Develop Reference

Getting data from a class component to Functional component - React Native

I'm pretty new to React Native and don't have the most experience with javascript so although this may be very simple I have no idea what to do. I have a class Component which acts like a popup in my app. It pops up on press of a touchable opacity and displays a little menu. I am trying to get the id of the button that is pressed on that menu and send it back to the functional component main screen (where the touchable opacity to open the menu is). I can get the id of the button but I'm struggling to get this data out of the popup and back into my main screen(functional component)
Here is my Code for the Main Screen:
import { StyleSheet, Text, View, Image,TouchableOpacity} from 'react-native'
import React,{useState} from 'react'
import tw, { create } from 'twrnc';
import Map from "../components/Map"
import { SafeAreaView } from 'react-native-safe-area-context';
import { BottomPopup } from '../components/popup';
import { selectTrucks} from '../slices/navSlice';
import { useSelector } from 'react-redux';
const Logistics = () => {
const Trucks = useSelector(selectTrucks);
let popupRef = React.createRef()
const onShowPopup = () => {
popupRef.show()
}
const onClosePopup = () => {
popupRef.close()
}
return (
<View style={{flex:1,resizeMode:'contain'}}>
<View style={tw`h-12/16`}>
<Map/>
</View>
<TouchableOpacity onPress={onShowPopup} style={{top:'-68%'}}>
<Image
source = {{uri: "https://icon-library.com/images/app-menu-icon/app-menu-icon-21.jpg" }}
style = {{width:'20%', height:40,resizeMode:'contain'}}
/>
<Text style={{color:'black',paddingLeft:2,fontSize: 26,fontWeight:"bold",top:-37,left:70}}>Truck {}</Text>
</TouchableOpacity>
<BottomPopup
title = "Select Option"
ref = {(target)=> popupRef = target}
onTouchOutside={onClosePopup}
data={Trucks.TrucksInfo}
/>
<SafeAreaView style={{top:'-13%'}}>
<Text style={{color:'darkgreen',paddingLeft:2,fontSize: 36,fontWeight:"bold"}}>123 Elmo Street</Text>
<Text style={{color:'darkgreen',paddingLeft:2,fontSize: 24,fontWeight:"bold"}}>L4L 6L8, Mississauga, Ontario</Text>
<Text style={{color:'darkgreen',paddingLeft:2,fontSize: 18,fontWeight:"bold"}}>Phone Number: 416-749-6857{'\n'}Client: Bobby Jeff{'\n'}Order Number: 7187181{'\n'}Packing Slip Number: 882929</Text>
<Text style={{color:'black',fontSize: 18,paddingLeft:2}}>Customer Notified: Yes at 2:32 PM</Text>
</SafeAreaView>
</View>
)
}
export default Logistics
const styles = StyleSheet.create({})
And Here is the code for the class component popup:
import { Modal,Dimensions,TouchableWithoutFeedback,StyleSheet,View,Text,FlatList,TouchableOpacity} from "react-native";
import React from "react";
import { useNavigation } from '#react-navigation/native';
import Logistics from "../screens/Logistics";
const deviceHeight = Dimensions.get('window').height
export class BottomPopup extends React.Component {
constructor(props){
super(props)
this.state = {
show:false
}
}
show = () => {
this.setState({show:true})
}
close = () => {
this.setState({show:false})
}
renderOutsideTouchable(onTouch) {
const view = <View style = {{flex:1,width:'100%'}}/>
if (!onTouch) return view
return (
<TouchableWithoutFeedback onPress={onTouch} style={{flex:1,width:'100%'}}>
{view}
</TouchableWithoutFeedback>
)
}
renderTitle = () => {
const {title} = this.props
return (
<View style={{alignItems:'center'}}>
<Text style={{
color:'#182E44',
fontSize:25,
fontWeight:'500',
marginTop:15,
marginBottom:30,
}}>
{title}
</Text>
</View>
)
}
renderContent = () => {
const {data} = this.props
return (
<View>
<FlatList
style = {{marginBottom:130}}
showsVerticalScrollIndicator = {false}
data={data}
renderItem={this.renderItem}
extraData={data}
keyExtractor={(item,index)=>index.toString()}
ItemSeparatorComponent={this.renderSeparator}
contentContainerStyle={{
paddingBottom:40
}}
/>
</View>
)
}
renderItem = ({item}) => {
return(
<TouchableOpacity
onPress={() => {this.close(),console.log(item.id)}}
>
<View style = {{height:50,flex:1,alignItems:'flex-start',justifyContent:'center',marginLeft:20}}>
<Text style={{fontSize:18,fontWeight:'normal',color:"#182E44"}}>{item.name}</Text>
</View>
</TouchableOpacity>
)
}
renderSeparator = () => {
return(
<View
style={{
opacity:0.1,
backgroundColor:'#182E44',
height:1
}}
/>
)
}
render() {
let {show} = this.state
const {onTouchOutside,title} = this.props
return (
<Modal
animationType={"fade"}
transparent={true}
visible={show}
onRequestClose={this.close}
>
<View style={{flex:1, backgroundColor:"#000000AA",justifyContent:'flex-end'}}>
{this.renderOutsideTouchable(onTouchOutside)}
<View style={{
backgroundColor:'#FFFFFF',
width:'100%',
paddingHorizontal:10,
maxHeight:deviceHeight*0.4}}
>
{this.renderTitle()}
{this.renderContent()}
</View>
</View>
</Modal>
)
}
}
The console log in the render item function gets me the number i need i just need to get this number out and back into my logistics screen

