vds_quiz/vds-app/App/screens/Setup.js

import React from "react"
import { View, ScrollView, StyleSheet, StatusBar, Text, CheckBox, SafeAreaView, Dimensions, Image, BackHandler, AsyncStorage} from "react-native"

import { Button, ButtonContainer } from "../components/Button"
import { colors, texts, examScheme, resultsScheme} from "../components/Variables"

const screen = Dimensions.get("window")
const header = require("../assets/header.png")

const pkg = require('../../app.json')

const styles = StyleSheet.create({
  container: {
    backgroundColor: colors.dark_blue,
    flex: 1
  },
  safearea: {
    flex: 1,
    marginTop: 25,
    justifyContent: "space-between",
    paddingHorizontal: 10
  },

  box: {
    width: screen.width-20,
    paddingHorizontal: 10
  },
  text: {
    color: colors.white,
    fontSize: 16,
    textAlign: "center",
    fontWeight: "400",
    lineHeight: 20,
    textShadowColor: 'rgba(0, 0, 0, 0.75)',
    textShadowOffset: {width: -1, height: 1},
    textShadowRadius: 5
  },
  title: {
    paddingTop: 30,
    color: colors.white,
    fontSize: 18,
    textTransform: "uppercase",
    textAlign: "center",
    fontWeight: "400",
    lineHeight: 20,
    textShadowColor: 'rgba(0, 0, 0, 0.75)',
    textShadowOffset: {width: -1, height: 1},
    textShadowRadius: 5
  },
  textSmall: {
    lineHeight: 23,
    marginTop: 15,
    borderRadius: 20,
    backgroundColor: colors.white,
    borderWidth: 0,
    borderColor: colors.white_alpha,
    fontSize: 16,
    color: colors.white,
    fontWeight: "400",
    textAlign: "center",
    paddingHorizontal: 20,
    paddingVertical: 20,
    textShadowColor: 'rgba(0, 0, 0, 0.75)',
    textShadowOffset: {width: -1, height: 1},
    textShadowRadius: 5
  },
  textItems: {
    fontSize: 16,
    fontWeight: "400",
    lineHeight: 23,
    color: colors.white,
    textAlign: "center",
    paddingBottom: 10,
    marginBottom: 10,
    borderBottomColor: colors.white_alpha,
    borderBottomWidth: 1,
    textShadowColor: 'rgba(0, 0, 0, 0.55)',
    textShadowOffset: {width: -1, height: 1},
    textShadowRadius: 2
  },
  noBorder: {
    borderBottomWidth: 0
  },
  item: {
    width: "100%"
  },
  noPadding: {
    paddingVertical: 0,
  },
  textLabel: {
    paddingHorizontal: 20,
    paddingVertical: 20
  },
  bold: {
    lineHeight: 30,
    fontSize: 26,
    fontWeight: "600"
  },

  checkboxContainer: {
    flexDirection: "row",
    paddingBottom: 10,
    marginBottom: 10,
    borderBottomColor: colors.black_alpha,
    borderBottomWidth: 1,
  },
  checkbox: {
    alignSelf: "center",
    color: "white"
  },
  checkboxLabel: {
    marginLeft: 8,
    marginRight: 8
  }
})

const B = (props) => <Text style={{fontWeight: 'bold'}}>{props.children}</Text>

class Setup extends React.Component {

  state = {
    setupData: {}
  }

  componentDidMount() {
    BackHandler.addEventListener('hardwareBackPress', this.handleBackButton)
    AsyncStorage.getItem('setupData').then((value) => {
      let setupData = {}

      if(!value) {
        setupData = {
          randomQuestions: true,
          excludeDelta: false
        }
        AsyncStorage.setItem('setupData', JSON.stringify(setupData))
      } else {
        setupData = JSON.parse(value)
      }

      this.setState( (state) => {
        return {
          setupData: setupData
        }
      })
    }).done()
  }


  componentWillUnmount() {
    BackHandler.removeEventListener('hardwareBackPress', this.handleBackButton)
  }

  handleBackButton = () => {
    this.props.navigation.navigate("Splash")
    return true
  }

  changeSetup = (item) => {
    setupData = this.state.setupData
    setupData[item] = !this.state.setupData[item]

    this.setState( (state) => {
      return {
        setupData: setupData
      }
    })

    AsyncStorage.setItem('setupData', JSON.stringify(setupData))
  }

  render() {

    return (
      <View style={styles.container} >

        <SafeAreaView style={styles.safearea}>
          <ScrollView>
            <View style={styles.box}>

              <Text style={styles.title}>
                {texts.setupScheme}
              </Text>

              <View style={styles.textSmall}>

                <View style={styles.checkboxContainer}>
                  <CheckBox
                    value={this.state.setupData.randomQuestions}
                    onValueChange={() => this.changeSetup('randomQuestions')}
                    style={styles.checkbox}
                  />
                  <Text style={styles.checkboxLabel}>{texts.setupRandomCheck}</Text>
                </View>

                <View style={styles.checkboxContainer}>
                  <CheckBox
                    value={this.state.setupData.excludeDelta}
                    onValueChange={() => this.changeSetup('excludeDelta')}
                    style={styles.checkbox}
                  />
                  <Text style={styles.checkboxLabel}>{texts.setupExcludeDelta}</Text>
                </View>


              </View>

            </View>
          </ScrollView>

        </SafeAreaView>

      </View>
    )
  }
}

export default Setup