AddACard2.js

import React, { Component } from 'react';
import { View, Text } from 'react-native';
import { Card, CardItem, Button, Item, Label, Input } from 'native-base';
class AddACard extends Component {
    constructor(props) {
        super(props);
        this.state = {
            cardValue: '',//<--- Nuevo
            cards: [] //<--- Nuevo
        }
    }
  
    //nuevo
    handleInputText(value) {
        this.setState({
            cardValue: value
        })
    }
    //nuevo
  
    render() {
        return (
            
            <View style={{ padding: 10 }}>
                <Card>
                    <CardItem header>
                        <Text>
                            Añade una tarjeta
                    </Text>
                    </CardItem>
                    <CardItem>
                        <Item floatingLabel>
                            <Label>Front</Label>
                            <Input
                            // nuevo
                                value={this.state.cardValue}
                                onChangeText={
                                    (text)=>{
                                        this.handleInputText(text)
                                    }
                                }
                            //nuevo
                            />
                        </Item>
                    </CardItem>
                    <CardItem footer>
                        <Button block light>
                            <Text>
                                Añadir
                        </Text>
                        </Button>
                    </CardItem>
                </Card>

            </View>
            
        );
    }
}

export default AddACard;