onEndReached in Flatlist issue - react-native

If I enclose the flatlist in a View then my onEndReached triggers infinitely if I remove the enclosing View onEndReached is not triggered at all.
render() {
return (
<Root>
<Container>
<Content>
<View>
{this.state.listView && (
<FlatList
data={this.state.variants}
keyExtractor={this._keyExtractor}
onEndReachedThreshold={0.5}
onEndReached={({ distanceFromEnd }) => {
console.log(
"on end reached ",
distanceFromEnd
);
this.loadMore();
}}
numColumns={1}
renderItem={({ item, index }) => (
<CatalogRow
item={item}
in_wishlist={this.state.in_wishlist}
toggleWishlist={() =>
this.toggleWishlist(item.title)
}
listView={this.state.listView}
/>
)}
/>
)}
</View>
</Content>
</Container>
</Root>
);
}
And my distanceFromEnd takes values like 0 , 960,1200 when it is trigerred. What does it indicate?
I'm using react-native 0.47.2

I have same problem with react-native 0.50.3
<Flatlist> must not be used in a <ScrollView> if you want to use onEndReached because Flatlist can not found the height.
Use a <View> instead

It was because of the enclosing <Content> tag. Sometimes embedding react-native tags with native-base tags causes such issues. I replaced the content and container tag with View tags and now it works fine.

I have same problem with RN 0.52
That look like because Flatlist can not found the heigh. So he can not find the end of list.
Fix by wrap your flatlist by a View with flex=1
<View style={{flex: 1}} > <Flatlist /> <View>

I would use it like this:
handleMore = () => {
// fetch more here
};
<FlatList
onEndReached={this.handleMore}
/>

Related

React native List footer component not rendering(funtion component)

I am trying to achieve pagination for infinite scrolling in react native. When loading, I want to render the loading spinner at the bottom of the Flat list component. (Note: I'm using Expo for this app)
const renderFooter = () => {
if (!category.loading) return null;
return (
<View style={spinnerStyles.container}>
<ActivityIndicator animating size="large" color="#0000ff" />
</View>
);
};
return (
<View style={styles.container}>
<FlatList
columnWrapperStyle={{ justifyContent: "space-between" }}
numColumns={2}
data={category.data}
renderItem={categoryItem}
keyExtractor={(item) => item._id + item.sub_category}
onEndReachedThreshold={0}
listFooterComponent={renderFooter}
onEndReached={() => loadMore()}
/>
</View>
);
The loading spinner not correctly working with the flat list footer.
Has anyone run into this issue before, or does anyone have a solution?
Sorry, it's my simple syntax error. It's actually ListFooterComponent not listFooterComponent. Now it's working fine, Thank you.
Instead of calling the refrence, call the function. It should look something like this.
ListFooterComponent={renderFooter()}

React native Flatlist TouchableOpacity OnPress Not Working On Android

Can some help me with this issue. On press not working in Flatlist render function. here my code. i checked other screens touch case working fine but when i try it in Flatlist it's not working
render(){
return (
<View style={styles.container} >
<FlatList
data={this.state.categories}
numColumns={2}
keyExtractor={item => item.id}
renderItem={item => this.renderItem(item)}
/>
</View>
);
}
renderItem = ({item,index}) => {
return (
<TouchableOpacity onPress={() => this.moveToLocation(item.id)} style={styles.items}>
<Image source={{uri:item.img}}
resizeMode="center"
style={styles.itemsimg} />
<Text style={{textAlign:'center',fontSize:20, }} onPress={() => this.moveToLocation(item.id)}>{item.name}</Text>
</TouchableOpacity>
);
}
You need to wrap your row element (inside your renderItem method) inside tag. TouchableWithoutFeedback takes onPress as it's prop where you can provide onPress event.
For TouchableWithoutFeedback refer
https://facebook.github.io/react-native/docs/touchablewithoutfeedback.html
if onPress is not workingin the flatlist's render method try using onTouchStart method of the components if they have in the flatList's render method.

