在 FlatList 上使用 React Native 搜索过滤器

Question

I am trying to search through a flatlist based on a search bar text. The problem I am running into is that when the user mistypes...say they wanted to type "burger" but typed "burget" by mistake then it returns nothing as it should. When the user deletes the "t" then it should re-render the flatlist again with the last text matching the "burge" part.

note: using react-native-elements search bar which allows me to call the text with just e or event.

What I have so far in the Main.js file:

searchText = (e) => {
    let text = e.toLowerCase();
    let trucks = this.state.data;

    // search by food truck name
    let filteredName = trucks.filter((truck) => {
      return truck.name.toLowerCase().match(text); 
    });

    // if no match and text is empty
    if(!text || text === '') {
      console.log('change state');
        this.setState({
          data: initial
        });
      }
    // if no name matches to text output
    else if(!Array.isArray(filteredName) && !filteredName.length) {
      console.log("not name");
      this.setState({
        data: [],
      });
    }
    // if name matches then display
    else if(Array.isArray(filteredName)) {
      console.log('Name');
      this.setState({
        data: filteredName,
      });
    }
   };

<View style={styles.container}>
  <SearchBar
    round
    lightTheme
    containerStyle={styles.search}
    ref="search"
    textInputRef="searchText"
    onChangeText={this.searchText.bind(this)}
    placeholder='Search by Truck Name...'
   />
   <TruckList getTruck={(truck) => this.setTruck(truck)} truckScreen={this.truckScreen} data={this.state.data}/>
</View>

then the TruckList.JS:

export default class TruckList extends Component {
    // rendering truck screen
    renderTruckScreen = (item) => {
        this.props.truckScreen();
        this.props.getTruck(item);
    }

    render() {
        return(
            <List style={styles.list}>
                <FlatList
                    data={this.props.data}
                    renderItem={({ item }) => (
                        <ListItem
                            roundAvatar
                            avatar={{uri: item.pic1}}
                            avatarStyle={styles.avatar}
                            title={item.name}
                            titleStyle={styles.title}
                            subtitle={
                                <View style={styles.subtitleView}>
                                    <Text style={styles.subtitleFood}>{item.food}</Text>
                                    <View style={styles.subtitleInfo}>
                                        <Icon 
                                            name="favorite"
                                            size={20}
                                            color={"#f44336"}
                                            style={styles.subtitleFavorite}
                                        />
                                        <Text style={styles.subtitleFavoriteText}>{item.favorited} favorited</Text>
                                    </View>
                                </View>
                            }
                            onPress={() => this.renderTruckScreen(item)}
                        />
                    )}
                    keyExtractor={(item) => item.uid}
                    ListFooterComponent={this.footer}
                />
            </List>
        )
      }
    }

I have tried a few other ways to no avail. Also the only solutions I have seen working for React Native are with ListView which will be depreciated in time. So I am trying to do this with the new FlatList Component.

Thanks for your help!

Answer 1

I came across this same issue today when trying to implement a filter / search function on the new FlatList component. This is how I managed to solve it:

By creating another item in the state of the parent component called noData, you can set that to true when there are no results that match your search and then render your FlatList conditionally.

My implementation is slightly different to yours, but if I had to adjust your code it would look something like this:

Searchtext function:

searchText = (e) => {
    let text = e.toLowerCase()
    let trucks = this.state.data
    let filteredName = trucks.filter((item) => {
      return item.name.toLowerCase().match(text)
    })
    if (!text || text === '') {
      this.setState({
        data: initial
      })
    } else if (!Array.isArray(filteredName) && !filteredName.length) {
      // set no data flag to true so as to render flatlist conditionally
      this.setState({
        noData: true
      })
    } else if (Array.isArray(filteredName)) {
      this.setState({
        noData: false,
        data: filteredName
      })
    }
  }

Then pass the noData bool to your TruckList component:

<TruckList getTruck={(truck) => this.setTruck(truck)} 
truckScreen={this.truckScreen} data={this.state.data} noData={this.state.noData}/>

Then render your FlatList in the TruckList component only if there are results:

<List style={styles.list}>
{this.props.noData ? <Text>NoData</Text> : <FlatList {...} />}         
</List>

That should then take care of handling user typing errors - as it will re-render the flatlist as soon as there are no results, and will remember the previous search state when you remove the typing error..

Let me know if that helps!

Answer 2

For a useful in-memory search you should keep initial data seperately.

I have more simple solution for this.

This solution for in-memory search on FlatList's data and uses it String.prototype​.includes() method to search substring.

