For Simon

SimonApp.js

import React from "react";
import { StyleSheet, View, Button, TextInput } from "react-native";
import { Formik, Field } from "formik";
const MyTextInput = ({ field, ...props }) => {
  console.log(field, props);
  return (
    <TextInput
      value={field.value}
      onChangeText={props.form.handleChange(field.name)}
      onBlur={props.form.handleBlur(field.name)}
      style={{ height: 40, borderColor: "gray", borderWidth: 1 }}
    />
  );
};
const MyForm = () => (
  <Formik
    initialValues={{ email: "" }}
    onSubmit={(values, { setSubmitting }) => {
      console.log(values);
      alert(values);
      setSubmitting(false);
    }}
    render={({ isSubmitting, handleSubmit }) => {
      return (
        <View>
          <Field name="email" component={MyTextInput} />
          <Button
            onPress={handleSubmit}
            title="Submit"
            disabled={isSubmitting}
          />
        </View>
      );
    }}
  />
);

export default class App extends React.Component {
  render() {
    return (
      <View style={styles.container}>
        <MyForm />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: "#fff",
    alignItems: "center",
    justifyContent: "center"
  }
});