Access section data from section items in react native SectionList - react-native

I need to access the information regarding the section (index, value) inside the renderItem in react-native SectionList. According to http://docs.w3cub.com/react_native/sectionlist/#renderitem section details can be passed via renderItem function. But in below code except the item all other values will be set to undefined. Is there any other possible way of doing it?
render(){
return(
<SectionList
sections={this.props.itemList}
renderItem={(item,section) => this._renderNewItem(item,section)}
renderSectionHeader={this._renderSectionHeader}
keyExtractor={(item) => item.id}
/>
)
}
_renderNewItem(item,section){
console.log(item, " ", section)
}
Sample data structure

renderItem prop passes a single parameter to the function. This parameter is an object includes item and section data.
renderItem: (info: { item: Item, index: number, section: SectionT,
separators: { highlight: () => void, unhighlight: () => void,
updateProps: (select: 'leading' | 'trailing', newProps: Object) =>
void, }, }) => ?React.Element
To get the section data you can use it like below
renderItem={({ item, section }) => this._renderNewItem(item,section)}
Update
Adding a sample example to demonstrate how it works. See it on snack.expo.io
import React, { Component } from 'react';
import { Text, View, StyleSheet, SectionList } from 'react-native';
import { Constants } from 'expo';
const data = [{key: 'New', data: [{name: 'Foo1'}, {name: 'Foo2'}]}, {key: 'Old', data: [{name:'Foo3'}, {name: 'Foo4'}]}];
export default class App extends Component {
_renderItem = ({item, section}) => (<Text>{`${item.name}(${section.key})`}</Text>)
_renderSectionHeader = ({section}) => {
return (
<View style={styles.sectionHeader}>
<Text style={styles.header}>{section.key}</Text>
</View>
)
}
render() {
return (
<View style={styles.container}>
<SectionList
sections={data}
renderItem={this._renderItem}
renderSectionHeader={this._renderSectionHeader}
/>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
paddingTop: Constants.statusBarHeight,
backgroundColor: '#ecf0f1',
},
sectionHeader: {
height: 50,
flex: 1,
backgroundColor: '#fff',
justifyContent: 'center',
paddingLeft: 10
},
header: {
fontSize: 20,
}
});

Output of this will look like attached image Link
https://i.stack.imgur.com/Y7CLF.png Output of this solution image.
https://pastebin.com/embed_js/7kYrk8kf Dummy JSON File URL Link for this Demo.
I used above mentioned JSON with Section List in following way with the help of #bennygenel code.
renderItem = ({ item, section }) => <Text>{`${item.title}`}</Text>;
renderSectionHeader = ({ section }) => {
return (
/* <View style={styles.sectionHeader}>
<Text style={styles.header}>{section.key}</Text>
</View> */
****Custom Header Component ****
<CellHeader title={section.title} />
);
};
renderSectionList = () => {
return (
<View>
<SectionList
sections={data1.results}
renderItem={this.renderItem}
renderSectionHeader={this.renderSectionHeader}
/>
</View>
);
};

