uni-app微信小程序——下拉多选框

插件来自：select-cy - DCloud 插件市场

1、组件代码

<template>
  <view class="uni-select-cy" :style="{ 'z-index': zindex }">
    <view class="uni-select-cy-select" :class="{ active: active }" @click.stop="handleSelect">
      <!-- 禁用mask -->
      <view class="uni-disabled" v-if="disabled"></view>
      <!-- 清空 -->
      <view class="close-icon close-postion" v-if="realValue.length && !active && !disabled && showClearIcon">
        <text @click.stop="handleRemove(null)"></text>
      </view>
      <!-- 显示框 -->
      <view class="uni-select-multiple" v-show="realValue.length">
        <view class="uni-select-multiple-item" v-for="(item, index) in realValue" :key="index">
          {
   { item }}
          <view class="close-icon" v-if="showValueClear"><text @click.stop="handleRemove(index)"></text> </view>
        </view>
      </view>
      <!-- 为空时的显示文案 -->
      <view v-if="realValue.length == 0 && showplaceholder">{
   { placeholder }}</view>
      <!-- 禁用图标 -->
      <view class="uni-select-cy-icon" :class="{ disabled: disabled }"><text></text></view>
    </view>
    <!-- 下拉选项 -->
    <scroll-view class="uni-select-cy-options" :scroll-y="true" v-show="active">
      <template>
        <view
          class="uni-select-cy-item"
          :class="{ active: realValue.includes(item[svalue]) }"
          v-for="(item, index) in options"
          :key="index"
          @click.stop="handleChange(index, item)"
        >
          {
   { item[slabel] }}
        </view>
      </template>
    </scroll-view>
  </view>
</template>

<script>
export default {
  name: 'select-cy',
  props: {
    // 是否显示全部清空按钮
    showClearIcon: {
      type: Boolean,
      default: false,
    },
    // 是否显示单个删除
    showValueClear: {
      type: Boolean,
      default: true,
    },
    zindex: {
      type: Number,
      default: 999,
    },
    // 禁用组件
    disabled: {
      type: Boolean,
      default: false,
    },
    options: {
      type: Array,
      default() {
        return [];
      },
    },
    value: {
      type: Array,
      default() {
        return [];
      },
    },
    placeholder: {
      type: String,
      default: '请选择',
    },
    showplaceholder: {
      type: Boolean,
      default: true,
    },
    slabel: {
      type: String,
      default: 'text',
    },
    svalue: {
      type: String,
      default: 'value',
    },
  },
  data() {
    return {
      active: false, // 组件是否激活，
      changevalue: [], // 搜索框同步
      realValue: [],
    };
  },
  mounted() {
    // 初始化
    this.init();
  },
  methods: {
    close() {
      this.active = false;
    },
    init() {
      if (this.value.length > 0) {
        this.changevalue = this.options.forEach((item) => {
          this.value.forEach((i) => {
            if (item[this.svalue] === i[this.svalue]) {
              return item;
            }
          });
        });
        this.realValue = this.value;
      } else {
        this.changevalue = [];
        this.realValue = [];
      }
    },
    // 点击展示选项
    handleSelect() {
      if (this.disabled) return;
      this.active = !this.active;
    },
    // 移除数据
    handleRemove(index) {
      if (index === null) {
        this.realValue = [];
        this.changevalue = [];
      } else {
        this.realValue.splice(index, 1);
        this.changevalue.splice(index, 1);
      }
      this.$emit('change', this.changevalue, this.realValue);
    },
    // 点击组件列
    handleChange(index, item) {
      const arrIndex = this.realValue.indexOf(item[this.svalue]);
      if (arrIndex > -1) {
        this.changevalue.splice(arrIndex, 1);
        this.realValue.splice(arrIndex, 1);
      } else {
        this.changevalue.push(item);
        this.realValue.push(item[this.svalue]);
      }
      console.log(this.realValue, 'this.realValue');
      this.$emit('change', this.changevalue, this.realValue);
    },
  },
};
</script>

<style lang="scss" scoped>
.uni-select-cy {
  position: relative;
  z-index: 999;

  .uni-select-mask {
    width: 100%;
    height: 100%;
  }

  /* 删除按钮样式*/
  .close-icon {
    height: 100%;
    width: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 3;
    cursor: pointer;

    text {
      position: relative;
      background: #c0c4cc;
      width: 13px;
      height: 13px;
      border-radius: 50%;
      border: 1px solid #bbb;

      &::before,
      &::after {
        content: '';
        position: absolute;
        left: 20%;
        top: 50%;
        height: 1px;
        width: 60%;
        transform: rotate(45deg);
        background-color: #909399;
      }

      &::after {
        transform: rotate(-45deg);
      }
    }
  }

  //所有情空的定位
  .close-postion {
    position: absolute;
    right: 35px;
    top: 0;
    height: 100%;
    width: 15px;
  }

  /* 多选盒子 */
  .uni-select-multiple {
    overflow-x: auto;
    display: flex;

    .uni-select-multiple-item {
      background: #f4f4f5;
      margin-right: 5px;
      padding: 2px 4px;
      border-radius: 4px;
      color: #909399;
      display: flex;
    }
  }

  // select部分
  .uni-select-cy-select {
    user-select: none;
    position: relative;
    z-index: 3;
    height: 36px;
    padding: 0 30px 0 10px;
    box-sizing: border-box;
    border-radius: 4px;
    border: 1px solid rgb(229, 229, 229);
    display: flex;
    align-items: center;
    font-size: 14px;
    color: #999;

