Vue造轮子-手风琴组件-原创手记-慕课网

一. 大致的使用方法

<div id="app" style="padding-left: 100px">
  <g-collpase>
    <g-collapse-item title="标题1">内容1</g-collapse-item>
    <g-collapse-item title="标题2">内容2</g-collapse-item>
    <g-collapse-item title="标题3">内容3</g-collapse-item>
  </g-collpase>
</div>

二. 完成最外部的样式

//collapse
<style lang="scss" scoped>
  $grey: #ddd;
  $border-radius: 4px;
  .collapse {
    border: 1px solid $grey;
    border-radius: $border-radius;
  }
</style>

//collapse-item.vue
<style lang="scss" scoped>
  $grey: #ddd;
  $border-radius: 4px;
  .collapseItem {
    > .title {
      border: 1px solid $grey;
      margin-top: -1px;
      margin-left: -1px;
      margin-right: -1px;
    }
    &:first-child {
      > .title {
        border-top-left-radius: $border-radius;
        border-top-right-radius: $border-radius;
      }
    }
  }
</style>

三. 进一步调节样式

// collapse-item
<style lang="scss" scoped>
  $grey: #ddd;
  $border-radius: 4px;
  .collapseItem {
    > .title {
      border: 1px solid $grey;
      margin-top: -1px;
      margin-left: -1px;
      margin-right: -1px;
      min-height: 32px;
      display: flex;
      align-items: center;
      padding: 0 8px;
    }
    &:first-child {
      > .title {
        border-top-left-radius: $border-radius;
        border-top-right-radius: $border-radius;
      }
    }
    > .content{
      padding: 8px;
    }
  }
</style>

四. 默认内容折叠起来和点击切换，基本样式和基本功能完成

// collapse-item
    data (){
      return {
        open: false
      }
    }

    <div class="content" v-if="open" @click="open=!open">
      <slot></slot>
    </div>

五. 完善功能第一个点开,第二个就关闭

因为结构比较简单，就父子两个组件，可以用父子通信来做。

    mounted(){
      this.eventBus.$on('update:selected', (vm)=>{
        if (vm !== this){
          this.close()
        }
      })
    },
    methods:{
      toggle(){
        if(this.open) {
          this.open = false
        }else{
          this.open = true
          this.eventBus.$emit('update:selected', this)
        }
      },
      close(){
        this.close()
      }
    }

六. 增加功能是否可以选择多个

方案一.用 single 变量是否需要控制 eventBus

    // 添加single选项,有single就注入，没有就不注入
    // 但是这种方式不太完美会有警告
    props: {
      single: {
        type: Boolean,
        default: false
      }
    },
    provide() {
      if(this.single){
        return {
          eventBus: this.eventBus
        }
      }
    }

七. 可以设置默认 selected

// index.html

    <div id="app" style="padding: 100px">
      <g-collapse selected="2">
        <g-collapse-item title="标题1" name="1">内容1</g-collapse-item>
        <g-collapse-item title="标题2" name="2">内容2</g-collapse-item>
        <g-collapse-Item title="标题3" name="3">内容3</g-collapse-Item>
      </g-collapse>
    </div>

// collapse-item.vue
    mounted(){
      this.eventBus && this.eventBus.$on('update:selected', (name)=>{
        if (name !== this.name){
          this.close()
        }else{
          this.show()
        }
      })
    },

八. 回头解决子元素是否可以多个打开

通过 collapse.vue 传给 collapse-item

// index.js
  <div id="app" style="padding: 100px">
    <g-collapse :selected="selectedTab" :selected.sync="selectedTab" single>
      <g-collapse-item title="标题1" name="1">内容1 Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusamus consequatur </g-collapse-item>
      <g-collapse-item title="标题2" name="2">内容2 Lorem ipsum dolor sit amet, consectetur adipisicing elit. Aliquid cupiditate dolore d! </g-collapse-item>
      <g-collapse-Item title="标题3" name="3"> 内容3 Lorem ipsum dolor sit amet, consectetur adipisicing elit. Excepturi, magnam. </g-collapse-Item>
      {{selectedTab}}
    </g-collapse>
  </div>
// collapse.vue
 mounted(){
      this.eventBus.$emit('update:selected',this.selected)
      this.eventBus.$on('update:selected', (name)=>{
        this.$emit('update:selected',name)
      })
      this.$children.forEach((vm)=>{
        vm.single = this.single
        console.log(vm)
      })
    }
// collapse-item.vue
  mounted(){
      this.eventBus && this.eventBus.$on('update:selected', (name)=>{
        if (name !== this.name){
          if(this.single){
            this.close()
          }
        }else{
          this.show()
        }
      })
    },

