Error with image upload in react native with react native fetch blob

I have an app to connect user and I have a problem to upload images and put download url in database.
I'm using:

• Node: 12.9.1
  
• Yarn: 1.13.0
  
• npm: 6.10.2
  
• react-native-cli: 2.0.1
  
• react-native: 0.60.5
  

I will put my code here:

import React, {useState} from 'react';
import {
    View,
    ImageBackground,
    Image,
    Text,
    TextInput,
    TouchableOpacity,
    StyleSheet,
    ScrollView,
    AsyncStorage,
    Platform,
} from 'react-native';
import {Avatar} from 'react-native-elements';
import ImagePicker from 'react-native-image-picker';
import RNFetchBlob from 'react-native-fetch-blob';

import firebaseApp from '../config/firebaseConfig';

import background from '../assets/background.png';
import logo from '../assets/logo.png';

const Blob = RNFetchBlob.polyfill.Blob;
const fs = RNFetchBlob.fs;
window.XMLHttpRequest = RNFetchBlob.polyfill.XMLHttpRequest;
window.Blob = Blob;

export default class Logon extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            userID: null,
            email: '',
            password: '',
            name: '',
            surname: '',
            birthdate: null,
            picture: null,
            title: '',
            nickname: '',
            errorMessage: null,
            city: '',
        };
    }

    render() {
        return (
            <ImageBackground style={styles.background} source={background}>
                <View style={styles.container}>
                    <Image style={styles.logo} source={logo} />

                    <View style={styles.formContainer}>
                        <ScrollView>
                            <View style={styles.iconContainer}>
                                <Avatar
                                    size="xlarge"
                                    rounded
                                    title="GS"
                                    source={{uri: this.state.picture}}
                                    activeOpacity={0.7}
                                    onPress={() => this.handlePicture()}
                                />
                            </View>
                            <View style={styles.inputContainer}>
                                <Text style={styles.inputText}>Email: </Text>
                                <TextInput
                                    keyboardType="email-address"
                                    autoCapitalize="none"
                                    autoCorrect={false}
                                    placeholder="email@email.com"
                                    placeholderTextColor="#999"
                                    onChangeText={email => this.setState({email})}
                                    style={styles.input}
                                />
                            </View>
                            <View style={styles.inputContainer}>
                                <Text style={styles.inputText}>Senha: </Text>
                                <TextInput
                                    secureTextEntry={true}
                                    autoCapitalize="none"
                                    autoCorrect={false}
                                    onChangeText={password => this.setState({password})}
                                    style={styles.input}
                                />
                            </View>
                            <View style={styles.inputContainer}>
                                <Text style={styles.inputText}>Nome: </Text>
                                <TextInput
                                    style={styles.input}
                                    onChangeText={name => this.setState({name})}
                                />
                            </View>
                            <View style={styles.inputContainer}>
                                <Text style={styles.inputText}>Sobrenome: </Text>
                                <TextInput
                                    style={styles.input}
                                    onChangeText={surname => this.setState({surname})}
                                />
                            </View>
                            <View style={styles.inputContainer}>
                                <Text style={styles.inputText}>Nickname: </Text>
                                <TextInput
                                    style={styles.input}
                                    onChangeText={nickname => this.setState({nickname})}
                                />
                            </View>
                            <View style={styles.buttonContainer}>
                                <TouchableOpacity
                                    style={styles.sendButton}
                                    onPress={() => this.handleLogon()}>
                                    <Text style={styles.sendButtonText}>Enviar</Text>
                                </TouchableOpacity>
                            </View>
                            {/* {this.renderErrorMessage()} */}
                            <View style={styles.logonContainer}>
                                <Text style={styles.logonText}>Já tens a tua conta?</Text>
                                <TouchableOpacity onPress={() => this.handleLogin()}>
                                    <Text style={styles.logoButtonText}>Clica aqui</Text>
                                </TouchableOpacity>
                            </View>
                        </ScrollView>
                    </View>
                </View>
            </ImageBackground>
        );
    }

    handleLogin = () => {
        this.props.navigation.navigate('Login');
    };