Related

Sticky header on SectionList ReactNative

I need to create a screen Catalog(Categories and Products).
I'm using SectionList from React Native in order to achive this.
I need to make that Categories component stick on the top when you scroll product lists.
Is there any library that could help me with this Catalog screen ?
Please look at the image here..
import React from "react";
import { View, StyleSheet, SectionList } from "react-native";
import Text from "../Text";
const DATA = [
{
title: "Main dishes",
data: ["Pizza", "Burger", "Risotto"],
},
{
title: "Sides",
data: ["French Fries", "Onion Rings", "Fried Shrimps"],
},
{
title: "Drinks",
data: ["Water", "Coke", "Beer"],
},
{
title: "Desserts",
data: ["Cheese Cake", "Ice Cream"],
},
];
const TabCategories = () => (
<View>
<Text>Horizontal list of categories</Text>
</View>
);
const Item = ({ title }) => (
<View style={styles.item}>
<Text style={styles.title}>{title}</Text>
</View>
);
const TestSectionList = (props) => {
return (
<View style={styles.container}>
<Text style={styles.SRC}>Some React Component</Text>
<SectionList
sections={DATA}
keyExtractor={(item, index) => item + index}
renderItem={({ item }) => <Item title={item} />}
renderSectionHeader={({ section: { title } }) => (
<Text style={styles.header}>{title}</Text>
)}
StickyHeaderComponent={TabCategories}
/>
</View>
);
};
const styles = StyleSheet.create({
container: {},
SRC: {
fontWeight: "bold",
borderWidth: 1,
borderColor: "#fff",
padding: 10,
},
item: {
padding: 30,
},
header: {
fontWeight: "bold",
fontSize: 20,
},
});
export default TestSectionList;
stickySectionHeadersEnabled
Makes section headers stick to the top of the screen until the next one pushes it up
ListHeaderComponent
Rendered at the very beginning of the list
renderSectionHeader
Rendered at the top of each SECTION
I think this should do:
<SectionList
sections={DATA}
keyExtractor={(item, index) => item + index}
renderItem={({ item }) => <Item title={item} />}
ListHeaderComponent={({ section: { title } }) => (
<Text style={styles.header}>{title}</Text>
)}
renderSectionHeader={TabCategories}
stickySectionHeadersEnabled
/>
You can try this library react-native-tabs-section-list
https://github.com/bogoslavskiy/react-native-tabs-section-list
If you are talking about react-native-section-list, it inherits ScrollView props, you can check in the docs, in props section, so it has stickyHeaderComponent prop which should be exactly what you want.

Rendering items not showing up

im writing a todolist with reactnative using hooks , however when rendering todo items , its not showing up, any advice to fix this
thank you so much for your help!!!
import React, { useState } from 'react';
import { StyleSheet, FlatList, Text, View } from 'react-native';
export default function App() {
const [todos, setTodos] = useState([
{ text: 'budddy', key: '1' },
{ text: 'helloddd', key: '2' },
{ text: "hellddo", key: '3' }
])
return (
<View style={styles.container} >
<View style={styles.content}>
<FlatList data={todos} renderItem={({ item }) => {
<Text> {item.text}</Text>
}} />
</View>
</View>
);
}
const styles = StyleSheet.create({
container: {
paddingTop: 30,
},
content: {
padding: 40
},
})
Check the renderItem code you need to add return or use the implicit return of arrow function
<FlatList data={todos} renderItem={({ item }) => (
<Text> {item.text}</Text>
)} />
Use the extraData property on your FlatList component.
As per documentation:
Bypassing extraData={this.state} to FlatList we make sure FlatList will re-render itself when the state.selected changes. Without setting this prop, FlatList would not know it needs to re-render any items because it is also a PureComponent and the prop comparison will not show any changes.
here is the example code (documentation)
import React from 'react';
import {
SafeAreaView,
TouchableOpacity,
FlatList,
StyleSheet,
Text,
} from 'react-native';
import Constants from 'expo-constants';
const DATA = [
{
id: 'bd7acbea-c1b1-46c2-aed5-3ad53abb28ba',
title: 'First Item',
},
{
id: '3ac68afc-c605-48d3-a4f8-fbd91aa97f63',
title: 'Second Item',
},
{
id: '58694a0f-3da1-471f-bd96-145571e29d72',
title: 'Third Item',
},
];
function Item({ id, title, selected, onSelect }) {
return (
<TouchableOpacity
onPress={() => onSelect(id)}
style={[
styles.item,
{ backgroundColor: selected ? '#6e3b6e' : '#f9c2ff' },
]}
>
<Text style={styles.title}>{title}</Text>
</TouchableOpacity>
);
}
export default function App() {
const [selected, setSelected] = React.useState(new Map());
const onSelect = React.useCallback(
id => {
const newSelected = new Map(selected);
newSelected.set(id, !selected.get(id));
setSelected(newSelected);
},
[selected],
);
return (
<SafeAreaView style={styles.container}>
<FlatList
data={DATA}
renderItem={({ item }) => (
<Item
id={item.id}
title={item.title}
selected={!!selected.get(item.id)}
onSelect={onSelect}
/>
)}
keyExtractor={item => item.id}
extraData={selected}
/>
</SafeAreaView>
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
marginTop: Constants.statusBarHeight,
},
item: {
backgroundColor: '#f9c2ff',
padding: 20,
marginVertical: 8,
marginHorizontal: 16,
},
title: {
fontSize: 32,
},
});

