react-native/docs/UsingAListView.md
ronhe 79e1eacc18 Update UsingAListView.md - Add flex:1 to View
Summary:
Add flex:1 to View's style prop, so the ListView can be scrolled.
Closes https://github.com/facebook/react-native/pull/10304

Differential Revision: D3993754

Pulled By: JoelMarcey

fbshipit-source-id: 23d73b23310a5b39dea4cf3c6f3af0bf2901480f
2016-10-09 11:13:27 -07:00

2.2 KiB

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using-a-listview Using a ListView docs The Basics docs/using-a-listview.html network using-a-scrollview

The ListView component displays a vertically scrolling list of changing, but similarly structured, data.

ListView works well for long lists of data, where the number of items might change over time. Unlike the more generic ScrollView, the ListView only renders elements that are currently showing on the screen, not all the elements at once.

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.

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.

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.

import React, { Component } from 'react';
import { AppRegistry, ListView, Text, View } from 'react-native';

class ListViewBasics extends Component {
  // Initialize the hardcoded data
  constructor(props) {
    super(props);
    const ds = new ListView.DataSource({rowHasChanged: (r1, r2) => r1 !== r2});
    this.state = {
      dataSource: ds.cloneWithRows([
        'John', 'Joel', 'James', 'Jimmy', 'Jackson', 'Jillian', 'Julie', 'Devin'
      ])
    };
  }
  render() {
    return (
      <View style={{flex: 1, paddingTop: 22}}>
        <ListView
          dataSource={this.state.dataSource}
          renderRow={(rowData) => <Text>{rowData}</Text>}
        />
      </View>
    );
  }
}

// App registration and rendering
AppRegistry.registerComponent('ListViewBasics', () => ListViewBasics);

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.