What you can do is like onTouchOutside you can pass getId function as props which will return id.
I don`t have much experience with class component. So I have add sample code in functional component. You can refer this
const MainComponent = ()=>{
const getIdFunc = (id)=>{
//You will get id here
}
return(<View>
{/* pass function here */}
<PopUpComponent getIdFunc={getIdFunc}/>
</View>)
}
const PopUpComponent = (props)=>{
return(<TouchableOpacity
onPress={()=>{
//call function by passing id here
props.getIdFunc(id)
}}
>
</TouchableOpacity>)
}

ScrollView in React Native

I created a simple app, that shows a few pictures with titles. It is something like a film gallery, where you can observe all enable films. But when I try to add ScrollView element it doesn't work when I try to scroll on my emulated Android device. How can I fix it? My code looks like this:
import React, { Component } from 'react'
import { View, ScrollView, StyleSheet } from 'react-native'
import { Header, ImageCard } from './src/components/uikit'
const url = 'https://s3.eu-central-1.wasabisys.com/ghashtag/RNForKids/00-Init/data.json'
export default class App extends Component {
constructor(props) {
super(props);
this.state = {
title: 'STAR GATE',
data: []
};
}
componentDidMount = async () => {
try {
const response = await fetch(url)
const data = await response.json()
this.setState({ data })
}
catch (e) {
console.log(e)
throw e
}
}
render() {
const { title, data } = this.state
const { container } = style
return (
<View>
<Header title={title} />
<ScrollView>
<View style={container}>
{
data.map(item => {
return <ImageCard data={item} key={item.id} />
})
}
</View>
</ScrollView>
</View>
)
}
}
const style = StyleSheet.create({
container: {
marginTop: 30,
flexDirection: 'row',
flexWrap: 'wrap',
flexShrink: 2,
justifyContent: 'space-around',
marginBottom: 150
}
})
I made it with a guide, so it should work. (Youtubes author hasn't this problem on his video).

The View inside ScrollView looks problematic. Try something like:
<ScrollView contentContainerStyle={container} >
{
data.map(item => {
return <ImageCard data={item} key={item.id} />
})
}
</ScrollView>

How to render data in ScrollView React Native (expo cli) from firebase realtime database?

