Warm tip: This article is reproduced from stackoverflow.com, please click
react-native react-navigation react-navigation-stack

Unable to set header title dynamically in react native

发布于 2020-03-29 21:01:45

I am trying to change the Header title of new component screen dynamically but getting the following error:

TypeError: TypeError: undefined is not an object (evaluating 'navigationData.navigation.getParam')
* screens\CategoryMealsScreen.js:26:42 in navigationOptions
* screens\CategoryMealsScreen.js:10:40 in CategoryMealsScreen
- node_modules\react-native\Libraries\Renderer\oss\ReactNativeRenderer-dev.js:9473:27 in renderWithHooks
- node_modules\react-native\Libraries\Renderer\oss\ReactNativeRenderer-dev.js:11994:6 in mountIndeterminateComponent

My Code:

import React from "react";
import { Text, View, StyleSheet, Button } from "react-native";
import { CATEGORIES } from "../data/dummydata";
import Colors from "../constans/Colors";
let titleHeader = "";
const CategoryMealsScreen = props => {
  const categoryId = props.navigation.getParam("categoryId");

  const selectedCategory = CATEGORIES.find(cat => cat.id === categoryId);
  CategoryMealsScreen.navigationOptions(selectedCategory.title);
  // console.log(Object.keys(props.navigation));
  titleHeader = selectedCategory.title;
  return (
    <View style={styles.screen}>
      <Text>{selectedCategory.title}</Text>

      <Button
        title="Meals Details"
        onPress={() => props.navigation.navigate("MealsDetail")}
      />
    </View>
  );
};

CategoryMealsScreen.navigationOptions = navigationData => {
  const catId = navigationData.navigation.getParam("categoryId");
  const selectedCategory = CATEGORIES.find(cat => cat.id === catId);
  // console.log(catId);
  // console.log(navigationData.navigation.getParam("categoryId"));
  return {
    headerTitle: selectedCategory.title,
    headerStyle: {
      backgroundColor: Colors.primaryColor
    },
    headerTintColor: "white"
  };
};

const styles = StyleSheet.create({
  screen: {
    flex: 1,
    justifyContent: "center",
    alignContent: "center"
  }
});

export default CategoryMealsScreen;

I tried to console log catId and it does show the output in the console but the error remains.

I am able to get data with getParam inside the component but not in CategoryMealsScreen.navigationOptions

Some sited its problem with bable configuration but it is not working or I am doing something wrong. Right not I am using global variable titleHeader to change header title and it works but it's still a hack.

GitHub

Questioner
Ketan Ramteke
Viewed
35
Prakash Karena 2020-01-31 19:55

Problem occurs because of async task like find CATEGORIES.find(cat.. This will take a time to complete

Solution : use async/await with your fuction which wait for your task completion.

We can set title dynamically using navigationOptions directly in stack configuration.  

CategoryMeals : {
    screen : CategoryMealsScreen,
    navigationOptions: ({ navigation }) => ({
          title : navigation.getParam('categoryId', 'CategoryMeals')
    }),
},