Flat list single item with two buttons

A flat list displays information from an API, I want to add a delete button for each item. Where user can click on it and be able to delete this specific item.
Please check my code below.
<FlatList
numColumns={1}
data={this.state.allDocs}
renderItem={({ item }) => (
<TouchableOpacity onPress={() => Linking.openURL('http://URL')}>
<Text>{item.docName}</Text>
</TouchableOpacity>
<TouchableOpacity onPress={deleteFunction}>
<Text>Delete</Text>
</TouchableOpacity>
)}
keyExtractor={item => item.docName}
/>
import React, { Component } from "react";
import {
SafeAreaView,
View,
FlatList,
StyleSheet,
Text,
TouchableOpacity
} from "react-native";
export default class Example extends Component {
state = {
data: [
{
id: "bd7acbea-c1b1-46c2-aed5-3ad53abb28ba",
title: "First Item"
},
{
id: "3ac68afc-c605-48d3-a4f8-fbd91aa97f63",
title: "Second Item"
},
{
id: "58694a0f-3da1-471f-bd96-145571e29d72",
title: "Third Item"
}
]
};
renderItem = ({ item }) => {
return (
<View style={styles.item}>
<Text>{item.title}</Text>
<TouchableOpacity onPress={() => this.removeValue(item.id)}>
<Text>Delete</Text>
</TouchableOpacity>
</View>
);
};
removeValue = id => {
let newData = this.state.data.filter(item => item.id !== id);
this.setState({
data: newData
});
};
render() {
return (
<SafeAreaView style={styles.container}>
<FlatList
data={this.state.data}
renderItem={this.renderItem}
keyExtractor={item => item.id}
/>
</SafeAreaView>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
marginTop: 50
},
item: {
backgroundColor: "#f9c2ff",
padding: 20,
marginVertical: 8,
marginHorizontal: 16,
flexDirection: "row",
justifyContent: "space-between"
}
});
Change this according to your requirements.
Hope this will helps you. Feel free for doubts.
You just need to pass a function that will remove the document from your state like this:
export default class FlatListExample extends Component {
_openDoc = async (index) => {
const { allDocs } = this.state;
Linking.openURL(allDocs[i].url);
}
_deleteDoc = (index) => {
const { allDocs } = this.state;
allDocs.splice(index, 1);
this.setState({ allDocs });
}
render() {
const { allDocs } = this.state;
return (
<FlatList
data={allDocs}
keyExtractor={item => item.docName}
renderItem={({ item, index }) => (
<Fragment>
<TouchableOpacity onPress={() => this._openDoc(index)}>
<Text>{item.docName}</Text>
</TouchableOpacity>
<TouchableOpacity onPress={() => this._deleteDoc(index)}>
<Text>Delete</Text>
</TouchableOpacity>
</Fragment>
)} />
);
}
}

React Native FlatList won't render

I'm trying to implement a FlatList in my React Native application, but no matter what I try the darn thing just won't render!
It's intended to be a horizontal list of images that a user can swipe through, but at this point I'd be happy to just get a list of text going.
Here's the relevant code. I can confirm that every render function is called.
render() {
const cameraScreenContent = this.state.hasAllPermissions;
const view = this.state.showGallery ? this.renderGallery() : this.renderCamera();
return (<View style={styles.container}>{view}</View>);
}
renderGallery() { //onPress={() => this.setState({showGallery: !this.state.showGallery})}
return (
<GalleryView style={styles.overlaycontainer} onPress={this.toggleView.bind(this)}>
</GalleryView>
);
}
render() {
console.log("LOG: GalleryView render function called");
console.log("FlatList data: " + this.state.testData.toString());
return(
<FlatList
data={this.state.testData}
keyExtractor={this._keyExtractor}
style={styles.container}
renderItem={
({item, index}) => {
this._renderImageView(item, index);
}
}
/>
);
}
}
_keyExtractor = (item, index) => index;
_renderImageView = (item, index) => {
console.log("LOG: renderItem: " + item);
return(
<Text style={{borderColor: "red", fontSize: 30, justifyContent: 'center', borderWidth: 5, flex: 1}}>{item}</Text>
);
}
//testData: ["item1", "item2", "item3", "item4", "item5", "item6", "item7", "item8", "item9"]
I'm fairly confident this isn't some flex issue, but in case I missed something here's the relevant stylesheets too:
const styles = StyleSheet.create({
container: {
flex: 1
},
overlaycontainer: {
flex: 1,
flexDirection: 'row',
justifyContent: 'space-between'
},
});
So, what I'm expecting to happen is to see a list of text items.
What's happening instead is I see a white screen with nothing on it.
Why is this list not rendering?
You can try replicating this if you want, define FlatList inside your return().
<View>
<FlatList
data={Items}
renderItem={this.renderItems}
enableEmptySections
keyExtractor={item => item.id}
ItemSeparatorComponent={this.renderSeparator}
/>
</View>
Then declare your Items inside constant(array of objects) outside your class like this,
const Items = [
{
id: FIRST,
title: 'item1',
},
{
id: SECOND,
title: 'item2',
},
{
id: THIRD,
title: 'item3',
},
// and so on......
];
After this get your items outside render by calling a function
onSelection = (item) => {
console.log(item.title)
}
renderItems = ({ item }) => {
return(
<TouchableOpacity
onPress={() => this.onSelection(item)}>
<View>
<Text>
{item.title}
</Text>
</View>
</TouchableOpacity>
)
}
Are you not missing the return on your renderItem?
render() {
console.log("LOG: GalleryView render function called");
console.log("FlatList data: " + this.state.testData.toString());
return(
<FlatList
data={this.state.testData}
keyExtractor={this._keyExtractor}
style={styles.container}
renderItem={
({item, index}) => {
return this._renderImageView(item, index);
}
}
/>
);
}
}

