I have a list of data that shows posts feed, whenever user scrolls, the list automatically scrolls multiple times up or down which results in a very bad UX
tried the workaround provided here:
https://stackoverflow.com/questions/43611485/prevent-flatlist-from-scrolling-when-new-items-are-added#=
but it doesn't seem to work for me.
<FlatList
keyboardDismissMode = 'on-drag'
keyboardShouldPersistTaps = 'always'
getItemLayout={(data, index) => (
{length: 575, offset: 575 * index, index}
)}
onScroll = {(event) => {
this.flatListOffset = event.nativeEvent.contentOffset.y
this.setState({
scrollOffset: event.nativeEvent.contentOffset.y
})
}}
contentContainerStyle={{
flexGrow: 1,
width: Dimensions.get('window').width
}}
refreshControl={
<RefreshControl
progressViewOffset={120}
refreshing={this.state.refreshing}
onRefresh={this._onRefresh.bind(this)}
/>
}
ref={(feedView) => (this.feedView = feedView)}
data={this.state.feed}
onEndReached={() => {
if (this.state.hasNextPage && !this.state.loadingMore) {
this.paginateFeed()
}
}}
ListHeaderComponent={this._renderCirclesBar}
ListEmptyComponent={this._renderEmptyState}
ListFooterComponent={() =>
!this.state.loadingMore ? null : (
<ActivityIndicator color="#2962FF" size="large" />
)
}
keyExtractor={this._keyExtractor}
renderItem={this._renderItem}
/>
then at some point:
this.setState({ feed: this.state.feed.concat(....) })
a GIF explaining the issue:
https://gifyu.com/image/9gDD
User PureComponent for rendering and set prop disableVirtualization={true} in flatlist
Related
I have implemented a delete feature for the image editor app.
Case: If the user added a number of images in edit mode and wants to delete the unnecessary layer of the image from the editor then allows to delete the selected layer from the array.
Issue: when deleted the selected layer from the array the remaining image swaps its position and size to deleted image position and size. Even if I double-check the scale value and position remain the same as I fixed. This issue occurs if am not using the loder and if am using the loder then the image did not swap their position and scale.
Where I handled the states: I am handling the states in the component and I also checked if I handled the states in redux same error occurred. App speed to slow if handled with redux.
Here is my code.
const onDeleteLayerSequence = data => {
let indexing = data.length;
data.forEach(item => {
indexing--;
item.key = indexing;
});
setInputData(data);
setIsDelete(!isDelete);
};
const deleteLayer = index => {
const filterItem = [
...inputData.slice(0, index),
...inputData.slice(index + 1, inputData.length),
];
onDeleteLayerSequence(filterItem);
};
useEffect(() => {
setImageArray(inputData.filter(item => item.type == 'image'));
// setLoader(true);
}, [isDelete]);
return (
<>
<AutoDragSortableView
dataSource={inputData}
parentWidth={util.WP(100)}
childrenWidth={util.WP(100)}
childrenHeight={util.WP(12)}
keyExtractor={(item, index) => item.id}
renderItem={(item, index) => render_item(item, index)}
onDataChange={data => onSelectLayer(data)}
onClickItem={(data, i) => replaceImage(data, i)}
/>
</View>
</DraggablePanel>
<View style={styles.editImageWrapper}>
<ViewShot
ref={reference}
options={{format: 'jpg', quality: 1.0, result: 'base64'}}>
<ImageBackground
style={[
styles.templateContainer,
{backgroundColor: background},
]}
resizeMode="stretch"
source={selectTemplate}>
{isFocused &&
imageArray &&
imageArray.map((item, i) => {
return (
<component.PinchZoomView
minScale={0.1}
maxScale={5}
scale={item.scale}
translateX={item.translateX}
translateY={item.translateY}
data={value =>
modifyValues(value, item.layer, item.key)
}
key={i}
style={[
styles.pinchImagePosition,
{
zIndex: item.key,
},
]}>
<ImageCarousel>
<Image
source={{
uri: item.editImage,
height: util.WP(100),
width: util.WP(100),
}}
key={item}
resizeMode="contain"
/>
</ImageCarousel>
</component.PinchZoomView>
);
})}
</ImageBackground>
</ViewShot>
</View>
</>
)
I'm trying to recreate Instagram's double tap on an item and a heart appears for a few seconds. Im currently rendering text items in a flatist (1 item per page) and I want the user to be able to double tap the text section and a heart will appear.