    handlePicture = () => {
        ImagePicker.showImagePicker(options, response => {
            if (response.didCancel) {
                return;
            } else if (response.customButton) {
                console.log('User tapped custom button: ', response.customButton);
            } else {
                this.setState({
                    picture: response.uri,
                });
            }
        });
    };

    handleLogon = async () => {
        await firebaseApp
            .auth()
            .createUserWithEmailAndPassword(this.state.email, this.state.password)
            .then(userData => {
                uploadImage(userData.user.uid);
            });
    };
}

export const uploadImage = (userId, mime = 'application/octet-stream') => {
    return dispatch => {
        return new Promise((resolv, reject) => {
            const uri = () => {
                this.state.picture;
            };
            const uploadUri =
                Platform.OS === 'ios' ? uri.replace('file://', '') : uri;
            let uploadBlob = null;
            const imageRef = firebaseApp
                .storage()
                .ref('users')
                .child(userId);
            fs.readFile(uploadUri, 'base64')
                .then(data => {
                    return Blob.build(data, {type: `${mime};BASE64`});
                })
                .then(blob => {
                    uploadBlob = blob;
                    return imageRef.put(blob._ref, blob, {contentType: mime});
                })
                .then(() => {
                    uploadBlob.close();
                    return imageRef.getDownloadURL();
                })
                .then(url => {
                    resolv(url);
                    console.log(url);
                    storeReference(url, userId);
                })
                .catch(error => {
                    reject(error);
                });
        });
    };
};

const storeReference = (downloadUrl, sessionId) => {
    const data = {
        ID: sessionId,
        email: this.state.email,
        name: this.state.name,
        surname: this.state.surname,
        nickname: this.state.nickname,
        picture: downloadUrl,
    };
    firebaseApp
        .database()
        .ref('users/' + sessionId)
        .set(data);
};

const options = {
    title: 'Select Avatar',
    takePhotoButtonTitle: 'Capturar foto',
    chooseFromLibraryButtonTitle: 'Escolher da galeria',
    storageOptions: {
        skipBackup: true,
        path: 'GameSolv',
    },
};

const styles = StyleSheet.create({
    background: {
        width: '100%',
        height: '100%',
    },
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
    },
    logo: {
        width: 500,
        height: 150,
        top: 20,
    },
    formContainer: {
        flex: 1,
        width: '80%',
        paddingTop: 70,
    },
    iconContainer: {
        alignItems: 'center',
        paddingBottom: 20,
    },
    inputContainer: {
        paddingBottom: 20,
    },
    inputText: {
        color: '#FFF',
        fontSize: 16,
        letterSpacing: 3,
    },
    email: {
        height: 46,
        alignSelf: 'stretch',
        backgroundColor: '#FFF',
        borderWidth: 1,
        borderColor: '#ddd',
        borderRadius: 4,
        marginTop: 0,
        paddingHorizontal: 15,
    },
    input: {
        height: 46,
        alignSelf: 'stretch',
        backgroundColor: '#FFF',
        borderWidth: 1,
        borderColor: '#ddd',
        borderRadius: 4,
        marginTop: 0,
        paddingHorizontal: 15,
    },
    sendButton: {
        marginTop: 20,
        marginBottom: 30,
        width: 200,
        height: 45,
        backgroundColor: '#FFF',
        borderRadius: 5,
        justifyContent: 'center',
        alignItems: 'center',
    },
    buttonContainer: {
        alignItems: 'center',
    },
    sendButtonText: {
        fontSize: 30,
        fontWeight: 'bold',
        color: '#622980',
        letterSpacing: 7,
        fontFamily: 'Roboto-Light',
    },
    logonContainer: {
        alignItems: 'center',
        paddingBottom: 20,
    },
    logonText: {
        color: '#FFF',
        fontSize: 16,
        letterSpacing: 3,
    },
    logoButtonText: {
        color: '#fcef21',
        fontSize: 16,
        letterSpacing: 3,
        textDecorationLine: 'underline',
    },
});

Image with the error
It says:

Attempt to invoke interface method 'java.lang.String com.facebook.react.bridge.ReadableMap.getString(java.lang.String)' on a null object reference