Develop Reference

How to add button in React Native Flatlist?

I am trying to create a very simple question-and-answer app.
If I click on the show answer button then the answer should show only where I click, but now all answers are showing when I click on the button. I fetch question answers from Firestore. What is the problem Please check my Firestore data and Flatlist code. please check the images, Thank you in advance for your support
import React, { useState, useEffect } from 'react';
import { ActivityIndicator, FlatList, View, Text, Pressable, Button, StyleSheet } from 'react-native';
import {firebase} from '../config';
const Testing = ({ navigation }) =>{
const [users, setUsers] = useState([]);
const todoRef = firebase.firestore().collection('dd11');
const [showValue, setShowValue] = useState(false);
useEffect(() => {
todoRef.onSnapshot(
querySnapshot => {
const users = []
querySnapshot.forEach((doc) => {
const { QuestionOne, ans, optionOne, optionTwo, optionThree, optionFour
} = doc.data()
users.push({
id: doc.id,
QuestionOne, ans, optionOne, optionTwo, optionThree, optionFour
})
})
setUsers(users)
}
)
}, [])
return (
<View style={{ flex:1,}}>
<FlatList
data={users}
numColumns={1}
renderItem={({item}) => (
<Pressable >
<View>
<View style={{paddingLeft: 10, paddingRight: 10,}}>
{item.QuestionOne && <Text>{item.QuestionOne}</Text>}
{item.optionOne && <Text>{item.optionOne}</Text>}
{item.optionTwo && <Text>{item.optionTwo}</Text>}
{item.optionThree && <Text>{item.optionThree}</Text>}
{item.optionFour && <Text>{item.optionFour}</Text>}
{showValue? item.ans &&<Text style={{color: 'green'}} >{item.ans}</Text> : null}
<Button title="Show Answer" onPress={() => setShowValue(!showValue)} />
</View>
</View>
</Pressable>
)} />
</View>
);}
export default Testing;

you can try this, by maintaining an array of indexes, only those will be shown :)
NOte: also letmeknow if you want that func that if answer is shown and you want to hide it on press again.
import React, { useState, useEffect } from 'react';
import { ActivityIndicator, FlatList, View, Text, Pressable, Button, StyleSheet } from 'react-native';
import {firebase} from '../config';
const Testing = ({ navigation }) =>{
const [users, setUsers] = useState([]);
const todoRef = firebase.firestore().collection('dd11');
const [showValue, setShowValue] = useState(false);
const [answerIndexs,setAnsIndex] = useState([])
useEffect(() => {
todoRef.onSnapshot(
querySnapshot => {
const users = []
querySnapshot.forEach((doc) => {
const { QuestionOne, ans, optionOne, optionTwo, optionThree, optionFour
} = doc.data()
users.push({
id: doc.id,
QuestionOne, ans, optionOne, optionTwo, optionThree, optionFour
})
})
setUsers(users)
}
)
}, [])
const onPressOfShowAnswer = (index) => {
const existingIndexs = [...answerIndexs]
if(!existingIndexs.includes(index)){
existingIndexs.push(index)
}else{
existingIndexs.splice(index,1)
}
setAnsIndex(existingIndexs)
}
return (
<View style={{ flex:1,}}>
<FlatList
data={users}
numColumns={1}
renderItem={({item,index}) => (
<Pressable >
<View>
<View style={{paddingLeft: 10, paddingRight: 10,}}>
{item.Q1 && <Text>{item.QuestionOne}</Text>}
{item.optionOne && <Text>{item.optionOne}</Text>}
{item.optionTwo && <Text>{item.optionTwo}</Text>}
{item.optionThree && <Text>{item.optionThree}</Text>}
{item.optionFour && <Text>{item.optionFour}</Text>}
{ answerIndexs.includes(index) ? item.ans &&<Text style={{color: 'green'}} >{item.ans}</Text> : null}
<Button title="Show Answer" onPress={() => onPressOfShowAnswer(index)} />
</View>
</View>
</Pressable>
)} />
</View>
);}
export default Testing;

