130 lines
3.3 KiB
JavaScript
130 lines
3.3 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow weak
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*/
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'use strict';
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var React = require('react');
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var createReactClass = require('create-react-class');
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var ReactNative = require('react-native');
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var {
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PanResponder,
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StyleSheet,
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View,
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} = ReactNative;
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var CIRCLE_SIZE = 80;
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var PanResponderExample = createReactClass({
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displayName: 'PanResponderExample',
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statics: {
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title: 'PanResponder Sample',
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description: 'Shows the use of PanResponder to provide basic gesture handling.',
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},
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_panResponder: {},
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_previousLeft: 0,
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_previousTop: 0,
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_circleStyles: {},
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circle: (null : ?{ setNativeProps(props: Object): void }),
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UNSAFE_componentWillMount: function() {
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this._panResponder = PanResponder.create({
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onStartShouldSetPanResponder: this._handleStartShouldSetPanResponder,
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onMoveShouldSetPanResponder: this._handleMoveShouldSetPanResponder,
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onPanResponderGrant: this._handlePanResponderGrant,
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onPanResponderMove: this._handlePanResponderMove,
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onPanResponderRelease: this._handlePanResponderEnd,
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onPanResponderTerminate: this._handlePanResponderEnd,
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});
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this._previousLeft = 20;
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this._previousTop = 84;
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this._circleStyles = {
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style: {
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left: this._previousLeft,
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top: this._previousTop,
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backgroundColor: 'green',
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}
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};
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},
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componentDidMount: function() {
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this._updateNativeStyles();
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},
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render: function() {
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return (
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<View
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style={styles.container}>
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<View
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ref={(circle) => {
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this.circle = circle;
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}}
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style={styles.circle}
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{...this._panResponder.panHandlers}
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/>
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</View>
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);
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},
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_highlight: function() {
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this._circleStyles.style.backgroundColor = 'blue';
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this._updateNativeStyles();
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},
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_unHighlight: function() {
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this._circleStyles.style.backgroundColor = 'green';
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this._updateNativeStyles();
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},
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_updateNativeStyles: function() {
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this.circle && this.circle.setNativeProps(this._circleStyles);
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},
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_handleStartShouldSetPanResponder: function(e: Object, gestureState: Object): boolean {
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// Should we become active when the user presses down on the circle?
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return true;
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},
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_handleMoveShouldSetPanResponder: function(e: Object, gestureState: Object): boolean {
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// Should we become active when the user moves a touch over the circle?
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return true;
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},
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_handlePanResponderGrant: function(e: Object, gestureState: Object) {
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this._highlight();
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},
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_handlePanResponderMove: function(e: Object, gestureState: Object) {
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this._circleStyles.style.left = this._previousLeft + gestureState.dx;
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this._circleStyles.style.top = this._previousTop + gestureState.dy;
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this._updateNativeStyles();
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},
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_handlePanResponderEnd: function(e: Object, gestureState: Object) {
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this._unHighlight();
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this._previousLeft += gestureState.dx;
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this._previousTop += gestureState.dy;
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},
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});
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var styles = StyleSheet.create({
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circle: {
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width: CIRCLE_SIZE,
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height: CIRCLE_SIZE,
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borderRadius: CIRCLE_SIZE / 2,
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position: 'absolute',
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left: 0,
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top: 0,
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},
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container: {
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flex: 1,
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paddingTop: 64,
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},
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});
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module.exports = PanResponderExample;
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