| <template> | 
|     <view class="u-dropdown-item" v-if="active" @touchmove.stop.prevent="() => {}" @tap.stop.prevent="() => {}"> | 
|         <block v-if="!$slots.default && !$slots.$default"> | 
|             <scroll-view scroll-y="true" :style="{ | 
|                 height: $u.addUnit(height) | 
|             }"> | 
|                 <view class="u-dropdown-item__options"> | 
|                     <u-cell-group> | 
|                         <u-cell-item @click="cellClick(item.value)" :arrow="false" :title="item.label" v-for="(item, index) in options" | 
|                          :key="index" :title-style="{ | 
|                             color: value == item.value ? activeColor : inactiveColor | 
|                         }"> | 
|                             <u-icon v-if="value == item.value" name="checkbox-mark" :color="activeColor" size="32"></u-icon> | 
|                         </u-cell-item> | 
|                     </u-cell-group> | 
|                 </view> | 
|             </scroll-view> | 
|         </block> | 
|         <slot v-else /> | 
|     </view> | 
| </template> | 
|   | 
| <script> | 
|     /** | 
|      * dropdown-item 下拉菜单 | 
|      * @description 该组件一般用于向下展开菜单,同时可切换多个选项卡的场景 | 
|      * @tutorial http://uviewui.com/components/dropdown.html | 
|      * @property {String | Number} v-model 双向绑定选项卡选择值 | 
|      * @property {String} title 菜单项标题 | 
|      * @property {Array[Object]} options 选项数据,如果传入了默认slot,此参数无效 | 
|      * @property {Boolean} disabled 是否禁用此选项卡(默认false) | 
|      * @property {String | Number} duration 选项卡展开和收起的过渡时间,单位ms(默认300) | 
|      * @property {String | Number} height 弹窗下拉内容的高度(内容超出将会滚动)(默认auto) | 
|      * @example <u-dropdown-item title="标题"></u-dropdown-item> | 
|      */ | 
|     export default { | 
|         name: 'u-dropdown-item', | 
|         props: { | 
|             // 当前选中项的value值 | 
|             value: { | 
|                 type: [Number, String, Array], | 
|                 default: '' | 
|             }, | 
|             // 菜单项标题 | 
|             title: { | 
|                 type: [String, Number], | 
|                 default: '' | 
|             }, | 
|             // 选项数据,如果传入了默认slot,此参数无效 | 
|             options: { | 
|                 type: Array, | 
|                 default () { | 
|                     return [] | 
|                 } | 
|             }, | 
|             // 是否禁用此菜单项 | 
|             disabled: { | 
|                 type: Boolean, | 
|                 default: false | 
|             }, | 
|             // 下拉弹窗的高度 | 
|             height: { | 
|                 type: [Number, String], | 
|                 default: 'auto' | 
|             }, | 
|         }, | 
|         data() { | 
|             return { | 
|                 active: false, // 当前项是否处于展开状态 | 
|                 activeColor: '#2979ff', // 激活时左边文字和右边对勾图标的颜色 | 
|                 inactiveColor: '#606266', // 未激活时左边文字和右边对勾图标的颜色 | 
|             } | 
|         }, | 
|         computed: { | 
|             // 监听props是否发生了变化,有些值需要传递给父组件u-dropdown,无法双向绑定 | 
|             propsChange() { | 
|                 return `${this.title}-${this.disabled}`; | 
|             } | 
|         }, | 
|         watch: { | 
|             propsChange(n) { | 
|                 // 当值变化时,通知父组件重新初始化,让父组件执行每个子组件的init()方法 | 
|                 // 将所有子组件数据重新整理一遍 | 
|                 if (this.parent) this.parent.init(); | 
|             } | 
|         }, | 
|         created() { | 
|             // 父组件的实例 | 
|             this.parent = false; | 
|         }, | 
|         methods: { | 
|             init() { | 
|                 // 获取父组件u-dropdown | 
|                 let parent = this.$u.$parent.call(this, 'u-dropdown'); | 
|                 if (parent) { | 
|                     this.parent = parent; | 
|                     // 将子组件的激活颜色配置为父组件设置的激活和未激活时的颜色 | 
|                     this.activeColor = parent.activeColor; | 
|                     this.inactiveColor = parent.inactiveColor; | 
|                     // 将本组件的this,放入到父组件的children数组中,让父组件可以操作本(子)组件的方法和属性 | 
|                     // push进去前,显判断是否已经存在了本实例,因为在子组件内部数据变化时,会通过父组件重新初始化子组件 | 
|                     let exist = parent.children.find(val => { | 
|                         return this === val; | 
|                     }) | 
|                     if (!exist) parent.children.push(this); | 
|                     if (parent.children.length == 1) this.active = true; | 
|                     // 父组件无法监听children的变化,故将子组件的title,传入父组件的menuList数组中 | 
|                     parent.menuList.push({ | 
|                         title: this.title, | 
|                         disabled: this.disabled | 
|                     }); | 
|                 } | 
|             }, | 
|             // cell被点击 | 
|             cellClick(value) { | 
|                 // 修改通过v-model绑定的值 | 
|                 this.$emit('input', value); | 
|                 // 通知父组件(u-dropdown)收起菜单 | 
|                 this.parent.close(); | 
|                 // 发出事件,抛出当前勾选项的value | 
|                 this.$emit('change', value); | 
|             } | 
|         }, | 
|         mounted() { | 
|             this.init(); | 
|         } | 
|     } | 
| </script> | 
|   | 
| <style scoped lang="scss"> | 
|     @import "../../libs/css/style.components.scss"; | 
| </style> |