taro中textarea组件存在的两个问题：

1. 由于层级过高导致文字穿透，解决办法如下，组件本质还是使用“替代元素”；
2. 在ios机型下输入内容后，ios距离文本框边距较大

import Taro, { useState } from '@tarojs/taro'
import { View, Text, Textarea } from '@tarojs/components'
import classnames from 'classnames'
//获取机型
const { platform = null } = Taro.getSystemInfoSync()


export default function SimulationTextarea ({ value, maxlength, placeholder, autoFocus, onBlur, onTextarea }) {
  const [myValue, setMyValue] = useState(value)
  const [isShowTextarea, setIsShowTextarea] = useState(false)
  const [isAutoFocus, setIsAutoFocus] = useState(autoFocus)

  const onSimulationClick = () => {
    setIsShowTextarea(true)
    setIsAutoFocus(true)
  }

  const onTextareaBlur = (e) => {
    setIsShowTextarea(false)
    setIsAutoFocus(false)
    onBlur(e)
  }

  const onTextareaInput = (e) => {
    setMyValue(e.detail.value)
    onTextarea(e.detail.value)
  }

  return (
    //设置ios下的样式“simulation-textarea-ios”
    <View className={classnames('simulation-textarea', {'simulation-textarea-ios': platform === 'ios'})}  onClick={onSimulationClick}>
      {
        isShowTextarea 
        ?
        <Textarea 
          className='simulation-textarea__textarea simulation-textarea-native'
          value={myValue}
          maxlength={maxlength} 
          placeholder={placeholder}
          autoFocus={isAutoFocus}
          onBlur={onTextareaBlur}
          onInput={onTextareaInput}
          cursor-spacing={50}
          placeholder-style='fontSize: 28px; color: #D8D8D8'
        />
        :
        <View className={classnames('simulation-textarea__textarea simulation-textarea-shadow', {'simulation-textarea-placeholder': !myValue})}>
          <Text decode={1}>{myValue !== '' ? myValue : placeholder}</Text>
        </View>
      }
      {
        maxlength === '-1'
        ?
        null
        :
        <View className='simulation-textarea-count'>({myValue.length}/{maxlength})</View>
      }
    </View>
  )
}

SimulationTextarea.options = {
  addGlobalClass: true
}

SimulationTextarea.defaultProps = {
  maxlength: '-1',
  placeholder: '请输入内容',
  value: '',
  autoFocus: false,
  onBlur () {},
  onTextarea () {},
}