data) {
    commit('CHANGE_SETTING', data)
  }
}

export default {
  namespaced: true,
  state,
  mutations,
  actions
}

setting.js中默认主题是引入的'@/styles/element-variables.scss'

3. 添加element-variables.scss

/**
* I think element-ui's default theme color is too light for long-term use.
* So I modified the default color and you can modify it to your liking.
**/

/* theme color */
$--color-primary: #1890ff;
$--color-success: #13ce66;
$--color-warning: #FFBA00;
$--color-danger: #ff4949;
// $--color-info: #1E1E1E;

$--button-font-weight: 400;

// $--color-text-regular: #1f2d3d;

$--border-color-light: #dfe4ed;
$--border-color-lighter: #e6ebf5;

$--table-border:1px solid#dfe6ec;

/* icon font path, required */
$--font-path: '~element-ui/lib/theme-chalk/fonts';

@import "~element-ui/packages/theme-chalk/src/index";

// the :export directive is the magic sauce for webpack
// https://www.bluematador.com/blog/how-to-share-variables-between-js-and-sass
:export {
  theme: $--color-primary;
}

element-variables.scss 文件通过:export将theme导出,这样就能像使用js变量一样使用scss变量了, 准备工作就绪,开始测试

4.添加测试代码

<template>
  <!-- 添加全局样式 -->
  <div>
    <div>
      <div class="test-theme">
        <el-button type="primary" />
      </div>
      <br>
      <theme-picker style="float: right;height: 26px;margin: -3px 8px 0 0;" @change="themeChange" />
    </div>
  </div>
</template>
<script>
import ThemePicker from '@/components/ThemePicker'
export default {
  name: 'App',
  components: {
    ThemePicker
  },
  data() {
    return {
      msg: 'Dynamic Themes',
      theme: 'default',
    }
  },
  methods: {
    themeChange(val) {
      this.$store.dispatch('settings/changeSetting', {
        key: 'theme',
        value: val
      })
    }
  }
}

大功告成!

优点: 可以动态改变主色调缺点: 没有足够的个性化,仅仅能修改一些基本的配色