react-native/Examples/UIExplorer/js/ScrollViewExample.js
Martin Konicek 9dee696ed8 Add scrollToEnd to ScrollView and ListView
Summary:
**Motivation**

A basic task of making a React Native ScrollView or ListView scroll to the bottom is currently very hard to accomplish:
- https://github.com/facebook/react-native/issues/8003
- https://github.com/facebook/react-native/issues/913
- http://stackoverflow.com/questions/29829375/how-to-scroll-to-bottom-in-react-native-listview

**NOTE:** If you're building something like a chat app where you want a ListView to keep scrolling to the bottom at all times, it's easiest to use the [react-native-invertible-scrollview](https://github.com/exponent/react-native-invertible-scroll-view) component rather calling `scrollToEnd` manually when layout changes. The invertible-scrollview uses a clever trick to invert the direction of the ScrollView.

This pull request adds a `scrollToEnd` method which scrolls to the bottom if the ScrollView is vertical, to the right if the ScrollView is horizontal.

The implementation is based on this SO answer:
http://stackoverflow.com/questions/952412/uiscrollview-scrol
Closes https://github.com/facebook/react-native/pull/12088

Differential Revision: D4474974

Pulled By: mkonicek

fbshipit-source-id: 6ecf8b3435f47dd3a31e2fd5be6859062711c233
2017-01-27 10:13:29 -08:00

153 lines
5.4 KiB
JavaScript

/**
* Copyright (c) 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* The examples provided by Facebook are for non-commercial testing and
* evaluation purposes only.
*
* Facebook reserves all rights not expressly granted.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL
* FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* @flow
*/
'use strict';
var React = require('react');
var ReactNative = require('react-native');
var {
ScrollView,
StyleSheet,
Text,
TouchableOpacity,
View,
Image
} = ReactNative;
exports.displayName = (undefined: ?string);
exports.title = '<ScrollView>';
exports.description = 'Component that enables scrolling through child components';
exports.examples = [
{
title: '<ScrollView>',
description: 'To make content scrollable, wrap it within a <ScrollView> component',
render: function() {
var _scrollView: ScrollView;
return (
<View>
<ScrollView
ref={(scrollView) => { _scrollView = scrollView; }}
automaticallyAdjustContentInsets={false}
onScroll={() => { console.log('onScroll!'); }}
scrollEventThrottle={200}
style={styles.scrollView}>
{THUMBS.map(createThumbRow)}
</ScrollView>
<TouchableOpacity
style={styles.button}
onPress={() => { _scrollView.scrollTo({y: 0}); }}>
<Text>Scroll to top</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
onPress={() => { _scrollView.scrollToEnd({animated: true}); }}>
<Text>Scroll to bottom</Text>
</TouchableOpacity>
</View>
);
}
}, {
title: '<ScrollView> (horizontal = true)',
description: 'You can display <ScrollView>\'s child components horizontally rather than vertically',
render: function() {
var _scrollView: ScrollView;
return (
<View>
<ScrollView
ref={(scrollView) => { _scrollView = scrollView; }}
automaticallyAdjustContentInsets={false}
horizontal={true}
style={[styles.scrollView, styles.horizontalScrollView]}>
{THUMBS.map(createThumbRow)}
</ScrollView>
<TouchableOpacity
style={styles.button}
onPress={() => { _scrollView.scrollTo({x: 0}); }}>
<Text>Scroll to start</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
onPress={() => { _scrollView.scrollToEnd({animated: true}); }}>
<Text>Scroll to end</Text>
</TouchableOpacity>
</View>
);
}
}];
class Thumb extends React.Component {
shouldComponentUpdate(nextProps, nextState) {
return false;
}
render() {
return (
<View style={styles.button}>
<Image style={styles.img} source={{uri:this.props.uri}} />
</View>
);
}
}
var THUMBS = ['https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-ash3/t39.1997/p128x128/851549_767334479959628_274486868_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851561_767334496626293_1958532586_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-ash3/t39.1997/p128x128/851579_767334503292959_179092627_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851589_767334513292958_1747022277_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851563_767334559959620_1193692107_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851593_767334566626286_1953955109_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851591_767334523292957_797560749_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851567_767334529959623_843148472_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851548_767334489959627_794462220_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851575_767334539959622_441598241_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-ash3/t39.1997/p128x128/851573_767334549959621_534583464_n.png', 'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851583_767334573292952_1519550680_n.png'];
THUMBS = THUMBS.concat(THUMBS); // double length of THUMBS
var createThumbRow = (uri, i) => <Thumb key={i} uri={uri} />;
var styles = StyleSheet.create({
scrollView: {
backgroundColor: '#6A85B1',
height: 300,
},
horizontalScrollView: {
height: 120,
},
containerPage: {
height: 50,
width: 50,
backgroundColor: '#527FE4',
padding: 5,
},
text: {
fontSize: 20,
color: '#888888',
left: 80,
top: 20,
height: 40,
},
button: {
margin: 7,
padding: 5,
alignItems: 'center',
backgroundColor: '#eaeaea',
borderRadius: 3,
},
buttonContents: {
flexDirection: 'row',
width: 64,
height: 64,
},
img: {
width: 64,
height: 64,
}
});