    .uni-disabled {
      position: absolute;
      left: 0;
      width: 100%;
      height: 100%;
      z-index: 19;
      cursor: no-drop;
      background: rgba(255, 255, 255, 0.5);
    }

    .uni-select-cy-input {
      font-size: 14px;
      color: #999;
      display: block;
      width: 96%;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
      line-height: 30px;
      box-sizing: border-box;

      &.active {
        color: #333;
      }
    }

    .uni-select-cy-icon {
      cursor: pointer;
      position: absolute;
      right: 0;
      top: 0;
      height: 100%;
      width: 30px;
      display: flex;
      align-items: center;
      justify-content: center;

      &::before {
        content: '';
        width: 1px;
        height: 100%;
        position: absolute;
        left: 0;
        top: 0;
        background-color: #e5e5e5;
      }

      text {
        display: block;
        width: 0;
        height: 0;
        border-width: 12rpx 12rpx 0;
        border-style: solid;
        border-color: #bbb transparent transparent;
        transition: 0.3s;
      }

      &.disabled {
        cursor: no-drop;

        text {
          width: 20rpx;
          height: 20rpx;
          border: 2px solid #ff0000;
          border-radius: 50%;
          transition: 0.3s;
          position: relative;
          z-index: 999;

          &::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 0;
            width: 100%;
            height: 2px;
            margin-top: -1px;
            background-color: #ff0000;
            transform: rotate(45deg);
          }
        }
      }
    }

    &.active .uni-select-cy-icon {
      text {
        transform: rotate(180deg);
      }
    }
  }

  // options部分
  .uni-select-cy-options {
    user-select: none;
    position: absolute;
    top: calc(100% + 5px);
    left: 0;
    width: 100%;
    height: 500rpx;
    border-radius: 4px;
    border: 1px solid rgb(229, 229, 229);
    background: #fff;
    padding: 5px 0;
    box-sizing: border-box;
    z-index: 9;

    .uni-select-cy-item {
      padding: 0 10px;
      box-sizing: border-box;
      cursor: pointer;
      line-height: 2.5;
      transition: 0.3s;
      font-size: 14px;

      &.active {
        color: #409eff;

        background-color: #f5f7fa &hover {
          color: #409eff;
          background-color: #f5f7fa;
        }
      }

      &:hover {
        background-color: #f5f5f5;
      }
    }
  }
}
</style>

2、使用说明

## 插件使用方法：

`<select-lay :value="tval" name="name" :options="datalist" @selectitem="selectitem"></select-lay>`

## 配置参数：

|     属性名      |  类型   | 默认值 | 说明                                             |
| :-------------: | :-----: | :----: | ------------------------------------------------ |
|  showClearIcon  | Boolean | false  | 是否显示全部清空按钮                             |
| showValueClear  | Boolean |  true  | 是否显示单个删除                                 |
|     zindex      | Number  |   ""   | 层级，默认 999，防止多个组件一起使用时下拉栏穿透 |
|     slabel      | String  |  text  | 自定义列表中键值对关系，参考示例                 |
|     svalue      | String  | value  | 自定义列表中键值对关系，该值对应 value，参考示例 |
|   placeholder   | String  | 请选择 | 无选项时展示的文字                               |
| showplaceholder | Boolean |  true  | 下拉时是否展示请选择按钮                         |
|     options     |  Array  |   无   | 数据列表                                         |
|    disabled     | Boolean | false  | 是否禁用                                         |
|      value      |  Array  |   无   | 选中值及回显                                     |

## 事件：

| 事件名  |            说明            | 返回值                              |
| :-----: | :------------------------: | ----------------------------------- |
| @change | 点击项目或者删除触发的事件 | 返回全量选中项及只有 value 的选中项 |

## 说明：

此插件依赖 scss，请务必安装！！！

## 示例：

```
	<template>
		<view class="content">
			<form @submit="formSubmit">
				<view class="item">写法：</view>
				<select-cy :value="tval" placeholder="请选择项目" :options="datalist" @change="change"></select-cy>
				<select-cy :value="tval" placeholder="请选择项目1" :options="datalist" @change="change"></select-cy>
				<button type="submit" @click="formSubmit">提交</button>
			</form>
		</view>
	</template>

	<script>
	export default {
		data() {
			return {
				//模拟数据列表
				datalist: [],
				//模拟初始数据
				tval: []
			};
		},
		onReady() {
			this.datalist = [
				{
					label: 'label1',
					value: 'value1'
				},
				{
					label: 'label2',
					value: 'value2'
				},
				{
					label: 'label3',
					value: 'value3'
				},
				{
					label: 'label4',
					value: 'value4'
				},
				{
					label: 'label5',
					value: 'value5'
				},
				{
					label: 'label6',
					value: 'value6'
				},
				{
					label: 'label7',
					value: 'value7'
				},
				{
					label: 'label8',
					value: 'value8'
				},
				{
					label: 'label9',
					value: 'value9'
				}
			];
		},
		methods: {
			formSubmit(e) {
				console.log(this.tval,'提交参数');
			},
			change(item,value) {
				console.log(item,value);
				this.tval = value;
			}
		}
	};
	</script>

	<style lang="scss">
	.content {
		width: 300px;
		padding: 20px 0;
		margin: 0 auto;

		.item {
			margin-bottom: 10px;
		}

		.btn {
			margin-top: 20px;
		}
	}
	</style>


```