问react-native-chart-kit不同阴影颜色

EN

import * as React from 'react';
import { Text, View, StyleSheet } from 'react-native';
import Constants from 'expo-constants';
import {
  LineChart,
  BarChart,
  PieChart,
  ProgressChart,
  ContributionGraph,
  StackedBarChart,
} from 'react-native-chart-kit';
import { Dimensions } from 'react-native';
const screenWidth = Dimensions.get('window').width;
// You can import from local files
import AssetExample from './components/AssetExample';
// or any pure javascript modules available in npm
import { Card } from 'react-native-paper';
export default function App() {
  return (
    <View>
      <Text>Bezier Line Chart</Text>
      <LineChart
        data={{
          labels: ['January', 'February', 'March', 'April', 'May', 'June'],
          datasets: [
            {
                data: [9, 7, 6, 4, 2, 5],
                strokeWidth: 2,
                color: (opacity = 1) => purple,
                 // optional
              },
              {
                data: [9, 4, 6, 8, 8, 2],
                strokeWidth: 2,
                color: (opacity = 1) => black,
                colors: 'purple' // optional
              },
              {
                data: [9, 4, 7, 8, 2, 4],
                strokeWidth: 3,
                color: (opacity = 1) => blue, // optional
              },
          ],
        }}
        width={Dimensions.get('window').width} // from react-native
        height={220}
        yAxisLabel="$"
        yAxisSuffix="k"
        yAxisInterval={1} // optional, defaults to 1
        chartConfig={{
          backgroundColor: 'grey',
          backgroundGradientFrom: 'grey',
          backgroundGradientTo: 'grey',
          decimalPlaces: 2, // optional, defaults to 2dp
          color: (opacity = 1) => rgba(255, 255, 255, ${opacity}),
          labelColor: (opacity = 1) => rgba(255, 255, 255, ${opacity}),
          style: {
            borderRadius: 16,
          },
          propsForDots: {
            r: '',
          },
          propsForBackgroundLines: {
            color: 'black',
            stroke: 'black',
            strokeDasharray:[],
          },
          useShadowColorFromDataset: true
        }}
        bezier
        style={{
          marginVertical: 8,
          borderRadius: 16,
        }}
      />
    </View>
  );
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ECF0F1',
    padding: 8,
  },
  paragraph: {
    margin: 24,
    fontSize: 18,
    fontWeight: 'bold',
    textAlign: 'center',
  },
});