Created
May 2, 2017 19:38
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// Copy of Exponent snack example | |
// https://snack.expo.io/HJcgiI8kb | |
import React, { Component } from 'react'; | |
import { Text, View, FlatList, Dimensions, Button, StyleSheet } from 'react-native'; | |
const { width } = Dimensions.get('window'); | |
const style = { | |
justifyContent: 'center', | |
alignItems: 'center', | |
width: width, | |
height: 50, | |
flex: 1, | |
borderWidth: 1, | |
}; | |
const COLORS = ['deepskyblue','fuchsia', 'lightblue ']; | |
function getData(number) { | |
let data = []; | |
for(var i=0; i<number; ++i) | |
{ | |
data.push("" + i); | |
} | |
return data; | |
} | |
class ScrollToExample extends Component { | |
getItemLayout = (data, index) => ( | |
{ length: 50, offset: 50 * index, index } | |
) | |
getColor(index) { | |
const mod = index%3; | |
return COLORS[mod]; | |
} | |
scrollToIndex = () => { | |
let randomIndex = Math.floor(Math.random(Date.now()) * this.props.data.length); | |
this.flatListRef.scrollToIndex({animated: true, index: randomIndex}); | |
} | |
scrollToItem = () => { | |
let randomIndex = Math.floor(Math.random(Date.now()) * this.props.data.length); | |
this.flatListRef.scrollToIndex({animated: true, index: "" + randomIndex}); | |
} | |
render() { | |
return ( | |
<View style={styles.container}> | |
<View style={styles.header}> | |
<Button | |
onPress={this.scrollToIndex} | |
title="Tap to scrollToIndex" | |
color="darkblue" | |
/> | |
<Button | |
onPress={this.scrollToItem} | |
title="Tap to scrollToItem" | |
color="purple" | |
/> | |
</View> | |
<FlatList | |
style={{ flex: 1 }} | |
ref={(ref) => { this.flatListRef = ref; }} | |
keyExtractor={item => item} | |
getItemLayout={this.getItemLayout} | |
initialScrollIndex={50} | |
initialNumToRender={2} | |
renderItem={({ item, index}) => ( | |
<View style={{...style, backgroundColor: this.getColor(index)}}> | |
<Text>{item}</Text> | |
</View> | |
)} | |
{...this.props} | |
/> | |
</View> | |
); | |
} | |
} | |
const styles = StyleSheet.create({ | |
container: { | |
flex: 1 | |
}, | |
header: { | |
paddingTop: 20, | |
backgroundColor: 'darkturquoise', | |
alignItems: 'center', | |
justifyContent: 'center' | |
} | |
}); | |
export default class app extends Component { | |
render() { | |
return <ScrollToExample | |
data={getData(100)} | |
/> | |
} | |
} |
The scrollToItem method uses a scrollToIndex call. Is this correct?
Correct, there´s no ScrollToItem method, so, no difference at all, both uses ScrollToIndex :-/
There is a difference between ScrollToItem [We are passing item here] & ScrollToIndex[We are passing index here]. It is mentioned in the official documentation for flatlist.
There is a difference between ScrollToItem [We are passing item here] & ScrollToIndex[We are passing index here]. It is mentioned in the official documentation for flatlist.
He is telling about the above example. In the above example, both are using scrollToIndex
This is not illustrate how to use scrollToItem !!!
how to use scrollToItem in FlatList component, not Button
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The
scrollToItem
method uses ascrollToIndex
call. Is this correct?