Passing input state from parent to child component

问题

I want to pass the value and setValue to Right component . I've done something but it's not working.I am typing but it's deleting immediately.I can't see even what I am typing to textinput.What is the proper way to do this ?

export const Vault = ({ navigation }: VaultStackNavigationProps<"Vault">) => {
  const [value, setValue] = useState("");

  React.useLayoutEffect(() => {
    navigation.setOptions({
      headerRight: () => (
        <Right
          setText={setValue}
          value={value}
        />
      ),
    });
  }, [navigation]);
  return (
   //component style
  );
};

const Right = ({ value, setText }) => {
  const [focus, setFocus] = useState(false);
  const { width } = useWindowDimensions();
  const onSearch = () => {
    setFocus(true);
  };
  const onClose = () => {
    setFocus(false);
  };

  return (
    <>
      <Animated.Viewstyle={{flexDirection: "row",justifyContent: "center",alignItems: "center",width:width - 40,
        }}
      >
       {focus && (
          <TextInput
            value={value}
            onChangeText={(text) => setText(text)}
            placeholder="Type here"
          />
        )}
        {value.length > 0 && (
          <TouchableOpacity style={{ width: width / 9 }} onPress={onClear}>
            <AntDesign name="close" size={24} color="white" />
          </TouchableOpacity>
        )}
      </Animated.View>
      {!focus && (
        <TouchableOpacity onPress={onSearch} style={{ width: width / 9 }}>
          <AntDesign name="search1" size={24} color="#64646E" />
        </TouchableOpacity>
      )}
    </>
  );
};

回答1:

Your example code cannot be run without adding more onto it. For future reference, see how to make a minimum, reproducible example.

Anyways, here is an example of passing in the state value and setter method to a child component, which I have tested:

TestComponent.js:

import React, {useState} from "react";
import {TextInput, View, Text, SafeAreaView, StyleSheet} from "react-native";

const TestComponent = props => {
    const [value, setValue] = useState("");

    return (
        <SafeAreaView style={styles.safeAreaView}>
            <View style={styles.parent}>
                <ChildComponent value={value} setValue={setValue}/>
            </View>
        </SafeAreaView>

    );
};

const ChildComponent = props => {

    const textChangeHandler = (text) => {
        props.setValue(text);
    };

    return (
        <View style={styles.child}>
            <Text>Input Some Text:</Text>
            <TextInput
                style={styles.input}
                value={props.value}
                onChangeText={textChangeHandler}
            />
        </View>
    );
};

const styles = StyleSheet.create({
    safeAreaView: {
        flex: 1,
    },
    parent: {
        flex: 1,
        justifyContent: "center",
        alignItems: "center",
    },
    child: {
        flexDirection: "row",
        marginHorizontal: 25,
        justifyContent: "center",
        alignItems: "center",
    },
    input:{
        flex: 1,
        marginHorizontal: 10,
        borderWidth: 1,
        borderColor: "black",
    }
});

export default TestComponent;

And here is the App.js file:

import React from 'react';
import {StyleSheet, SafeAreaView} from 'react-native';

import TestComponent from "./TestComponent";

export default function App() {

    return (
        <SafeAreaView style={styles.safeAreaView}>
            <TestComponent />
        </SafeAreaView>
    );
}

const styles = StyleSheet.create({
    safeAreaView: {
        flex: 1,
    }
});

来源：https://stackoverflow.com/questions/64964992/passing-input-state-from-parent-to-child-component