如何在react native中路由参数中指定默认值

import { createAppContainer } from 'react-navigation';
import { createStackNavigator } from 'react-navigation-stack';
import HomeScreen from './HomeScreen';
import DetailScreen from './DetailScreen';

// 路由配置
const AppNavigator = createStackNavigator(
  {
    Home: {
      screen: HomeScreen,
    },
    Detail: {
      screen: DetailScreen,
      navigationOptions: ({ navigation }) => ({
        // 设置默认参数值
        initialParams: {
          param1: 'default value',
          param2: 'default value',
        },
      }),
    },
  },
  {
    initialRouteName: 'Home',
  }
);

export default createAppContainer(AppNavigator);

import React from 'react';
import { View, Text } from 'react-native';

const DetailScreen = ({ navigation }) => {
  // 获取路由参数，如果没有传递参数则使用默认值
  const param1 = navigation.getParam('param1', 'default value');
  const param2 = navigation.getParam('param2', 'default value');

  return (
    <View>
      <Text>Param1: {param1}</Text>
      <Text>Param2: {param2}</Text>
    </View>
  );
};

export default DetailScreen;