Data listing process with Firebase(Firestore) in React Native.
In the video I watched, he wrote and ran the code that lists the coins belonging to the user using firestore. It did not work even though I wrote the same codes. What is the reason? the code does not give an error, the screen appears, but it does not list.
The problem is that when I did the listing in console it worked. However, when I try to list with FlatList, the screen appears blank.
import { View, Text, SafeAreaView, TouchableOpacity, FlatList } from 'react-native'
import React, { useContext, useState, useEffect } from 'react'
import IconFA5 from 'react-native-vector-icons/FontAwesome5'
import IconFA from 'react-native-vector-icons/FontAwesome'
import { deviceWidth, deviceHeight } from '../../utils/dimensions'
import { AuthContext } from '../../navigation/AuthProvider'
import { Formik, validateYupSchema } from 'formik'
import * as yup from 'yup'
import { firebase } from '@react-native-firebase/auth'
import auth from '@react-native-firebase/auth'
import firestore from '@react-native-firebase/firestore'
const color = '#aaa';
const HomeScreen = ({ navigation }) => {
const renderItem = (item) => {
<TouchableOpacity
key={item.id}
style={{
flexDirection: 'row',
width: '95%',
height: 60,
borderWidth: 1,
margin: 10,
borderRadius: 20,
padding: 10,
justifyContent: 'space-between',
alignItems: 'center'
}}>
<View style={{ flex: 1 }}>
<Text style={{
textAlign: 'left',
fontSize: 18
}}>{item.coinID}</Text>
</View>
<View style={{ flex: 1 }}>
<Text style={{
textAlign: 'right',
fontSize: 18
}}>{item.value}</Text>
</View>
</TouchableOpacity>
}
const { signOut, user } = useContext(AuthContext);
const [currentUser, setCurrentUser] = useState({});
const [userCoinList, setUserCoinList] = useState([]);
const usersColl = firestore().collection('users');
const coinsColl = firestore().collection('coins');
const userCoinsColl = firestore().collection('userCoins');
useEffect(() => {
return usersColl
.doc(user.uid)
.get()
.then(result => {
setCurrentUser(result.data());
userCoinsColl.onSnapshot((querySnapshot) => {
let list = [];
querySnapshot.forEach(doc => {
const { userID, coinID, value } = doc.data();
if (userID == user.uid) {
list.push({
id: doc.id,
userID,
coinID,
value
});
setUserCoinList(list);
}
});
});
});
}, []);
return (
<SafeAreaView style={{ width: '100%', height: '100%' }}>
<View style={{
width: '100%',
height: '90%',
padding: 5,
flex: 1,
alignItems: 'center'
}}>
<View>
<FlatList
style={{ flex: 3, backgroundColor: '#f00' }}
data={userCoinList}
keyExtractor={item => item.id}
renderItem={renderItem}
/>
{console.log(userCoinList)}
</View>
</View>
</SafeAreaView>
)
}
export default HomeScreen
Your renderItem
function does not return anything. Here is a fix.
const renderItem = (item) => {
return <TouchableOpacity
key={item.id}
style={{
flexDirection: 'row',
width: '95%',
height: 60,
borderWidth: 1,
margin: 10,
borderRadius: 20,
padding: 10,
justifyContent: 'space-between',
alignItems: 'center'
}}>
<View style={{ flex: 1 }}>
<Text style={{
textAlign: 'left',
fontSize: 18
}}>{item.coinID}</Text>
</View>
<View style={{ flex: 1 }}>
<Text style={{
textAlign: 'right',
fontSize: 18
}}>{item.value}</Text>
</View>
</TouchableOpacity>
}
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