class Item extend React.Component {
  state = {
    checked: false,
  }

  render() {
    return() {
      <Block padding={[10, 15, 20, 15]} color='#EFF8FF' margin={[0, 0, 1, 0]} row center middle key={index}>
        <Block styles={styles.ContainerAssign} flex={0.3}>
            <Switch
                style={{ transform: [{ scaleX: .8 }, { scaleY: .8 }] }}
                value={this.state.checked} //  i would like to check just one of these
                testID={index}
                onValueChange={(value) => this.containerSelected(value, item, index)}
            />
        </Block>

        <Block styles={styles.ContainerInfo} padding={[0, 5, 0, 0]}>
            <Text style={styles.ContainerInfoText}>
                <Text style={styles.ContainerInfoTitle}> Container ID:              </Text>  {item.CtrId}
            </Text>
            ... // code would be too long to displa
        </Block>

        <Button
            ... // code would be too long to display
        </Button>
    </Block>
    }
  }
}

renderItem = {({item}) => <Item item={item}/>}