Event Handler

import React, { Component } from "react";
import { Button, StyleSheet, TextInput, View } from "react-native";

export default class App extends Component {
    state = {
        email: "",
        password: ""
    };

    constructor(props) {
        super(props);
        this.handleChangeEmail = this.handleChangeEmail.bind(this)
        this.handleChangePassword = this.handleChangePassword.bind(this);
        this.handleLoginPress = this.handleLoginPress.bind(this);
    }

    handleChangeEmail(text) {
        this.setState({
            email: text
        });
    }

    handleChangePassword(text) {
        this.setState({
            password: text
        });
    }

    handleLoginPress() {
        alert(
            `Your email: ${this.state.email}. And your password: ${
                this.state.password
            }`
        );
    }

    render() {
        return (
            <View style={styles.container}>
                <TextInput
                    onChangeText={this.handleChangeEmail}
                    placeholder={"user@email.com"}
                    style={styles.textInput}
                />
                <TextInput
                    onChangeText={this.handleChangePassword}
                    secureTextEntry={true}
                    placeholder={"Your super secret password"}
                    style={styles.textInput}
                />
                <Button title={"Login"} onPress={this.handleLoginPress} />
            </View>
        );
    }
}

const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor: "#F5FCFF",
        justifyContent: "center",
        alignItems: "center"
    },
    welcome: {
        fontSize: 20,
        textAlign: "center",
        margin: 10
    },
    textInput: {
        borderWidth: 1,
        borderColor: "mediumaquamarine",
        height: 45,
        width: 300,
        padding: 5,
        marginBottom: 22
    }
});