Geolocation.js

/**
 * 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
 */
/* eslint no-console: 0 */
'use strict';


var React = require('react-native');
var {
  StyleSheet,
  Text,
  View,
} = React;

var Geolocation = React.createClass({
  watchID: (null: ?number),

  getInitialState: function() {
    return {
      initialPosition: 'unknown',
      lastPosition: 'unknown',
    };
  },

  componentDidMount: function() {
    navigator.geolocation.getCurrentPosition(
      (initialPosition) => this.setState({initialPosition}),
      (error) => console.error(error)
    );
    this.watchID = navigator.geolocation.watchPosition((lastPosition) => {
      this.setState({lastPosition});
    });
  },

  componentWillUnmount: function() {
    navigator.geolocation.clearWatch(this.watchID);
  },

  render: function() {
    return (
      <View>
        <Text>
          <Text style={styles.title}>Initial: </Text>
          {JSON.stringify(this.state.initialPosition.coords)}
        </Text>
        <Text>
          <Text style={styles.title}>Current: </Text>
          {JSON.stringify(this.state.lastPosition.coords)}
        </Text>
      </View>
    );
  }
});

var styles = StyleSheet.create({
  title: {
    fontWeight: '500',
  },
});

module.exports = Geolocation;