react-native/Examples/UIExplorer/js/PanResponderExample.js

143 lines
4.0 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 weak
*/
'use strict';
var React = require('react');
var ReactNative = require('react-native');
var {
PanResponder,
StyleSheet,
View,
processColor,
} = ReactNative;
var CIRCLE_SIZE = 80;
var PanResponderExample = React.createClass({
statics: {
title: 'PanResponder Sample',
description: 'Shows the use of PanResponder to provide basic gesture handling.',
},
_panResponder: {},
_previousLeft: 0,
_previousTop: 0,
_circleStyles: {},
circle: (null : ?{ setNativeProps(props: Object): void }),
componentWillMount: function() {
this._panResponder = PanResponder.create({
onStartShouldSetPanResponder: this._handleStartShouldSetPanResponder,
onMoveShouldSetPanResponder: this._handleMoveShouldSetPanResponder,
onPanResponderGrant: this._handlePanResponderGrant,
onPanResponderMove: this._handlePanResponderMove,
onPanResponderRelease: this._handlePanResponderEnd,
onPanResponderTerminate: this._handlePanResponderEnd,
});
this._previousLeft = 20;
this._previousTop = 84;
this._circleStyles = {
style: {
left: this._previousLeft,
top: this._previousTop,
backgroundColor: 'green',
}
};
},
componentDidMount: function() {
this._updateNativeStyles();
},
render: function() {
return (
<View
style={styles.container}>
<View
ref={(circle) => {
this.circle = circle;
}}
style={styles.circle}
{...this._panResponder.panHandlers}
/>
</View>
);
},
_highlight: function() {
this._circleStyles.style.backgroundColor = 'blue';
this._updateNativeStyles();
},
_unHighlight: function() {
this._circleStyles.style.backgroundColor = 'green';
this._updateNativeStyles();
},
_updateNativeStyles: function() {
this.circle && this.circle.setNativeProps(this._circleStyles);
},
_handleStartShouldSetPanResponder: function(e: Object, gestureState: Object): boolean {
// Should we become active when the user presses down on the circle?
return true;
},
_handleMoveShouldSetPanResponder: function(e: Object, gestureState: Object): boolean {
// Should we become active when the user moves a touch over the circle?
return true;
},
_handlePanResponderGrant: function(e: Object, gestureState: Object) {
this._highlight();
},
_handlePanResponderMove: function(e: Object, gestureState: Object) {
this._circleStyles.style.left = this._previousLeft + gestureState.dx;
this._circleStyles.style.top = this._previousTop + gestureState.dy;
this._updateNativeStyles();
},
_handlePanResponderEnd: function(e: Object, gestureState: Object) {
this._unHighlight();
this._previousLeft += gestureState.dx;
this._previousTop += gestureState.dy;
},
});
var styles = StyleSheet.create({
circle: {
width: CIRCLE_SIZE,
height: CIRCLE_SIZE,
borderRadius: CIRCLE_SIZE / 2,
position: 'absolute',
left: 0,
top: 0,
},
container: {
flex: 1,
paddingTop: 64,
},
});
module.exports = PanResponderExample;