I can't seem to get both the flatList and the animation to work together. Any ideas? In my current code it will only render the flatList and not the Animated.image. I tried wrapping the animated image in an oppress in a touchable without feedback, still no luck
const onDoubleTap = useCallback(() => {
//console.log("tapped");
scale.value = withSpring(1, undefined, (isFinished) => {
if (isFinished) {
scale.value = withDelay(500, withSpring(0));
console.log("Double Tapped");
}
});
}, []);
return (
<TapGestureHandler
numberOfTaps={2}
onActivated={onDoubleTap}
>
<Animated.View>
<FlatList
horizontal={false}
decelerationRate={"fast"}
snapToAlignment={"center"}
snapToInterval={Dimensions.get("screen").height}
data={flatl}
// keyExtractor={(item, index) => `id_${index}`}
style={styles.fullScreen}
renderItem={({ item }) => (
<View style={[{ ...styles.fullHeight }]}>
<Text>{item.name}</Text>
</View>
)}
/>
<AnimatedImage
source={require("../assets/heart.png")}
style={[
styles.image,
rStyle,
]}
resizeMode={"center"}
/>
</Animated.View>
</TapGestureHandler>
);
}
I created the function name getOrientation() and put it at useEffect so that whenever I rotate the device, it will rerender the component and show me which orientation the device is.
I also created the variable to determine the orientation by using hook
getOrientation()
const [orientation, setOrientation] = useState("")
const window = useWindowDimensions()
const getOrientation = () => {
if (window.height < window.width) {
setOrientation("LANDSCAPE")
} else {
setOrientation("PORTRAIT")
}
return orientation
}
at useEffect
useEffect(() => {
getOrientation()
})
console.log(orientation)
My problem is that I want to set the numsColumns = 2 in Flatlist (LANDSCAPE) and equals to 1 for the portrait mode but the error popup telling me that I cannot change the numColumns on the fly. What should I do ?
Here is my flatlist
<View style={styles.container}>
<FlatList
contentContainerStyle={{
paddingLeft: insets.left,
paddingRight: insets.right,
}}
data={dishes.dishes}
numColumns={orientation == "LANDSCAPE" ? 2 : 1}
renderItem={({ item, index }) => (
<Tile
style={styles.tileItem}
key={index}
title={item.name}
caption={item.description}
onPress={() => navigation.navigate('Dishdetail_Screen', { dishId: item.id })} // passing infor from one to another screen
// chevron={false}
featured
imageSrc={{
uri: baseUrl + item.image
}}
/>
)}
keyExtractor={item => item.id.toString()} />
</View>
This creepy error
enter image description here
P/s: I'm the fresh React-Native developer. Thanks everyone who is checking my problems
Try adding a key prop to your Flatlist like so with the value being ur orientation:
<FlatList
key={orientation} // add key prop here
contentContainerStyle={{
paddingLeft: insets.left,
paddingRight: insets.right,
}}
data={dishes.dishes}
numColumns={orientation == "LANDSCAPE" ? 2 : 1}
renderItem={({ item, index }) => (
<Tile
style={styles.tileItem}
key={index}
title={item.name}
caption={item.description}
onPress={() => navigation.navigate('Dishdetail_Screen', { dishId: item.id })} // passing infor from one to another screen
// chevron={false}
featured
imageSrc={{
uri: baseUrl + item.image
}}
/>
)}
keyExtractor={item => item.id.toString()} />
I'm fetching data from an API and implementing search in a FlatList but the keyboard dismisses automatically after every key-press.