Highlight a selected item in React-Native FlatList

I put together a simple React-native application to gets data from a remote service, loads it in a FlatList. When a user taps on an item, it should be highlighted and selection should be retained. I am sure such a trivial operation should not be difficult. I am not sure what I am missing.
import React, { Component } from 'react';
import {
StyleSheet,
Text,
View,
FlatList,
ActivityIndicator,
Image,
TouchableOpacity,
} from 'react-native';
export default class BasicFlatList extends Component {
constructor(props) {
super(props);
this.state = {
loading: false,
data: [],
page: 1,
seed: 1,
error: null,
refreshing: false,
selectedItem:'null',
};
}
componentDidMount() {
this.makeRemoteRequest();
}
makeRemoteRequest = () => {
const {page, seed} = this.state;
const url = `https://randomuser.me/api/?seed=${seed}&page=${page}&results=20`;
this.setState({loading: true});
fetch(url)
.then(res => res.json())
.then(res => {
this.setState({
data: page === 1 ? res.results : [...this.state.data, ...res.results],
error: res.error || null,
loading: false,
refreshing: false
});
})
.catch(error => {
this.setState({error, loading: false});
});
};
onPressAction = (rowItem) => {
console.log('ListItem was selected');
console.dir(rowItem);
this.setState({
selectedItem: rowItem.id.value
});
}
renderRow = (item) => {
const isSelectedUser = this.state.selectedItem === item.id.value;
console.log(`Rendered item - ${item.id.value} for ${isSelectedUser}`);
const viewStyle = isSelectedUser ? styles.selectedButton : styles.normalButton;
return(
<TouchableOpacity style={viewStyle} onPress={() => this.onPressAction(item)} underlayColor='#dddddd'>
<View style={styles.listItemContainer}>
<View>
<Image source={{ uri: item.picture.large}} style={styles.photo} />
</View>
<View style={{flexDirection: 'column'}}>
<View style={{flexDirection: 'row', alignItems: 'flex-start',}}>
{isSelectedUser ?
<Text style={styles.selectedText}>{item.name.first} {item.name.last}</Text>
: <Text style={styles.text}>{item.name.first} {item.name.last}</Text>
}
</View>
<View style={{flexDirection: 'row', alignItems: 'flex-start',}}>
<Text style={styles.text}>{item.email}</Text>
</View>
</View>
</View>
</TouchableOpacity>
);
}
render() {
return(
<FlatList style={styles.container}
data={this.state.data}
renderItem={({ item }) => (
this.renderRow(item)
)}
/>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
marginTop: 50,
},
selectedButton: {
backgroundColor: 'lightgray',
},
normalButton: {
backgroundColor: 'white',
},
listItemContainer: {
flex: 1,
padding: 12,
flexDirection: 'row',
alignItems: 'flex-start',
},
text: {
marginLeft: 12,
fontSize: 16,
},
selectedText: {
marginLeft: 12,
fontSize: 20,
},
photo: {
height: 40,
width: 40,
borderRadius: 20,
},
});
When user taps on an item in the list, "onPress" method is invoked with the information on selected item. But the next step of highlight item in Flatlist does not happen. 'UnderlayColor' is of no help either.
Any help/advice will be much appreciated.
You can do something like:
For the renderItem, use something like a TouchableOpacity with an onPress event passing the index or id of the renderedItem;
Function to add the selected item to a state:
handleSelection = (id) => {
var selectedId = this.state.selectedId
if(selectedId === id)
this.setState({selectedItem: null})
else
this.setState({selectedItem: id})
}
handleSelectionMultiple = (id) => {
var selectedIds = [...this.state.selectedIds] // clone state
if(selectedIds.includes(id))
selectedIds = selectedIds.filter(_id => _id !== id)
