微信小程序 textarea 层级过高问题简单解决方案

<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>