Element-UI源码阅读-button

button用法

<el-button>默认按钮</el-button> 

<el-button type="primary">主要按钮</el-button>

<el-button type="success">成功按钮</el-button> 

<el-button type="info">信息按钮</el-button> 

<el-button type="warning">警告按钮</el-button> 

<el-button type="danger">危险按钮</el-button> 

源码-template

<template>
  // 使用了原生的button
  <button
    class="el-button"
    @click="handleClick"   //this.$emit('click') 父容器可以监听el-button的点击事件
    :disabled="buttonDisabled || loading"
    :autofocus="autofocus"
    :type="nativeType"
     // 绑定el-button提供的按钮样式class vue基本语法
    :class="[
      type ? 'el-button--' + type : '',
      buttonSize ? 'el-button--' + buttonSize : '',
      {
        'is-disabled': buttonDisabled,
        'is-loading': loading,
        'is-plain': plain,
        'is-round': round,
        'is-circle': circle
      }
    ]"
  >
    // 此元素用来显示按钮上的菊花按钮
    // el-icon-loading实际上是element-ui中所有基于类名设置icon的一种方式，el-icon-loading:before {content: '\xxxx'} xxxx图片的实际编码，存储在font文件下的.ttf和.woff文件中。
    // 所有基于class的icon设置可以见theme-chalk下的icon.scss
    <i class="el-icon-loading" v-if="loading"></i>
    // 是否显示icon
    <i :class="icon" v-if="icon && !loading"></i>
    // 是否显示默认插槽
    <span v-if="$slots.default"><slot></slot></span>
  </button>
</template>

源码-script

<script>
  export default {
    name: 'ElButton',

    inject: {
      elForm: {
        default: ''
      },
      elFormItem: {
        default: ''
      }
    },
    
    // 没什么难点,一看就懂
    props: {
      type: {
        type: String,
        default: 'default'
      },
      size: String,
      icon: {
        type: String,
        default: ''
      },
      nativeType: {
        type: String,
        default: 'button'
      },
      loading: Boolean,
      disabled: Boolean,
      plain: Boolean,
      autofocus: Boolean,
      round: Boolean,
      circle: Boolean
    },

    computed: {
      _elFormItemSize() {
        return (this.elFormItem || {}).elFormItemSize;
      },
      buttonSize() {
        return this.size || this._elFormItemSize || (this.$ELEMENT || {}).size;
      },
      buttonDisabled() {
        return this.$options.propsData.hasOwnProperty('disabled') ? this.disabled : (this.elForm || {}).disabled;
      }
    },

    methods: {
      handleClick(evt) {
        this.$emit('click', evt);
      }
    }
  };
</script>

源码-style

@charset "UTF-8";
@import "common/var";   //整个框架使用到的常量都定义在这里
@import "mixins/button"; // 一下三个是使用sass构建的样式工具代码
@import "mixins/mixins";
@import "mixins/utils";

@include b(button) {
  display: inline-block;
  line-height: 1;
  white-space: nowrap;
  cursor: pointer;
  background: $--button-default-background-color;
  border: $--border-base;
  border-color: $--button-default-border-color;
  color: $--button-default-font-color;
  -webkit-appearance: none;
  text-align: center;
  box-sizing: border-box;
  outline: none;
  margin: 0;
  transition: .1s;
  font-weight: $--button-font-weight;
  @include utils-user-select(none);   // button上的内容内容禁止选中
  & + & {
    margin-left: 10px;
  }
  //  设置button的大小
  @include button-size($--button-padding-vertical, $--button-padding-horizontal, $--button-font-size, $--button-border-radius);

// 根据鼠标行为设置按钮样式主要是背景色，字体颜色和边框颜色
  &:hover,
  &:focus {
    color: $--color-primary;
    border-color: $--color-primary-light-7;
    background-color: $--color-primary-light-9;
  }

  &:active {
    color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
    border-color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
    outline: none;
  }

   //  在Firefox上outline：none可能失效，可以使用-moz-focus-inner兼容
  &::-moz-focus-inner {
    border: 0;
  }

  & [class*="el-icon-"] {
    & + span {
      margin-left: 5px;
    }
  }
// 这部分都是常规样式设置
  @include when(plain) {
    &:hover,
    &:focus {
      background: $--color-white;
      border-color: $--color-primary;
      color: $--color-primary;
    }

    &:active {
      background: $--color-white;
      border-color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
      color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
      outline: none;
    }
  }

  @include when(active) {
    color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
    border-color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
  }

  @include when(disabled) {
    &,
    &:hover,
    &:focus {
      color: $--button-disabled-font-color;
      cursor: not-allowed;
      background-image: none;
      background-color: $--button-disabled-background-color;
      border-color: $--button-disabled-border-color;
    }

    &.el-button--text {
      background-color: transparent;
    }

    &.is-plain {
      &,
      &:hover,
      &:focus {
        background-color: $--color-white;
        border-color: $--button-disabled-border-color;
        color: $--button-disabled-font-color;
      }
    }
  }

