react-native/RNTester/js/NetInfoExample.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 * @providesModule NetInfoExample
 */
'use strict';

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

class ConnectionInfoSubscription extends React.Component<{}, $FlowFixMeState> {
  state = {
    connectionInfoHistory: [],
  };

  componentDidMount() {
    NetInfo.addEventListener(
        'change',
        this._handleConnectionInfoChange
    );
  }

  componentWillUnmount() {
    NetInfo.removeEventListener(
        'change',
        this._handleConnectionInfoChange
    );
  }

  _handleConnectionInfoChange = (connectionInfo) => {
    const connectionInfoHistory = this.state.connectionInfoHistory.slice();
    connectionInfoHistory.push(connectionInfo);
    this.setState({
      connectionInfoHistory,
    });
  };

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

class ConnectionInfoCurrent extends React.Component<{}, $FlowFixMeState> {
  state = {
    connectionInfo: null,
  };

  componentDidMount() {
    NetInfo.addEventListener(
        'change',
        this._handleConnectionInfoChange
    );
    NetInfo.fetch().done(
        (connectionInfo) => { this.setState({connectionInfo}); }
    );
  }

  componentWillUnmount() {
    NetInfo.removeEventListener(
        'change',
        this._handleConnectionInfoChange
    );
  }

  _handleConnectionInfoChange = (connectionInfo) => {
    this.setState({
      connectionInfo,
    });
  };

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

class IsConnected extends React.Component<{}, $FlowFixMeState> {
  state = {
    isConnected: null,
  };

  componentDidMount() {
    NetInfo.isConnected.addEventListener(
        'change',
        this._handleConnectivityChange
    );
    NetInfo.isConnected.fetch().done(
        (isConnected) => { this.setState({isConnected}); }
    );
  }

  componentWillUnmount() {
    NetInfo.isConnected.removeEventListener(
        'change',
        this._handleConnectivityChange
    );
  }

  _handleConnectivityChange = (isConnected) => {
    this.setState({
      isConnected,
    });
  };

  render() {
    return (
        <View>
          <Text>{this.state.isConnected ? 'Online' : 'Offline'}</Text>
        </View>
    );
  }
}

class IsConnectionExpensive extends React.Component<{}, $FlowFixMeState> {
  state = {
    isConnectionExpensive: (null : ?boolean),
  };

  _checkIfExpensive = () => {
    NetInfo.isConnectionExpensive().then(
        isConnectionExpensive => { this.setState({isConnectionExpensive}); }
    );
  };

  render() {
    return (
        <View>
          <TouchableWithoutFeedback onPress={this._checkIfExpensive}>
            <View>
              <Text>Click to see if connection is expensive:
                {this.state.isConnectionExpensive === true ? 'Expensive' :
                this.state.isConnectionExpensive === false ? 'Not expensive'
                : 'Unknown'}
              </Text>
            </View>
          </TouchableWithoutFeedback>
        </View>
    );
  }
}

exports.title = 'NetInfo';
exports.description = 'Monitor network status';
exports.examples = [
  {
    title: 'NetInfo.isConnected',
    description: 'Asynchronously load and observe connectivity',
    render(): React.Element<any> { return <IsConnected />; }
  },
  {
    title: 'NetInfo.update',
    description: 'Asynchronously load and observe connectionInfo',
    render(): React.Element<any> { return <ConnectionInfoCurrent />; }
  },
  {
    title: 'NetInfo.updateHistory',
    description: 'Observed updates to connectionInfo',
    render(): React.Element<any> { return <ConnectionInfoSubscription />; }
  },
  {
    platform: 'android',
    title: 'NetInfo.isConnectionExpensive (Android)',
    description: 'Asynchronously check isConnectionExpensive',
    render(): React.Element<any> { return <IsConnectionExpensive />; }
  },
];