微信小程序 textarea 层级过高的解决方式

建立一个新的textarea 组件代替原生textarea ,废话不多说,上代码

<template>
    <view class="ui-textarea">
        <textarea class="textarea {{ hide? 'hidden':''}}" auto-height maxlength="{{maxlength}}" name="{{ name }}" value="{{ txt }}" placeholder="{{ placeholder }}" bindinput="onInput" bindblur="onBlur" focus="{{focus}}"></textarea>
        <view hidden="{{ hide == false }}" class="{{ txt === ''?'text placeholder':'text'}}" bindtap="onFocus">{{ txt ===''? placeholder:txt }}</view>
    </view>
</template>
<script>
export default {
    config: {
        usingComponents: {}
    },
    behaviors: [],
    properties: {
        placeholder: {
            type: String,
            value: ''
        },
        maxlength: {
            type: Number,
            value: 128
        },
        name: String,
        value: {
            type: String,
            value: ''
        }
    },
    data: {
        hide: true,
        txt: '',
        focus: false
    },
    ready() {
        if (this.data.value != '') {
            this.setData({ txt: this.data.value })
        }
    },
    methods: {
        onFocus() {
            this.setData({ hide: false, focus: true })
        },
        onInput(e) {
            this.setData({ txt: e.detail.value })
        },
        onBlur() {
            this.setData({ hide: true, focus: false })
        }
    }
}
</script>
<style lang="less">
.ui-textarea {
  position: relative !important;

  .textarea.hidden {
    display: block !important;
    position: absolute !important;
    left: -999px;
    right: -999px;
    top: 0;
  }

  .textarea {
    width: 100%;
    box-sizing: border-box;
  }

  .text {
    height: 100%;
    padding: 6px 5px;
    font-size: 14px;
  }

  .placeholder {
    color: #888;
  }
}
</style>

Vue 代码,自己根据需求改一下 ,特别注意,不要用 wx;if 或者 hidden 属性 , wx:if 频繁渲染,虽然可以用,hidden 会出现 部分显示bug,[hidden]  会使auto-height 首次不正确