Search in SectionList React Native

I have a SectionList in the Support.js:
import React, {useState} from 'react';
import { StyleSheet, View, Text, Dimensions, StatusBar, SectionList, Pressable, Linking } from 'react-native';
import { DrawerActions } from '#react-navigation/native';
import MaterialIcon from 'react-native-vector-icons/MaterialIcons';
import Feather from 'react-native-vector-icons/Feather';
import Main from './Main'
import SearchBar from './SearchBar';
const WINDOW_HEIGHT = Dimensions.get('window').height;
const DATA = [
{
title: "Stanbul",
data: [<Text onPress={()=>{Linking.openURL('tel:Phone number');}}>Phone number</Text>]
},
{
title: "Antalya",
data: [<Text onPress={()=>{Linking.openURL('tel:Phone number');}}>Phone number</Text>]
},
{
title: "Rome",
data: [<Text onPress={()=>{Linking.openURL('tel:Phone number');}}>Phone number</Text>]
},
{
title: "Milano",
data: [<Text onPress={()=>{Linking.openURL('tel:Phone number');}}>Phone number</Text>]
}
];
const Item = ({ title }) => (
<View style={styles.item}>
<Text style={styles.title}>{title}</Text>
</View>
);
export default function Support({ navigation }) {
const [searchPhrase, setSearchPhrase] = useState("");
const [clicked, setClicked] = useState(false);
(item.toUpperCase().includes(searchPhrase.toUpperCase().trim().replace(/\s/g, ""))) {
return <Item title={item}/>;
}
};
return(
<View style={styles.mainContainer}>
<StatusBar backgroundColor={'#fdf38a'} barStyle='dark-content'/>
<View style={styles.appBar}>
<MaterialIcon name="menu" size={32} color="#2e2a00" backgroundColor={'none'} onPress={() => navigation.dispatch(DrawerActions.openDrawer())}/>
<Text style={styles.appBarText}>Support</Text>
<Feather name="x" size={32} color="#2e2a00" backgroundColor={'none'} onPress={() => navigation.navigate(Main)}/>
</View>
<View style={styles.mainContent}>
<SearchBar
searchPhrase={searchPhrase}
setSearchPhrase={setSearchPhrase}
clicked={clicked}
setClicked={setClicked}
/>
<SectionList
sections={DATA}
keyExtractor={(item, index) => item + index}
renderItem={({ item }) => <Item title={item} />}
renderSectionHeader={({ section: { title } }) => (<Text style={styles.header}>{title}</Text>)}
/>
</View>
</View>
);
}
In the SectionList I have a name of the city and the phone number.
How can I make it so that when I type in the name of the city in the search bar, only the corresponding item is displayed?
SearchBar is already written and it's a simple TextInput that takes 4 arguments:
clicked - state of clicked or not
setClicked - function to change the state of clicked
searchPhrase - currrent text in the TextInput
setSearchPhrase - function to change the searchPhrase

You can filter the array you are using in the list based on the search input
sections={
DATA.filter((city)=>city.title.toUpperCase().includes(searchPhrase.toUpperCase()))
}

Not sure how to map variable to show in app

Here's the function-
const setLoading = (value) => {
const messages = dashboards.data.message.filter((item) => {
const title = item.dashboardTitle || item.dashboardName;
return title.toLowerCase().startsWith(value.toLowerCase());
});
setFiltered(messages);
console.log(filtered);
};
I want to display the variable 'messages' separately in my app, how would I do that? 'messages' variable needs to be displayed within the default react native 'Text' component. I have written down 'messages' below within Text component but currently it's not displaying anything (since it is within function) -
import React, { useState, useEffect, useReducer } from 'react';
import { View, Text, StyleSheet, FlatList, ActivityIndicator, Keyboard} from 'react-native';
import { Searchbar } from 'react-native-paper';
import { theme } from '../theme';
import MaterialIcons from 'react-native-vector-icons/MaterialIcons';
import { TouchableOpacity } from 'react-native-gesture-handler';
import { apiStateReducer } from '../reducers/ApiStateReducer';
import CognitensorEndpoints from '../services/network/CognitensorEndpoints';
import DefaultView from '../components/default/DefaultView';
import DashboardListCard from '../components/DashboardListCard';
const AppHeader = ({
scene,
previous,
navigation,
searchIconVisible = false,
}) => {
const [dashboards, dispatchDashboards] = useReducer(apiStateReducer, {
data: [],
isLoading: true,
isError: false,
});
const [filtered, setFiltered] = useState([]);
const setLoading = (value) => {
const messages = dashboards.data.message.filter((item) => {
const title = item.dashboardTitle || item.dashboardName;
return title.toLowerCase().startsWith(value.toLowerCase());
});
setFiltered(messages);
console.log(filtered);
};
const dropShadowStyle = styles.dropShadow;
const toggleSearchVisibility = () => {
navigation.navigate('Search');
};
useEffect(() => {
CognitensorEndpoints.getDashboardList({
dispatchReducer: dispatchDashboards,
});
}, []);
return (
<>
<View style={styles.header}>
<View style={styles.headerLeftIcon}>
<TouchableOpacity onPress={navigation.pop}>
{previous ? (
<MaterialIcons
name="chevron-left"
size={24}
style={styles.visible}
/>
) : (
<MaterialIcons
name="chevron-left"
size={24}
style={styles.invisible}
/>
)}
</TouchableOpacity>
</View>
<Text style={styles.headerText}>
{messages}
</Text>
<View style={styles.headerRightIconContainer}>
{searchIconVisible ? (
<TouchableOpacity
style={[styles.headerRightIcon, dropShadowStyle]}
onPress={toggleSearchVisibility}>
<MaterialIcons name="search" size={24} style={styles.visible} />
</TouchableOpacity>
) : (
<View style={styles.invisible} />
)}
</View>
</View>
</>
);
};

