addressFinal.js

const styles = StyleSheet.create({
    container: {
        flex: 1,
        display: "flex",
        flexDirection: "column",
        justifyContent: "center",
        alignItems: "center",
        maxHeight: 400
    },
    inputStyle : {
        minHeight: 80,
        width: width,
        backgroundColor: "white",
        margin: 1,
        padding: 20,
        alignSelf: "center",
        borderColor: "white",
        borderWidth: 1
    }
});

render() {
  return (
    <View style={styles.container}>
        <TextInput
          style={styles.inputStyle}
          ref={addressEntry => (this._addressEntry = addressEntry)}
          placeholder="Address"
          maxLength={60}
          onChangeText={streetName => 
                        this.validateAndSetAttribute("streetName", streetName)}
        />

        <TextInput
          style={styles.inputStyle}
          ref={cityEntry => (this._cityEntry = cityEntry)}
          placeholder="City"
          maxLength={58}
          onChangeText={city => this.validateAndSetAttribute("city", city)}
        />

        <TextInput
          style={styles.inputStyle}
          ref={postcodeEntry => (this._postcodeEntry = postcodeEntry)}
          placeholder="Postcode"
          maxLength={8}
          onChangeText={postcode => 
                        this.validateAndSetAttribute("postcode", postcode)}
        />
    </View>
  )
}