// 显示带有菊花加载样式的按钮，使用伪元素实现
  @include when(loading) {
    position: relative;
    pointer-events: none;

    &:before {
      pointer-events: none; // 禁止鼠标事件
      content: '';
      position: absolute;
      left: -1px;
      top: -1px;
      right: -1px;
      bottom: -1px;
      border-radius: inherit;
      background-color: rgba(255,255,255,.35);
    }
  }
  // 以下是不同类型的按钮样式
  @include when(round) {
    border-radius: 20px;
    padding: 12px 23px;
  }
  @include when(circle) {
    border-radius: 50%;
    padding: $--button-padding-vertical;
  }
  @include m(primary) {
    @include button-variant($--button-primary-font-color, $--button-primary-background-color, $--button-primary-border-color);
  }
  @include m(success) {
    @include button-variant($--button-success-font-color, $--button-success-background-color, $--button-success-border-color);
  }
  @include m(warning) {
    @include button-variant($--button-warning-font-color, $--button-warning-background-color, $--button-warning-border-color);
  }
  @include m(danger) {
    @include button-variant($--button-danger-font-color, $--button-danger-background-color, $--button-danger-border-color);
  }
  @include m(info) {
    @include button-variant($--button-info-font-color, $--button-info-background-color, $--button-info-border-color);
  }
  @include m(medium) {
    @include button-size($--button-medium-padding-vertical, $--button-medium-padding-horizontal, $--button-medium-font-size, $--button-medium-border-radius);
    @include when(circle) {
      padding: $--button-medium-padding-vertical;
    }
  }
  @include m(small) {
    @include button-size($--button-small-padding-vertical, $--button-small-padding-horizontal, $--button-small-font-size, $--button-small-border-radius);
    @include when(circle) {
      padding: $--button-small-padding-vertical;
    }
  }
  @include m(mini) {
    @include button-size($--button-mini-padding-vertical, $--button-mini-padding-horizontal, $--button-mini-font-size, $--button-mini-border-radius);
    @include when(circle) {
      padding: $--button-mini-padding-vertical;
    }
  }
  @include m(text) {
    border-color: transparent;
    color: $--color-primary;
    background: transparent;
    padding-left: 0;
    padding-right: 0;

    &:hover,
    &:focus {
      color: mix($--color-white, $--color-primary, $--button-hover-tint-percent);
      border-color: transparent;
      background-color: transparent;
    }
    &:active {
      color: mix($--color-black, $--color-primary, $--button-active-shade-percent);
      border-color: transparent;
      background-color: transparent;
    }

    &.is-disabled,
    &.is-disabled:hover,
    &.is-disabled:focus {
      border-color: transparent;
    }
  }
}

// 按钮组的样式设置
@include b(button-group) {
  @include utils-clearfix;
  display: inline-block;
  vertical-align: middle;

  & > .el-button {
    float: left;
    position: relative;
    & + .el-button {
      margin-left: 0;
    }
    &.is-disabled {
      z-index: 1;
    }
    &:first-child {
      border-top-right-radius: 0;
      border-bottom-right-radius: 0;
    }
    &:last-child {
      border-top-left-radius: 0;
      border-bottom-left-radius: 0;
    }
    &:first-child:last-child {
      border-top-right-radius: $--button-border-radius;
      border-bottom-right-radius: $--button-border-radius;
      border-top-left-radius: $--button-border-radius;
      border-bottom-left-radius: $--button-border-radius;

      &.is-round {
        border-radius: 20px;
      }

      &.is-circle {
        border-radius: 50%;
      }
    }
    &:not(:first-child):not(:last-child) {
      border-radius: 0;
    }
    &:not(:last-child) {
      margin-right: -1px;
    }

    &:not(.is-disabled) {
      &:hover,
      &:focus,
      &:active {
        z-index: 1;
      }
    }

    @include when(active) {
      z-index: 1;
    }
  }
  
  & > .el-dropdown {
    & > .el-button {
      border-top-left-radius: 0;
      border-bottom-left-radius: 0;
      border-left-color: rgba($--color-white, 0.5);
    }
  }

  @each $type in (primary, success, warning, danger, info) {
    .el-button--#{$type} {
      &:first-child {
        border-right-color: rgba($--color-white, 0.5);
      }
      &:last-child {
        border-left-color: rgba($--color-white, 0.5);
      }
      &:not(:first-child):not(:last-child) {
        border-left-color: rgba($--color-white, 0.5);
        border-right-color: rgba($--color-white, 0.5);
      }
    }
  }
}

总结:

1.template和script部分是比较简单的，复杂的地方在style部分

2.在按钮添加icon时单独使用了i元素进行定位显示而不是使用class，这个设计思想可以在项目中借鉴。

2.大量的使用了sass预处理样式，所以看懂整个框架sass是必须要了解的

下一章节：

Element-UI-link（未完待续）