I'm working on a ToDo app that is connected to the Firebase real-time database. Everything works fine. I can also store data in the Firebase database, but the problem is that I cannot get any data from the database. I want to render data in ScrollView so that the data can be displayed in ScrollView when I open my app.
Main.js
import React, { Component } from 'react';
import {
StyleSheet,
Text,
View,
TextInput,
ScrollView,
TouchableOpacity
} from 'react-native';
import Note from './Note';
import firebase from './firebase';
export default class Main extends React.Component {
constructor(props) {
super(props);
this.state = {
noteArray: [],
noteText: ''
}
}
render() {
let notes = () => {
firebase.database().ref(`todos`).on('value', function (snapshot) {
return <Note key={snapshot.val().key} keyval={snapshot.val().key} val={snapshot.val().note}
deleteMethod={() => this.deleteNote(key)}
/>
});
}
return (
<View style={styles.container}>
<View style={styles.header}>
<Text style={styles.headerText}>Todo</Text>
</View>
<ScrollView style={styles.scrollContainer}>
{notes}
</ScrollView>
<View style={styles.footer}>
<TextInput
style={styles.textInput}
onChangeText={(noteText) => this.setState({ noteText })}
value={this.state.noteText}
placeholder='Enter Task'
placeholderTextColor='white'
underlineColorAndroid='transparent'>
</TextInput>
</View>
<TouchableOpacity onPress={this.adTask.bind(this)} style={styles.addButton}>
<Text style={styles.addButtonText}>Add</Text>
</TouchableOpacity>
</View>
);
}
adTask() {
if (this.state.noteText) {
var date = new Date();
var database = firebase.database().ref('todos');
var key = database.push().key;
var todo = {
'date': date.getDay() +
'/' + (date.getMonth() + 1) +
'/' + date.getFullYear(),
'note': this.state.noteText,
key: key
}
database.child(key).set(todo);
this.setState({ noteArray: this.state.noteArray });
this.setState({ noteText: this.state.noteText });
this.setState({
noteText: this.state.noteText = ""
})
}
}
note.js
import React from 'react';
import { StyleSheet, Text, View, TouchableOpacity } from 'react-native';
import { AntDesign } from '#expo/vector-icons';
export default class Main extends React.Component {
render() {
return (
<View key={this.props.keyval} style={styles.note}>
<Text style={styles.noteText}>{this.props.val.note}</Text>
<Text style={styles.noteDate}>{this.props.val.date}</Text>
<TouchableOpacity onPress={this.props.deleteMethod} style={styles.noteDelete}>
<Text style={styles.noteDeleteText}><AntDesign name="delete" size={24} color="black" /></Text>
</TouchableOpacity>
</View>
);
}
}

You have delcared the noteArray state variable but you are not using it at all. Ideally you should setup a data change listener to realtime database and should update your local state when the data changes. You can setup a listener function and call it inside your Main.js file componentDidMount lifecycle method.
Inside this function, you can update your local state noteArray with the value received from the realtime database. You can then map over the noteArray to display your notes in your application with the help of a scrollview. I would personally suggest you to use the FlatList implementation of the react native in this use case, as this note array can grow over time. This will help you from the performace issues that you might face in the case of a long list and scrollview.
Main.js
import React, { Component } from 'react';
import {
StyleSheet,
Text,
View,
TextInput,
ScrollView,
TouchableOpacity,
FlatList
} from 'react-native';
import Note from './Note';
import firebase from './firebase';
export default class Main extends React.Component {
constructor(props) {
super(props);
this.state = {
noteArray: [],
noteText: ''
}
}
componentDidMount() {
this.listenForNotes()
}
listenForNotes() {
firebase.database().ref(`todos`).on('value', function (snapshot) {
const notes = [];
snapshot.forEach(child => {
notes.push({
note: child.val().name,
date: child.val().date,
key: child.key
});
});
this.setState({
noteArray: notes
});
});
}
adTask() {
if (this.state.noteText) {
var date = new Date();
var database = firebase.database().ref('todos');
var key = database.push().key;
var todo = {
'date': date.getDay() +
'/' + (date.getMonth() + 1) +
'/' + date.getFullYear(),
'note': this.state.noteText,
key: key
}
database.child(key).set(todo);
this.setState({ noteText: "" });
}
}
deleteNote(key) {
// your delete note function
}
render() {
return (
<View style={styles.container}>
<View style={styles.header}>
<Text style={styles.headerText}>Todo</Text>
</View>
<FlatList
data={noteArray}
renderItem={({ item, index }) => {
return (
<Note
key={item.key}
note={item.note}
date={item.date}
deleteMethod={() => this.deleteNote(key)}
/>
);
}}
key={(item) => `${item.key}`}
/>
<View style={styles.footer}>
<TextInput
style={styles.textInput}
onChangeText={(noteText) => this.setState({ noteText })}
value={this.state.noteText}
placeholder='Enter Task'
placeholderTextColor='white'
underlineColorAndroid='transparent'>
</TextInput>
</View>
<TouchableOpacity onPress={this.adTask.bind(this)} style={styles.addButton}>
<Text style={styles.addButtonText}>Add</Text>
</TouchableOpacity>
</View>
);
}
}
You should also make some changes in the Note.js file to display the passed props.
Note.js
import React from 'react';
import { StyleSheet, Text, View, TouchableOpacity } from 'react-native';
import { AntDesign } from '#expo/vector-icons';
export default class Note extends React.Component {
constructor(props) {
super(props);
}
render() {
const { note, date, key, deleteMethod } = this.props;
return (
<View key={key} style={styles.note}>
<Text style={styles.noteText}>{note}</Text>
<Text style={styles.noteDate}>{date}</Text>
<TouchableOpacity onPress={deleteMethod} style={styles.noteDelete}>
<Text style={styles.noteDeleteText}><AntDesign name="delete" size={24} color="black" /></Text>
</TouchableOpacity>
</View>
);
}
}

