react-native/RNTester/js/OrientationChangeExample.js

/**
 * Copyright (c) 2015-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.
 *
 * @providesModule OrientationChangeExample
 * @flow
 */
'use strict';

const React = require('react');
const ReactNative = require('react-native');
const {
  DeviceEventEmitter,
  Text,
  View,
} = ReactNative;

import type EmitterSubscription from 'EmitterSubscription';

class OrientationChangeExample extends React.Component {
  _orientationSubscription: EmitterSubscription;

  state = {
    currentOrientation: '',
    orientationDegrees: 0,
    isLandscape: false,
  };

  componentDidMount() {
    this._orientationSubscription = DeviceEventEmitter.addListener(
      'namedOrientationDidChange', this._onOrientationChange,
    );
  }

  componentWillUnmount() {
    this._orientationSubscription.remove();
  }

  _onOrientationChange = (orientation: Object) => {
    this.setState({
      currentOrientation: orientation.name,
      orientationDegrees: orientation.rotationDegrees,
      isLandscape: orientation.isLandscape,
    });
  }

  render() {
    return (
      <View>
        <Text>{JSON.stringify(this.state)}</Text>
      </View>
    );
  }
}

exports.title = 'OrientationChangeExample';
exports.description = 'listening to orientation changes';
exports.examples = [
  {
    title: 'OrientationChangeExample',
    description: 'listening to device orientation changes',
    render() { return <OrientationChangeExample />; },
  },
];