2.2 KiB
id | title | layout | category | permalink | next |
---|---|---|---|---|---|
basics-component-listview | ListView | docs | The Basics | docs/basics-component-listview.html | basics-dimensions |
On mobile devices, lists are a core element in many applications. The ListView
component is a special type of View
that displays a vertically scrolling list of changing, but similarly structured, data.
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.
Unlike the more generic
ScrollView
, theListView
only renders elements that are currently showing on the screen, not all the elements at once.
The ListView
component requires two properties, 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 useListView
. 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={{paddingTop: 22}}>
<ListView
dataSource={this.state.dataSource}
renderRow={(rowData) => <Text>{rowData}</Text>}
/>
</View>
);
}
}
// App registration and rendering
AppRegistry.registerComponent('AwesomeProject', () => ListViewBasics);