I'm refering this article but implementing it in a Functional Component.
const renderHeader = () => {
return <SearchBar
placeholder="Type Here..."
lightTheme
round
onChangeText={text => searchFilterFunction(text)}
value={value}
autoCorrect={false} />;
}
const searchFilterFunction = (text) => {
setValue(text);
const newData = APIData.filter(item => {
const itemData = `${item.name.toUpperCase()}`;
const textData = text.toUpperCase();
return itemData.includes(textData);
});
setData(newData);
}
return (
<FlatList
keyExtractor={(item) => item._id}
data={data}
ItemSeparatorComponent={renderSeparator}
ListHeaderComponent={renderHeader}
ListFooterComponent={renderFooter}
onRefresh={handleRefresh}
refreshing={refreshing}
renderItem={({ item }) => (
<Card>
<Card.Content style={{ flexDirection: "row" }}>
<Text>{"Name: " + item.name}</Text>
<Text>{"Status: " + (item.isaccepted ? "Accepted" : "Pending")}</Text>
<Text>{"ID: " + item.id}</Text>
</Card.Content>
</Card>
)} />
)
Thanks in advance.
I was doing same thing, adding search bar as a header to FlatList. Unfortunately, this also updates the header when you update the flatlist data when search filtering is complete and hence focusing out of SearchBar. At the end, due to time constraints, I ended up putting SearchBar at the top of FlatList.
Try rendering your ListHeaderComponent as JSX element directly, instead of using callback
<FlatList
ListHeaderComponent={
<View>
<Text>I am the header</Text>
</View>
}
...props
/>
I'm currently struggling in making my FlatList applying the changes I do to it. What I am wanting right now is that when I click an item in my flatlist, that it highlights in a certain color. I followed an approach done by a guy but I am having the problem that to me is not working the update once I click.
I can see through console that all I am doing performs a modification but I think that I am missing some point with extraData parameter since it is not re-rendering with the backgroundColor that I would like to apply.
The code I have is as following, I know that the style I am applying is correct since if i substitute in the map styles.list per styles.selected, everything gets the background I would like to be applied to the elements I click.
So summarizing, the issue I think I have is that the flatlist is not re-rendering so it doesn't show the modifications I perform on it. Any idea of what I am doing wrong? Any tip?
render() {
const { students, studentsDataSource, loading, userProfile } = this.props.navigation.state.params.store;
this.state.dataSource = studentsDataSource._dataBlob.s1.map(item => {
item.isSelect = false;
item.selectedClass = styles.list;
return item;
})
const itemNumber = this.state.dataSource.filter(item => item.isSelect).length;
return (
<View style={styles.container}>
<Item rounded style={styles.searchBar}>
<Input placeholder='Group Name'/>
</Item>
<FlatList
style={{
flex: 1,
width: "100%",
}}
data={this.state.dataSource}
ItemSeparatorComponent={this.FlatListItemSeparator}
renderItem={ ({ item }) => (
<ListItem avatar style={[styles.list, item.selectedClass]}
onPress={() => this.selectItem(item)}>
<Left>
{!item.voteCount && <Avatar unseen={true} /> }
{!!item.voteCount > 0 && <Avatar />}
</Left>
<Body>
<Text>{item.name}</Text>
<Text note>{item.group}</Text>
</Body>
</ListItem>
)
}
listKey={item => item.key}
extraData={this.state}
/>
</View>
);
}
Here we can find the state and SelectItem functions:
constructor(props) {
super(props)
this.state = {
dataSource : [],
}
}
//FlatListItemSeparator = () => <View style={styles.line} />;
selectItem = data => {
//{console.log("inside SelectItem=", data)}
data.isSelect = !data.isSelect;
data.selectedClass = data.isSelect? styles.selected: styles.list;
const index = this.state.dataSource.findIndex( item => data.key === item.key);
this.state.dataSource[index] = data;
this.setState({
dataSource: this.state.dataSource,
});
console.log("This state has the changes:=",this.state.dataSource)
};
Well the main issue was that I was not using the .setState and instead I was doing assignations which killed the listeners.