If your messages variable is an array you can map it
{messages.map((message, key)=>(
<Text style={styles.headerText}>
{message.dashboardName}
</Text>
))}

Since your messages variable is stored in 'filtered' state, you can map it by doing this:
{filtered.map((item, index) => <Text key={index}>{item.dashboardName}<Text>)}

TypeError: undefined is not a function (near '...data.map...')

I updated my code thanks to your help.
When I launch the app with Expo, the opening works but I lost my scan icon which does not appear in my screen.
This icon appeared previously.
The idea is to scan some barcodes in order to display relevant data stemming from products.
Here is my new code:
import React, { useState, useEffect } from "react";
import {
StyleSheet,
Text,
View,
FlatList,
Button,
AsyncStorage,
} from "react-native";
import { useNavigation } from "#react-navigation/core";
import { TouchableOpacity } from "react-native-gesture-handler";
import { FontAwesome5 } from "#expo/vector-icons";
import { MaterialCommunityIcons } from "#expo/vector-icons";
import { ActivityIndicator } from "react-native-paper";
function ProductsScreen() {
const navigation = useNavigation();
const [data, setData] = useState([]);
const [isLoading, setisLoading] = useState(true);
useEffect(() => {
const fetchData = async () => {
const data = await AsyncStorage.getItem("userData");
setData(data);
setisLoading(false);
};
fetchData();
}, []);
console.log(data);
return isLoading ? (
<ActivityIndicator />
) : (
<>
{data ? (
<FlatList
data={dataArray}
keyExtractor={(item) => item.name}
renderItem={({ item }) => (
<>
<Text>{item.brand}</Text>
<View style={styles.scan}>
<MaterialCommunityIcons
name="barcode-scan"
size={40}
color="black"
onPress={() => {
navigation.navigate("CameraScreen");
}}
/>
</View>
</>
)}
/>
) : null}
</>
);
}
export default ProductsScreen;
I would appreciate your comments please.

You could use ? (optional chaining) to confirm data doesnt yield to undefined before mapping.
data?.map((data, index) => {return <>....</>}

You need to return from data.map function to render the array items
return isLoading ? (
<ActivityIndicator />
) : (
<>
{data?.map((data, index) => {
return <View key ={index}>
<Text> {data.products_name_fr} </Text>
<Text> {data.brands} </Text>
<Text> {data.image_url} </Text>
<View style={styles.scan}>
<MaterialCommunityIcons
name="barcode-scan"
size={40}
color="black"
onPress={() => {
navigation.navigate("CameraScreen");
}}
/>
</View>
</View>;
})}
</>
);
Or short-hand of return
return isLoading ? (
<ActivityIndicator />
) : (
<>
data?.map((data, index) => (
<View key ={index}>
<Text> {data.products_name_fr} </Text>
<Text> {data.brands} </Text>
<Text> {data.image_url} </Text>
<View style={styles.scan}>
<MaterialCommunityIcons
name="barcode-scan"
size={40}
color="black"
onPress={() => {
navigation.navigate("CameraScreen");
}}
/>
</View>
</View>;
))
</>
);

I changed my code like this but I have the same error. Besides, the part of code which begins from: const styles=Stylesheet.create seems to be not active
import React, { useState, useEffect } from "react";
import { StyleSheet, Text, View, Button, AsyncStorage } from "react-native";
import { useNavigation } from "#react-navigation/core";
import { TouchableOpacity } from "react-native-gesture-handler";
import { FontAwesome5 } from "#expo/vector-icons";
import { MaterialCommunityIcons } from "#expo/vector-icons";
import { ActivityIndicator } from "react-native-paper";
import axios from "axios";
function ProductsScreen() {
const navigation = useNavigation();
const [data, setData] = useState([]);
const [isLoading, setisLoading] = useState(true);
useEffect(() => {
const fetchData = async () => {
const data = await AsyncStorage.getItem("userData");
setisLoading(false);
setData(data);
};
fetchData();
}, []);
return isLoading ? (
<ActivityIndicator />
) : (
<>
{data?.map((data, index) => {
return (
<>
key ={index}
<Text> {data.products_name_fr} </Text>
<Text> {data.brands} </Text>
<Text> {data.image_url} </Text>
<View style={styles.scan}>
<MaterialCommunityIcons
name="barcode-scan"
size={40}
color="black"
onPress={() => {
navigation.navigate("CameraScreen");
}}
/>
</View>
</>
);
})}
</>
);
const styles = StyleSheet.create({
products: {
alignItems: "center",
justifyContent: "center",
},
scan: {
marginLeft: 30,
position: "absolute",
bottom: 0,
right: 20,
marginBottom: 60,
marginRight: 30,
padding: 10,
borderRadius: 10,
backgroundColor: "#ff9234",
},
});
}
export default ProductsScreen;

