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Summary: Add basic information about the generic `ScrollView` -- talk a bit about how it renders elements and a quick compare against something like a `ListView`. Provide a simple example. Fixes #8261 Closes https://github.com/facebook/react-native/pull/8266 Differential Revision: D3465105 Pulled By: JoelMarcey fbshipit-source-id: 3a2e1eac6e877669763fc6b8bb0fc78ebe870ab1
49 lines
2.1 KiB
Markdown
49 lines
2.1 KiB
Markdown
---
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id: basics-component-listview
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title: ListView
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layout: docs
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category: Basics
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permalink: docs/basics-component-listview.html
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next: basics-integration-with-existing-apps
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---
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On mobile devices, lists are a core element in many applications. The [`ListView`](/react-native/docs/listview.html#content) component is a special type of [`View`](/react-native/docs/basics-component-view.html) that displays a *vertically* scrolling list of changing, but similarly structured, data.
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`ListView` works best for possibly lengthy datasources (e.g., from an endpoint or database), where the number of items may not be known a priori.
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> Unlike the more generic [`ScrollView`](/react-native/docs/basics-component-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 properties, `dataSource` and `renderRow`. `dataSource` is the actual source of information that will be part of the list. `renderRow` takes the data and returns a renderable component to display.
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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`. Then it renders that `ListView` with that data.
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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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```JavaScript
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import React from 'react';
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import { AppRegistry, Text, View, ListView} from 'react-native';
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var SimpleList = React.createClass({
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// Initialize the hardcoded data
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getInitialState: function() {
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var ds = new ListView.DataSource({rowHasChanged: (r1, r2) => r1 !== r2});
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return {
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dataSource: ds.cloneWithRows(['John', 'Joel', 'James', 'Jimmy', 'Jackson', 'Jillian', 'Julie'])
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};
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},
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render: function() {
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return (
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<View>
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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('MyApp', () => SimpleList);
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```
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