Clash Royale CLAN TAG#URR8PPP

React native set state is not working

I am trying to update state in react native component.
But its getting errors, Could someone help me.

I'm using react-native-cli verions: 2.0.1
react-native verions: 0.55.4

Here is my code:

import React, Component from 'react'

import
Button,
Text,
View,
from 'react-native';

export class ToggleButton extends Component

state =
isDone: false
;

onAction()
const value = !this.state.isDone;
this.setState( isDone: value );

const newValue = this.state.isDone;
console.log(newValue);


render()
return (
<View>
<Button
title="Action"
onPress=this.onAction
/>
</View>
)



export default ToggleButton;


2 Answers
2

You have three different solutions.

The problem is that you're loosing the reference to this, because the function is not executed in the original context, so this.setState is not a function, but a undefined.

this

this.setState

In this page there are examples for all of the approaches: https://reactjs.org/docs/handling-events.html

Change

onPress=this.onAction


to

onPress=this.onAction.bind(this)


Check: this

onAction() {

onAction = () => {

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