React Native useState not auto Updating? - react-native

Question

why useState auto update? I'll press button and not showing textinput. but I can save file without change. textinput will be showing. sorry my bad english
import React, { useState,useEffect } from 'react';
import {Text, TextInput, View, Button,} from 'react-native';
const Test = ({navigation}) => {
const [textInput, settextInput] = useState([]);
useEffect(() => {
addTextInput = (key) => {
textInput.push([<TextInput style={{backgroundColor :'#7ACB4A',marginTop:10}} key={key} />]);
settextInput(textInput);
console.log(textInput);
}
},[textInput]);
return(
<View>
<Button title='+' onPress={() =>
addTextInput(textInput.length)} />
{textInput.map((value, index) => {
return value
})}
<Text>{textInput.length}</Text>
</View>
);
}
export default Test;

Answer 1

I have a few suggests to make your code better.
Don't change state value if not in use 'setState'.
This is false by nature and causes errors.
addTextInput = (key) => {
textInput.push([<TextInput style={{backgroundColor :'#7ACB4A',marginTop:10}} key={key} />]);
settextInput(textInput);
console.log(textInput);
}
State merely contains value, it should not contain different things. You should return TextInput in your map function.
I try rewrite your code, sorry because my english. Hope help you
code:
const [textInput, setTextInput] = React.useState(['1', '2'])
const addTextInput = (key: string) => {
const tempInput = textInput.concat([key])
setTextInput(tempInput)
}
return (
<View style={{ alignItems: 'center', justifyContent: 'center', flex: 1 }}>
<Button title="+" onPress={() => addTextInput(textInput.length.toString())} />
{textInput.map((value, index) => {
return (
<TextInput style={{ backgroundColor: '#7ACB4A', marginTop: 10, width: '70%' }} key={index + ''} />
)
})}
<Text>{textInput.length}</Text>
</View>
)
}