如何仅在reactnative的底部设置高程阴影

发布于02月13日

我试图在视图底部添加阴影，但我不知道如何在Android上实现.elevation的时候，它会在顶部加上一个阴影.有没有办法在iOS上做到这一点？

这是我的代码:

export function makeElevation(elevation) {
const iosShadowElevation = {
    shadowOpacity: 0.0015 * elevation + 0.18,
    shadowRadius: 0.5 * elevation,
    shadowOffset: {
        height: 0.6 * elevation,
    },
};
const androidShadowElevation = {
    elevation,
};
return Platform.OS === 'ios' ? iosShadowElevation : androidShadowElevation;

}

左:iOS(预期)

右:安卓

编辑:我发现的唯一"假"解决方案是使用react-native-linear-gradient来创建自定义阴影.

推荐答案

You can use overflow: 'hidden' to achieve the desired result without having to install a library.
wrap the view in a parent view and set the parent's overflow to hidden and apply a padding only on the side where you want your shadow to appear like so:

  <View style={{ overflow: 'hidden', paddingBottom: 5 }}>
    <View
      style={{
        backgroundColor: '#fff',
        width: 300,
        height: 60,
        shadowColor: '#000',
        shadowOffset: { width: 1, height: 1 },
        shadowOpacity:  0.4,
        shadowRadius: 3,
        elevation: 5,
      }} 
    />
  </View>

结果:

here's a custom component that you can use:

import React from 'react'
import { View, StyleSheet, ViewPropTypes } from 'react-native'
import PropTypes from 'prop-types'


const SingleSidedShadowBox = ({ children, style }) => (
  <View style={[ styles.container, style ]}>
    { children }
  </View>
);

const styles = StyleSheet.create({
  container:{
    overflow: 'hidden',
    paddingBottom: 5,
  }
});

SingleSidedShadowBox.propTypes = {
  children: PropTypes.element,
  style: ViewPropTypes.style,
};

export default SingleSidedShadowBox;

example:

<SingleSidedShadowBox style={{width: '90%', height: 40}}>
  <View style={{
    backgroundColor: '#fff',
    width: '100%',
    height: '100%',
    shadowColor: '#000',
    shadowOffset: { width: 1, height: 1 },
    shadowOpacity:  0.4,
    shadowRadius: 3,
    elevation: 5,
  }} />
</SingleSidedShadowBox>

你可以根据你的阴影来调整填充