You can find full source code of this component in this gist; https://gist.github.com/metehansenol/46d065b132dd8916159910d5e9586058

My initial state;

this.state = {
  searchText: "",
  data: [],
  filteredData: []
};

My SearchBar component (it comes from react-native-elements package);

<SearchBar
  round={true}
  lightTheme={true}
  placeholder="Search..."
  autoCapitalize='none'
  autoCorrect={false}
  onChangeText={this.search}
  value={this.state.searchText}
/>

My search method;

search = (searchText) => {
  this.setState({searchText: searchText});

  let filteredData = this.state.data.filter(function (item) {
    return item.description.includes(searchText);
  });

  this.setState({filteredData: filteredData});
};

And last my FlatList's DataSource expression;

<FlatList
  data={this.state.filteredData && this.state.filteredData.length > 0 ? this.state.filteredData : this.state.data}
  keyExtractor={(item) => `item-${item.id}`}
  renderItem={({item}) => <ListItem
    id={item.id}
    code={item.code}
    description={item.description}
  />}
/>

Happy coding...

Answer 3

Update: This blog can help you better understand the searching in a FlatList.

FYI: If you have huge online data then you can also use algolia .

I adjusted the above code for me in order to make it work properly. The reason is that when user removes the last wrong character, code search this new string from a previous search list (state) which does not contain all objects, although it had to search from a full list available. So, I have two list now. One contains full list of objects and second contains only rendered list of objects which is changing upon search.

handleSearchInput(e){
    let text = e.toLowerCase()
    let fullList = this.state.fullListData;
    let filteredList = fullList.filter((item) => { // search from a full list, and not from a previous search results list
      if(item.guest.fullname.toLowerCase().match(text))
        return item;
    })
    if (!text || text === '') {
      this.setState({
        renderedListData: fullList,
        noData:false,
      })
    } else if (!filteredList.length) {
     // set no data flag to true so as to render flatlist conditionally
       this.setState({
         noData: true
       })
    }
    else if (Array.isArray(filteredList)) {
      this.setState({
        noData: false,
        renderedListData: filteredList
      })
    }
  }

Answer 4

Here is my solution:

You need to have a backup of your data

this.state = {
    data: [],
    backup: []
}

on search method

search = txt => {
    let text = txt.toLowerCase()
    let tracks = this.state.backup
    let filterTracks = tracks.filter(item => {
    if(item.name.toLowerCase().match(text)) {
      return item
    }
  })
  this.setState({ data: filterTracks })
}

Explanation: when calling setState on your data it will changed to current state and cannot be changed again.

So backup data will handle to filter your data.

Answer 5

Make Search Bar Filter for List View Data in React Native

For Real-Time Searching in List View using Search Bar Filter

• We will load the list from the network call and then show it to the user.
• The user can search the data by entering the text in TextInput.
• After inserting the text SearchFilterFunction will be called We will compare the list data with the inserted data and will make a new Data source.
• We will update the data source attached to the ListView.
• It will re-render the list and the user will be able to see the filtered data.

 //This is an example code to Add Search Bar Filter on Listview// import React, { Component } from 'react'; //import react in our code. import { Text, StyleSheet, View, FlatList, TextInput, ActivityIndicator, Alert, } from 'react-native'; //import all the components we are going to use. export default class App extends Component { constructor(props) { super(props); //setting default state this.state = { isLoading: true, text: '' }; this.arrayholder = []; } componentDidMount() { return fetch('https://jsonplaceholder.typicode.com/posts') .then(response => response.json()) .then(responseJson => { this.setState( { isLoading: false, dataSource: responseJson }, function() { this.arrayholder = responseJson; } ); }) .catch(error => { console.error(error); }); } SearchFilterFunction(text) { //passing the inserted text in textinput const newData = this.arrayholder.filter(function(item) { //applying filter for the inserted text in search bar const itemData = item.title ? item.title.toUpperCase() : ''.toUpperCase(); const textData = text.toUpperCase(); return itemData.indexOf(textData) > -1; }); this.setState({ //setting the filtered newData on datasource //After setting the data it will automatically re-render the view dataSource: newData, text: text, }); } ListViewItemSeparator = () => { //Item sparator view return ( <View style={{ height: 0.3, width: '90%', backgroundColor: '#080808', }} /> ); }; render() { if (this.state.isLoading) { //Loading View while data is loading return ( <View style={{ flex: 1, paddingTop: 20 }}> <ActivityIndicator /> </View> ); } return ( //ListView to show with textinput used as search bar <View style={styles.viewStyle}> <TextInput style={styles.textInputStyle} onChangeText={text => this.SearchFilterFunction(text)} value={this.state.text} underlineColorAndroid="transparent" placeholder="Search Here" /> <FlatList data={this.state.dataSource} ItemSeparatorComponent={this.ListViewItemSeparator} renderItem={({ item }) => ( <Text style={styles.textStyle}>{item.title}</Text> )} enableEmptySections={true} style={{ marginTop: 10 }} keyExtractor={(item, index) => index.toString()} /> </View> ); } } const styles = StyleSheet.create({ viewStyle: { justifyContent: 'center', flex: 1, marginTop: 40, padding: 16, }, textStyle: { padding: 10, }, textInputStyle: { height: 40, borderWidth: 1, paddingLeft: 10, borderColor: '#009688', backgroundColor: '#FFFFFF', }, });