React Native - Modal with Flatlist items

I'm making a modal that will popup when the user clicks a flatlist button or items, and there the user will see the details about the item he/she clicks. Basically, I want to pass the items of flatlist to modal.
I'm actually done with the popup of the modal, now I have to show the details like menu description and menu price. I've found a post here in stackoverflow and I follow everything in there but I am having an error regarding with an " id ", and I can't figure out how to fix it.
Here is my code
Details.js
import React, {Component} from 'react';
import {Text, TouchableHighlight, View,
StyleSheet, Platform, FlatList, AppRegistry,
TouchableOpacity, RefreshControl, Dimensions, Modal, TextInput, TouchableWithoutFeedback, Keyboard
} from 'react-native';
import AddModal from '../Modal/AddModal';
var screen = Dimensions.get('window');
const DismissKeyboard = ({ children }) => (
<TouchableWithoutFeedback onPress = {() => Keyboard.dismiss()}>
{children}
</TouchableWithoutFeedback>
);
export default class Details extends Component {
static navigationOptions = {
title: ''
};
constructor()
{
super ()
this.state = {
data: [],
showModal: false,
id: null,
}
}
fetchData = async() => {
const { params } = this.props.navigation.state;
const response_Cat = await fetch('http://192.168.254.101:3307/categories/' + params.id);
const category_Cat = await response_Cat.json();
this.setState({data: category_Cat});
};
componentDidMount() {
this.fetchData();
};
_onRefresh() {
this.setState({ refreshing: true });
this.fetchData().then(() => {
this.setState({ refreshing: false })
});
};
_onPressItem(id) {
this.setState({
modalVisible: true,
id: id
});
}
_renderItem = ({item}) => {
return (
<TouchableHighlight
id = { item.menu_desc }
onPress = { this._onPressItem(item.menu_desc) }
>
<View>
<Text>{ this.state.id }</Text>
</View>
</TouchableHighlight>
)
};
render() {
const { params } = this.props.navigation.state;
return (
<View style = { styles.container }>
<AddModal
modalVisible = { this.state.modalVisible }
setModalVisible = { (vis) => { this.setModalVisible(vis) }}
id = { this.state.id }
/>
<FlatList
data = { this.state.data }
renderItem = { this._renderItem }
keyExtractor={(item, index) => index}
/*refreshControl = {
<RefreshControl
refreshing = { this.state.refreshing }
onRefresh = { this._onRefresh.bind(this) }
/>
}*/
/>
</View>
);
}
}
const styles = StyleSheet.create({
...
})
//AppRegistry.registerComponent('Details', () => Details);
AddModal.js
import React, {Component} from 'react';
import {Text, TouchableHighlight, View,
StyleSheet, Platform, FlatList, AppRegistry,
TouchableOpacity, RefreshControl, Dimensions, TextInput, Modal
} from 'react-native';
export default class AddModal extends Component {
constructor(props) {
super(props);
this.state = {
showModal: false,
id: null
};
}
componentWillReceiveProps(nextProps) {
this.setState({
showModal: nextProps.showModal,
id: nextProps.id,
})
}
render() {
return (
<Modal
animationType="slide"
transparent={ true }
visible={ this.state.modalVisible }
onRequestClose={() => { this.props.setModalVisible(false) }}>
<View>
<View>
<Text>{ this.state.id }</Text>
<TouchableHighlight
onPress = {() => { this.props.setModalVisible(false) }}
>
<Text>Hide Modal</Text>
</TouchableHighlight>
</View>
</View>
</Modal>
)
}
}