I changed a little bit my code and I got another type of error : Invariant violation: Text strings must be rendered within a component. I will really appreciate your comments and support to fix this
return isLoading ? (
<ActivityIndicator />
) : (
<>
data?.map((data, index) => (
<>
<Text> {data.products_name_fr} </Text>
<Text> {data.brands} </Text>
<Text> {data.image_url} </Text>
<View style={styles.scan}>
<MaterialCommunityIcons
name="barcode-scan"
size={40}
color="black"
onPress={() => {
navigation.navigate("CameraScreen");
}}
/>
</View>
</>
))
</>
);
}

In the useEffect, set the data as array. Example
const = [data, setData] = useState([]); // do this in your state
setData([data]); //do this in your useEffet hook

Screen switching by press on button react native

I just started to learn React-native. In this app I have a two buttons in header, first 'Todo', second 'Tags'. I want to chang content by press on these buttons. I think I need to change state.for clarityWhat I mean, when i tap on the button Tags, below I get TagScreen component, exactly the same for the button Todo. How to connect these components so that they work correctly?
app.js
import React, { useState } from 'react'
import { StyleSheet, View, FlatList } from 'react-native'
import { Navbar } from './src/Navbar'
import { TagScreen } from './src/screens/TagScreen'
import { TodoScreen } from './src/screens/TodoScreen'
export default function App() {
const [todos, setTodos] = useState([])
const [tags, setTags] = useState([])
const [appId, setAppId] = useState([])
const addTodo = title => {
setTodos(prev => [
...prev,
{
id: Date.now().toString(),
title
}
])
}
const addTags = title => {
setTags(prev => [
...prev,
{
id: Date.now().toString(),
title
}
])
}
const removeTags = id => {
setTags(prev => prev.filter(tag => tag.id !== id))
}
const removeTodo = id => {
setTodos(prev => prev.filter(todo => todo.id !== id))
}
return (
<View>
<Navbar title='Todo App!' />
<View style={styles.container}>
<TagScreen addTags={addTags} tags={tags} removeTags={removeTags}/>
{/* <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} /> */}
{/* HERE MUST CHANGED COMPONENTS */}
</View>
</View>
)
}
const styles = StyleSheet.create({
container: {
paddingHorizontal: 30,
paddingVertical: 20
}
})
navbar.js
import React from 'react'
import { View, Text, StyleSheet, Button, TouchableOpacity } from 'react-native'
export const Navbar = ({ title }) => {
return (
<View style={styles.padding}>
<View style={styles.navbar}>
<TouchableOpacity
style={styles.button}
>
<Text>Todo</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
>
<Text>Tags</Text>
</TouchableOpacity>
<Text style={styles.text}>{title}</Text>
</View>
</View>
)
}

well you need to track the visiblity of what is visible in your state,
in your App component, do this;
const [showTodos, setShowTodos] = useState(false);
const makeTodosInvisible= () => setShowTodos(false);
const makeTodosVisible = () => setShowTodos(true);
return (
<View>
<Navbar onTodoPress={makeTodosVisible } onTagPress={makeTodosInvisible} title='Todo App!' />
<View style={styles.container}>
{showTodos
? <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} />
: <TagScreen addTags={addTags} tags={tags} removeTags={removeTags}/>
}
{/* <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} /> */}
{/* HERE MUST CHANGED COMPONENTS */}
</View>
</View>
)
and in your navbar.js do this
export const Navbar = ({ title, onTodoPress, onTagPress}) => {
return (
<View style={styles.padding}>
<View style={styles.navbar}>
<TouchableOpacity
style={styles.button}
onPreesed={onTodoPress} // will hide Tags and show Todos
>
<Text>Todo</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
onPreesed={onTagPress} // will show Tags and hide Todos
>
<Text>Tags</Text>
</TouchableOpacity>
<Text style={styles.text}>{title}</Text>
</View>
</View>
)
}