问题
I am using react native and expo. I have some JSON data on the screen (iOS) simulator that was fetched from API. At the top, I have a search bar where users can search the data that is displayed on the screen.
For example, if the data is
A
a company
B
bcompany
A is a company symbol and a company
is a symbol name. So when user types A it should display A
company and if user type Z
it should display Z
company.
My code:
import React, { useState, useEffect } from "react";
import {
StyleSheet,
View,
TouchableWithoutFeedback,
Keyboard,
FlatList,
TextInput,
Button,
Text,
} from "react-native";
import { useStocksContext } from "../contexts/StocksContext";
import { scaleSize } from "../constants/Layout";
import { Ionicons } from "@expo/vector-icons";
import { ListItem } from "react-native";
export default function SearchScreen({ navigation }) {
const { ServerURL, addToWatchlist } = useStocksContext();
const [state, setState] = useState({
/* initial state here */
myListData: [],
search: "",
});
useEffect(() => {
renderWithData();
// FixMe: fetch symbol names from the servner and save in local SearchScreen state
}, []);
updateSearch = (event) => {
setState({ search: event.target.value });
};
renderWithData = () => {
return fetch("http://131.181.190.87:3001/all")
.then((res) => res.json())
.then((json) => {
setState({
isLoaded: true,
myListData: json,
});
setTimeout(() => {
console.log(state.myListData);
}, 10000);
});
};
let filteredItems = state.myListData.filter((item) => {
return (
item.symbol.toUpperCase().indexOf(state.search.toUpperCase()) !== -1 ||
item.name.indexOf(state.search) !== -1
);
});
let movies = state.myListData.filteredItems.map((val) => {
return (
<View key={val.symbol} style={styles.text}>
<Text style={styles.text}>{val.symbol}</Text>
<Text style={styles.text}>{val.name}</Text>
</View>
);
});
return (
<TouchableWithoutFeedback onPress={Keyboard.dismiss}>
<View style={styles.container}>
<TextInput
style={styles.textinput}
placeholder="Search here"
placeholderTextColor="white"
value={state.search}
onChange={updateSearch.bind()}
/>
<Text>csdn</Text>
<View style={styles.text}>{movies}</View>
</View>
</TouchableWithoutFeedback>
);
}
const styles = StyleSheet.create({
textinput: {
color: "white",
height: "20",
fontSize: 18,
},
text: {
color: "white",
backgroundColor: "black",
},
flatstuff: {
color: "white",
},
// use scaleSize(x) to adjust sizes for small/large screens
});
I am not sure what am I doing wrong, but if I type something on textinput, it doesn't display anything (more like the search thing is not working) and my data is still displayed on the screen except I can't search it using the textinput. Could someone please help me?
Edit: json data
Object {
"name": "Chesapeake Energy",
"symbol": "CHK",
}, Object {
"name": "C. H. Robinson Worldwide",
"symbol": "CHRW",
},
回答1:
You should use the textinput like below in React-Native
<TextInput
style={styles.textinput}
placeholder="Search here"
placeholderTextColor="white"
value={state.search}
onChangeText={text=>updateSearch(text)}
/>
You should use the onChangeText and the updateSearch should change like below
updateSearch = (text) => {
setState({ search: text });
};
Update
This is how your full component should look like, you can try it out
function SearchScreen({ navigation }) {
const { ServerURL, addToWatchlist } = useStocksContext();
const [state, setState] = useState({
/* initial state here */
myListData: [],
});
const [search, setSearch] = useState('');
useEffect(() => {
renderWithData();
// FixMe: fetch symbol names from the servner and save in local SearchScreen state
}, []);
const updateSearch = (text) => {
setSearch(text);
};
renderWithData = () => {
return fetch('http://131.181.190.87:3001/all')
.then((res) => res.json())
.then((json) => {
setState({
isLoaded: true,
myListData: json,
});
setTimeout(() => {
console.log(state.myListData);
}, 10000);
});
};
let filteredItems = state.myListData.filter((item) => {
return (
item.symbol.toUpperCase().indexOf(search.toUpperCase()) !== -1 ||
item.name.indexOf(search) !== -1
);
});
let movies = filteredItems.map((val) => {
return (
<View key={val.symbol} style={styles.text}>
<Text style={styles.text}>{val.symbol}</Text>
<Text style={styles.text}>{val.name}</Text>
</View>
);
});
return (
<TouchableWithoutFeedback onPress={Keyboard.dismiss}>
<View style={styles.container}>
<TextInput
style={styles.textinput}
placeholder="Search here"
placeholderTextColor="white"
value={search}
onChangeText={(text) => updateSearch(text)}
/>
<Text>csdn</Text>
<View style={styles.text}>{movies}</View>
</View>
</TouchableWithoutFeedback>
);
}
来源:https://stackoverflow.com/questions/62231853/how-to-display-items-on-screen-using-search-textinput-expo-react-native