Click Hear for more idea

Answer 6

ref - https://medium.freecodecamp.org/how-to-build-a-react-native-flatlist-with-realtime-searching-ability-81ad100f6699

constructor(props) {
super(props);
this.state = {
  data: [],
  value: ""
};

this.arrayholder = [];
}

Next fetching data :-

_fetchdata = async () => {
const response = await fetch("https://randomuser.me/api?results=10");
const json = await response.json();
this.setState({ data: json.results });

this.arrayholder = json.results;
};

Next define searchFilterFunction :-

searchFilterFunction = text => {
this.setState({
  value: text
});


const newData = this.arrayholder.filter(item => {
  const itemData = item.email.toLowerCase();

  const textData = text.toLowerCase();

  return itemData.indexOf(textData) > -1;
});

this.setState({ data: newData });
};

rendering searchView:-

    <TextInput
      style={{ height: 40, borderColor: "gray", borderWidth: 1 }}
      onChangeText={text => this.searchFilterFunction(text)}
    />

Don't forget to import TextInput from "react-native";

Answer 7

You can Search your data by following these steps :

<TextInput onChangeText={(text) => searchData(text)} value={input} />

***Please Note *searchData is my function whom I passing a text prop*** 

const searchData = (text) => {
    const newData = restaurantsData.filter((item) => {
        return item.title.search(text) > -1;
    });
    setRestaurantsData(newData);
    setInput(text);
};

Note RestaurantsData is my data array

Answer 8

FYI : data is the subtext to be searched, this is a basic search implemented as the data to be searched is looked into every list item of an array which is a copy of the actual array/array of objects and finally its state is set whether match found or not between 0 to ( actualArray.length-1 ) and the temporary arrayData is rendered if there is at least one match else actualArray is rendered

 implementSearch(data) { temp = []; var count = 0; var searchData = data.toUpperCase(); var arr = this.state.personDetail; for (var i = 0; i < arr.length; i++) { var actualData = arr[i].name.toUpperCase(); if (actualData.includes(searchData)) { temp.push(arr[i]); count++; } } this.setState({ tempArray: temp, matches: count, searchValue: data }); }

Hope this helps

Answer 9

My search method; from @metehan-senol

search = (searchText) => {
 this.setState({searchText: searchText});

 let filteredData = this.state.data.filter(function (item) {
   return item.description.includes(searchText);
 });

 this.setState({filteredData: filteredData});
};

the search method of could be simplify and Eslint proof like so

search = (searchText) => {
  const searched = searchText.toLowerCase();
  this.setState(prevState => ({
    searchText: searched,
    filteredData: prevState.data.filter(item =>
      item.description.toLowerCase().includes(searched)
    ),
  }));
}; 

Answer 10

Do filter by applying

let filterData= data.filter((item) => {
  return item.name.toLowerCase().match(text)
})
if (!text || text === '') {
  this.setState({
    datasource: initial
  })
} else if (!Array.isArray(filterData) && !filterData.length) {
  // set no data flag to true so as to render flatlist conditionally
  this.setState({
    noData: true
  })
} else if (Array.isArray(filterData)) {
  this.setState({
    noData: false,`enter code here`
    dataSource: filterData
  })`enter code here`
}

Answer 11

This is not the best solution in terms of performance, but if you do not have a large amount of data, then feel free to use this function:

  searchFilter () {
    return this.props.data.filter((item) => {
       const regex = new RegExp(this.state.searchInput, "gi")
       return item.label.match(regex);
    })
  }

And then in your FlatList component:

  <FlatList
    data={this.searchFilter()}
    renderItem={this.renderItem}
    keyExtractor={(item) => item.value}
  />

Answer 12

const SearchUser = (e) =>{ console.log(e) const setProject = Project.filter(item => item.name.toLowerCase().includes(e.toLowerCase()) ) console.log(setProject) setfetch(setProject) }