9.进一步修改，把选中的值改为数组

    // collapse.vue
    mounted(){
      this.eventBus.$emit('update:selected',this.selected)
      this.eventBus.$on('update:addSelected', (name)=>{
        this.selected.push(name)
        this.eventBus.$emit('update:selected',this.selected)  // 通知儿子
        this.$emit('update:selected',this.selected) // 通知外面
      })
      this.eventBus.$on('update:removeSelected', (name)=>{
        let index = this.selected.indexOf(name)
        this.selected.splice(index,1)
        this.eventBus.$emit('update:selected',this.selected)
        this.$emit('update:selected',this.selected)
      })
      this.$children.forEach((vm)=>{
        vm.single = this.single
        console.log(vm)
      })
    }
    // collapse-item.vue
    methods:{
      toggle(){
        if(this.open) {
          this.open = false
          this.eventBus && this.eventBus.$emit('update:removeSelected', this.name)
          // 移除一个被选中的东西
        }else{
          this.eventBus && this.eventBus.$emit('update:addSelected', this.name)
        }
      },
    }

####10. 将所有数据流让父组件统一管理。

不能直接操作 props 要先深拷贝

  // collapse.vue
      mounted(){
      this.eventBus.$emit('update:selected',this.selected)
      this.eventBus.$on('update:addSelected', (name)=>{
        let selectedCopy = JSON.parse(JSON.stringify(this.selected))
        if(this.single){
          selectedCopy = [name]
        }else{
          selectedCopy.push(name)
        }
        this.eventBus.$emit('update:selected',selectedCopy)  // 通知儿子
        this.$emit('update:selected',selectedCopy) // 通知外面
      })
      this.eventBus.$on('update:removeSelected', (name)=>{
        let selectedCopy = JSON.parse(JSON.stringify(this.selected))
        let index = selectedCopy.indexOf(name)
        selectedCopy.splice(index,1)
        this.eventBus.$emit('update:selected',selectedCopy)
        this.$emit('update:selected',selectedCopy)
      })
      this.$children.forEach((vm)=>{
        vm.single = this.single
        console.log(vm)
      })
    }

11. 数据流的核心

不要出现两个东西互相让对方更新的状态

  // collapse.vue 爸爸
      mounted(){
      this.eventBus.$emit('update:selected',this.selected) // 一开始就通知所有儿子，该选中就选中
      this.eventBus.$on('update:addSelected', (name)=>{
        let selectedCopy = JSON.parse(JSON.stringify(this.selected))
        // 如果用户添加一个我就把selected拷贝一份，因为vue不支持直接修改props
        if(this.single){
          selectedCopy = [name]
        }else{
          selectedCopy.push(name)
        }
        this.eventBus.$emit('update:selected',selectedCopy)  // 得到最新被选中的item之后,通知儿子
        this.$emit('update:selected',selectedCopy) // 通知外面
      })

      this.eventBus.$on('update:removeSelected', (name)=>{
        let selectedCopy = JSON.parse(JSON.stringify(this.selected))
        let index = selectedCopy.indexOf(name)
        selectedCopy.splice(index,1)
        this.eventBus.$emit('update:selected',selectedCopy) // 如果用户想移除，也通知他儿子该移除就移除
        this.$emit('update:selected',selectedCopy)
      })
      this.$children.forEach((vm)=>{
        vm.single = this.single
        console.log(vm)
      })
    }¡
    // collapse-item.vue 儿子
        mounted(){
      this.eventBus && this.eventBus.$on('update:selected', (names)=>{
        // 监听eventBus,只要他爸爸要说更新，他就更新
        console.log(names)
        if (names.indexOf(this.name )>= 0){
          this.open = true
        }else{
            this.open = false
        }
      })
    },
    methods:{
      toggle(){
        if(this.open) {
          // 这里也没有修改自己的OPEN，而是在mounted中等爸爸通知我们修改open,所以他的open永远是爸爸在操作，儿子不操作
          this.eventBus &&this.eventBus.$emit('update:removeSelected', this.name)
          // 他自己触发一个意图，打算移除一个更新
          // 移除一个被选中的东西
        }else{
          this.eventBus && this.eventBus.$emit('update:addSelected', this.name)
          // 他自己触发一个意图，打算添加一个更新
        }
      },
    }