53 lines
2.2 KiB
Markdown
53 lines
2.2 KiB
Markdown
---
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id: using-a-listview
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title: Using a ListView
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layout: docs
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category: The Basics
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permalink: docs/using-a-listview.html
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next: network
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previous: using-a-scrollview
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---
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The `ListView` component displays a vertically scrolling list of changing, but similarly structured, data.
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`ListView` works well for long lists of data, where the number of items might change over time. Unlike the more generic [`ScrollView`](/react-native/docs/using-a-scrollview.html), the `ListView` only renders elements that are currently showing on the screen, not all the elements at once.
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The `ListView` component requires two props: `dataSource` and `renderRow`. `dataSource` is the source of information for the list. `renderRow` takes one item from the source and returns a formatted component to render.
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This example creates a simple `ListView` of hardcoded data. It first initializes the `dataSource` that will be used to populate the `ListView`. Each item in the `dataSource` is then rendered as a `Text` component. Finally it renders the `ListView` and all `Text` components.
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> A `rowHasChanged` function is required to use `ListView`. Here we just say a row has changed if the row we are on is not the same as the previous row.
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```ReactNativeWebPlayer
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import React, { Component } from 'react';
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import { AppRegistry, ListView, Text, View } from 'react-native';
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class ListViewBasics extends Component {
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// Initialize the hardcoded data
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constructor(props) {
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super(props);
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const ds = new ListView.DataSource({rowHasChanged: (r1, r2) => r1 !== r2});
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this.state = {
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dataSource: ds.cloneWithRows([
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'John', 'Joel', 'James', 'Jimmy', 'Jackson', 'Jillian', 'Julie', 'Devin'
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])
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};
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}
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render() {
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return (
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<View style={{flex: 1, paddingTop: 22}}>
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<ListView
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dataSource={this.state.dataSource}
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renderRow={(rowData) => <Text>{rowData}</Text>}
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/>
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</View>
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);
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}
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}
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// App registration and rendering
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AppRegistry.registerComponent('ListViewBasics', () => ListViewBasics);
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```
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One of the most common uses for a `ListView` is displaying data that you fetch from a server. To do that, you will need to [learn about networking in React Native](/react-native/docs/network.html).
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