else
selectedIds.push(id)
this.setState({selectedIds})
}
FlatList:
<FlatList
data={data}
extraData={
this.state.selectedId // for single item
this.state.selectedIds // for multiple items
}
renderItem={(item) =>
<TouchableOpacity
// for single item
onPress={() => this.handleSelection(item.id)}
style={item.id === this.state.selectedId ? styles.selected : null}
// for multiple items
onPress={() => this.handleSelectionMultiple(item.id)}
style={this.state.selectedIds.includes(item.id) ? styles.selected : null}
>
<Text>{item.name}</Text>
</TouchableOpacity>
}
/>
Make a style for the selected item and that's it!
In place of this.state.selectedItem and setting with/checking for a rowItem.id.value, I would recommend using a Map object with key:value pairs as shown in the RN FlatList docs example: https://facebook.github.io/react-native/docs/flatlist.html. Take a look at the js Map docs as well: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map.
The extraData prop recommended by #j.I-V will ensure re-rendering occurs when this.state.selected changes on selection.
Your onPressAction will obviously change a bit from example below depending on if you want to limit the number of selections at any given time or not allow user to toggle selection, etc.
Additionally, though not necessary by any means, I like to use another class or pure component for the renderItem component; ends up looking something like the following:
export default class BasicFlatList extends Component {
state = {
otherStateStuff: ...,
selected: (new Map(): Map<string, boolean>) //iterable object with string:boolean key:value pairs
}
onPressAction = (key: string) => {
this.setState((state) => {
//create new Map object, maintaining state immutability
const selected = new Map(state.selected);
//remove key if selected, add key if not selected
this.state.selected.has(key) ? selected.delete(key) : selected.set(key, !selected.get(key));
return {selected};
});
}
renderRow = (item) => {
return (
<RowItem
{...otherProps}
item={item}
onPressItem={this.onPressAction}
selected={!!this.state.selected.get(item.key)} />
);
}
render() {
return(
<FlatList style={styles.container}
data={this.state.data}
renderItem={({ item }) => (
this.renderRow(item)
)}
extraData={this.state}
/>
);
}
}
class RowItem extends Component {
render(){
//render styles and components conditionally using this.props.selected ? _ : _
return (
<TouchableOpacity onPress={this.props.onPressItem}>
...
</TouchableOpacity>
)
}
}
You should pass an extraData prop to your FlatList so that it will rerender your items based on your selection
Here :
<FlatList style={styles.container}
data={this.state.data}
extraData={this.state.selectedItem}
renderItem={({ item }) => (
this.renderRow(item)
)}
/>
Source : https://facebook.github.io/react-native/docs/flatlist
Make sure that everything your renderItem function depends on is passed as a prop (e.g. extraData) that is not === after updates, otherwise your UI may not update on changes
First
constructor() {
super();
this.state = {
selectedIds:[]
};
}
Second
handleSelectionMultiple = async (id) => {
var selectedIds = [...this.state.selectedIds] // clone state
if(selectedIds.includes(id))
selectedIds = selectedIds.filter(_id => _id !== id)
else
selectedIds.push(id)
await this.setState({selectedIds})
}
Third
<CheckBox
checked={this.state.selectedIds.includes(item.expense_detail_id) ? true : false}
onPress={()=>this.handleSelectionMultiple(item.expense_detail_id)}
/>
Finally i got the solution to my problem from the answer given by Maicon Gilton