SensorScreen.tsx

import React from 'react';
import { ScrollView, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
import * as Sensors from 'expo-sensors';
import { Subscription } from '@unimodules/core';

const FAST_INTERVAL = 16;
const SLOW_INTERVAL = 1000;

export default class SensorScreen extends React.Component {
  static navigationOptions = {
    title: 'Sensors',
  };

  render() {
    return (
      <ScrollView style={styles.container}>
        <GyroscopeSensor />
        <AccelerometerSensor />
        <MagnetometerSensor />
        <MagnetometerUncalibratedSensor />
        <BarometerSensor />
        <DeviceMotionSensor />
      </ScrollView>
    );
  }
}

interface State<M extends object> {
  data: M;
  isAvailable?: boolean;
}

abstract class SensorBlock<M extends object> extends React.Component<{}, State<M>> {
  readonly state: State<M> = { data: {} as M };

  _subscription?: Subscription;

  componentDidMount() {
    this.checkAvailability();
  }

  checkAvailability = async () => {
    const isAvailable = await this.getSensor().isAvailableAsync();
    this.setState({ isAvailable });
  };

  componentWillUnmount() {
    this._unsubscribe();
  }

  abstract getName: () => string;
  abstract getSensor: () => Sensors.DeviceSensor<M>;
  abstract renderData: () => JSX.Element;

  _toggle = () => {
    if (this._subscription) {
      this._unsubscribe();
    } else {
      this._subscribe();
    }
  };

  _slow = () => {
    this.getSensor().setUpdateInterval(SLOW_INTERVAL);
  };

  _fast = () => {
    this.getSensor().setUpdateInterval(FAST_INTERVAL);
  };

  _subscribe = () => {
    this._subscription = this.getSensor().addListener((data: any) => {
      this.setState({ data });
    });
  };

  _unsubscribe = () => {
    this._subscription && this._subscription.remove();
    this._subscription = undefined;
  };

  render() {
    if (this.state.isAvailable !== true) {
      return null;
    }
    return (
      <View style={styles.sensor}>
        <Text>{this.getName()}:</Text>
        {this.renderData()}
        <View style={styles.buttonContainer}>
          <TouchableOpacity onPress={this._toggle} style={styles.button}>
            <Text>Toggle</Text>
          </TouchableOpacity>
          <TouchableOpacity onPress={this._slow} style={[styles.button, styles.middleButton]}>
            <Text>Slow</Text>
          </TouchableOpacity>
          <TouchableOpacity onPress={this._fast} style={styles.button}>
            <Text>Fast</Text>
          </TouchableOpacity>
        </View>
      </View>
    );
  }
}

abstract class ThreeAxisSensorBlock extends SensorBlock<Sensors.ThreeAxisMeasurement> {
  renderData = () => (
    <Text>
      x: {round(this.state.data.x)} y: {round(this.state.data.y)} z: {round(this.state.data.z)}
    </Text>
  );
}

class GyroscopeSensor extends ThreeAxisSensorBlock {
  getName = () => 'Gyroscope';
  getSensor = () => Sensors.Gyroscope;
}

class AccelerometerSensor extends ThreeAxisSensorBlock {
  getName = () => 'Accelerometer';
  getSensor = () => Sensors.Accelerometer;
}

class MagnetometerSensor extends ThreeAxisSensorBlock {
  getName = () => 'Magnetometer';
  getSensor = () => Sensors.Magnetometer;
}

class MagnetometerUncalibratedSensor extends ThreeAxisSensorBlock {
  getName = () => 'Magnetometer (Uncalibrated)';
  getSensor = () => Sensors.MagnetometerUncalibrated;
}

class DeviceMotionSensor extends SensorBlock<Sensors.DeviceMotionMeasurement> {
  getName = () => 'DangerZone.DeviceMotion';
  getSensor = () => Sensors.DeviceMotion;
  renderXYZBlock = (name: string, { x, y, z }: { x?: number; y?: number; z?: number } = {}) => (
    <Text>
      {name}: x: {round(x)} y: {round(y)} z: {round(z)}
    </Text>
  );
  renderABGBlock = (
    name: string,
    { alpha, beta, gamma }: { alpha?: number; beta?: number; gamma?: number } = {}
  ) => (
    <Text>
      {name}: α: {round(alpha)} β: {round(beta)} γ: {round(gamma)}
    </Text>
  );
  renderData = () => (
    <View>
      {this.renderXYZBlock('Acceleration', this.state.data.acceleration)}
      {this.renderXYZBlock('Acceleration w/gravity', this.state.data.accelerationIncludingGravity)}
      {this.renderABGBlock('Rotation', this.state.data.rotation)}
      {this.renderABGBlock('Rotation rate', this.state.data.rotationRate)}
      <Text>Orientation: {this.state.data.orientation}</Text>
    </View>
  );
}

class BarometerSensor extends SensorBlock<Sensors.BarometerMeasurement> {
  getName = () => 'Barometer';
  getSensor = () => Sensors.Barometer;
  renderData = () => (
    <View>
      <Text>Pressure: {this.state.data.pressure}</Text>
      <Text>Relative Altitude: {this.state.data.relativeAltitude}</Text>
    </View>
  );
}

function round(n?: number) {
  if (!n) {
    return 0;
  }

  return Math.floor(n * 100) / 100;
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    marginBottom: 10,
  },
  buttonContainer: {
    flexDirection: 'row',
    alignItems: 'stretch',
    marginTop: 15,
  },
  button: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#eee',
    padding: 10,
  },
  middleButton: {
    borderLeftWidth: 1,
    borderRightWidth: 1,
    borderColor: '#ccc',
  },
  sensor: {
    marginTop: 15,
    paddingHorizontal: 10,
  },
});