React native Flatlist inside modal does not show data sometime

I am trying to to data using Flatlist inside a Modal. But sometimes (Not always) data is not displayed at all. Just empty screen. I am using expo client for test. Below is my code. This render() method is actually in a custom component. So, Modal is inside a custom component. I am not sure Modal has to cause any issue here.
// sometime flatlist does not work when inside a modal
render(){
return (
<View>
{ this.props.visible && this.renderChildModal()}
{ this.props.visible &&
<Modal
animationType="slide"
transparent={false}
visible={true}
onRequestClose={() => {
//Alert.alert('Modal has been closed.');
}}>
<View>
<View style={this.styles.buttonContainer}>
<TouchableOpacity style={this.styles.button}
onPress={this.props.onDone}>
<Text style={styles.labelButton}>Done</Text>
</TouchableOpacity>
</View>
<FlatList
data={this.state.items}
extraData ={this.state}
renderItem={({ item }) => (
<CheckBox
title={item.name}
checked={item.checked}
onPress={()=>this.onSelect(item.id-1)}
/>
)}
keyExtractor={item => item.id.toString()}
/>
</View>
</Modal>
}
</View>
)
}
It was not a problem with Modal. I was calling component named MultiSelect in screen as below,
<MultiSelect
items={specialities}
selectedItems={profile.specialities}
onItemSelected={this.onSelectedSpecialitiesChange}
visible={this.state.specialitiesModalVisible}
onDone={this.specialityMultiSelectDone}
>
</MultiSelect>
Sometime specialities is empty as it is retrieved from server asynchronously.
So, I changed my code as below,
{specialities.length>0 &&
<MultiSelect
items={specialities}
selectedItems={profile.specialities}
onItemSelected={this.onSelectedSpecialitiesChange}
visible={this.state.specialitiesModalVisible}
onDone={this.specialityMultiSelectDone}
>
</MultiSelect> }
That solves the issue.

Last item in React native flat list goes beyond screen

I have a flatlist with some styles on the outer containers as follows.
<View style={containerStyle}>
// more jsx components come here
<View style={resultContainerStyle}>
<FlatList
data={results}
keyExtractor={(item) => (item.id && item.id.toString())}
renderItem={({ item, index }) => (
<ListItem
item={item}
selectItem={selectItem}
/>
)}
/>
</View>
</View>
The issue is that the last values of the list go beyond the view of the screen and there is no way to view it unless a fixed height is put on the parent container. Is it possible to do this without a fixed height.
A SafeAreaView can be used to limit the view to the "safe" areas of the screen(avoiding the notch and curved bottom. Checkout the following example
<SafeAreaView style={containerStyle}>
// more jsx components come here
<View style={resultContainerStyle}>
<FlatList
data={results}
keyExtractor={(item) => (item.id && item.id.toString())}
renderItem={({ item, index }) => (
<ListItem
item={item}
selectItem={selectItem}
/>
)}
/>
</View>
</SafeAreaView>
more examples can be found at the react native docs.

How do I render different data types from a fetched json?

I was using...
<FlatList
data={this.state.dataSource}
renderItem={({item}) => <Text>{item.username} {item.name}</Text>}
keyExtractor={({id}, index) => id}
/>
...to render two texts in React Native but now I've got an uri in my json...
How do I render the image in an IM style (thumbnail, username and name)?
Add a renderItem method and then put everything you need in there. Once you make the renderItem method you can throw it into your FlatList.
renderItem({ item }) {
return (
<View>
<Image
source={{uri: item.uri}}
/>
<Text>
{item.username}
</Text>
<Text>
{item.name}
</Text>
</View>
);
}
Then use the method inside the FlatList (the .bind makes sure it stays in the right context)
<FlatList
data={this.state.dataSource}
renderItem={this.renderItem.bind(this)}
keyExtractor={({id}, index) => id}
/>
You can build a component that takes your fields as its props, containing multiple Texts and an Image using your uri as the source. Style this like you would any other component, and then pass that component into renderItem.
You can embed the component immediately to the renderItem like this if the flatlist item is not complicated ( has a lot of component )
<FlatList
data={this.state.dataSource}
renderItem={({item}) => {
<View>
<Image source={{uri: item.uri.image}}/>
<Text>{item.userName}</Text>
<Text>{item.name}</Text>
</View>
}}
keyExtractor={(i) => i.toString()}
/>