Just wanted to pointout an issue in your code (not related to 'id' error, id error already answer by digit). In the renderItem function, you are calling onPress = { this._onPressItem(item.menu_desc) }, it should be changed to
onPress = { () => this._onPressItem(item.menu_desc) }
I guess, you will call the onPressItem when user click on list item.
EDIT:
I have made a couple of changes to make your code working. Here are the changes.
In your AppModal.js, you are setting modal visibility in showModal: nextProps.showModal , but in the <Modal ...> you have set visible
= { this.state.modalVisible }. Also in Details.js you have written <AddModal modalVisible ...>.
First I changed showModal to modalVisible in Details.js and in AppModal.js.
Details.js
constructor()
{
super ()
this.state = {
data: [],
modalVisible: false,
id: null,
}
}
Then I changed _onPressItem(id) to _onPressItem = (id)
Made changes in renderItem as
<TouchableHighlight
id = { item.enName }
onPress = { () => this._onPressItem(item.enName) }
>
in render function I have set modal visibility as
<AddModal
...
setModalVisible = { (vis) => { this.setState({
modalVisible: vis
})
}}
...
/>
AppModal.js
Changed showModal to modalVisible
constructor(props) {
super(props);
this.state = {
modalVisible: props.modalVisible,
d: null
};
}
componentWillReceiveProps(nextProps) {
this.setState({
modalVisible: nextProps.modalVisible,
id: nextProps.id,
})
}
In the constructor, I have added modalVisible: props.modalVisible.
Hope this will help!

I guess item.menu_desc is an id of each item so it must be {item.menu_desc} not {id}. Change it like below
_renderItem = ({item}) => {
return (
<TouchableHighlight
id = { item.menu_desc }
onPress = { this._onPressItem(item.menu_desc) }
>
<View>
<Text>{ item.menu_desc }</Text>
</View>
</TouchableHighlight>
)
};

Displaying props in a second target box

I'm very new to react-native. I'm currently experimenting with it to figure out how I can use it in different ways. Presently, I'm trying to call props of a specifically tapped object and send them to an output box.
So when you tap 'Alan' or 'Steve' their name will appear in the red box.
I'd also like for the dark blue backkground to change to dark red once it's tapped?
I have had a good read of the docs, but I reckon I'm not getting it because it's new to me. I know that I don't seem to be able to access the props of Component which is obviously the class Obj extends
Guidance greatly appreciated.
import React, { Component } from 'react';
import { Text, View, TouchableOpacity } from 'react-native';
import style from './style';
class Obj extends Component {
render(){
return(
<TouchableOpacity
onPressIn={() => this.setState({tapped: true, tappedName: this.props.plrName})}
onPressOut={() => this.setState({tapped: false, tappedName: null})}>
<View style={[style.playerobject, style.shadow]}>
<Text style={[style.plrobjText]}>{this.props.plrName}</Text>
</View>
</TouchableOpacity>
)
}
}
export default class App extends Component {
constructor(props){
super(props);
this.state = {
tapped: false,
tappedName: null,
};
}
render() {
return (
<View style={[style.main]}>
<View style={[style.container, this.state.tapped ? {backgroundColor:'darkred'} : {backgroundColor:'darkblue'} ]}>
<Obj plrName='Alan' />
<Obj plrName='Steve' />
</View>
<View style={style.box }><Text>|{this.state.tapped ? this.state.tappedName : 'x'}|</Text></View>
</View>
);
}
}

import React, { Component } from 'react';
import { Text, View, TouchableOpacity } from 'react-native';
import style from './style';
class Obj extends Component {
onPressIn = () => {
this.props.onPressIn(this.props.plrName)
}
onPressOut = () => {
this.props.onPressOut()
}
render() {
return (
<TouchableOpacity
onPressIn={this.onPressIn}
onPressOut={this.onPressOut}>
<View style={[style.playerobject, style.shadow]}>
<Text style={[style.plrobjText]}>{this.props.plrName}</Text>
</View>
</TouchableOpacity>
)
}
}
export default class App extends Component {
constructor(props) {
super(props);
this.state = {
tapped: false,
tappedName: null,
};
}
onPressIn = (tappedName) => {
this.setState({ tapped: true, tappedName })
}
onPressOut = () => {
this.setState({ tapped: false, tappedName: null })
}
render() {
return (
<View style={[style.main]}>
<View style={[style.container, this.state.tapped ? { backgroundColor: 'darkred' } : { backgroundColor: 'darkblue' }]}>
<Obj plrName='Alan' onPressIn={this.onPressIn} onPressOut={this.onPressOut} />
<Obj plrName='Steve' onPressIn={this.onPressIn} onPressOut={this.onPressOut} />
</View>
<View style={style.box}><Text>|{this.state.tapped ? this.state.tappedName : 'x'}|</Text></View>
</View>
);
}
}